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Bai Y, Jiang X, He B, Zhu Y, Zhang Y. Polydimethylsiloxane enabled triple-action water-resistant coating with desirable relaxation rate in clear aligner. J Colloid Interface Sci 2024; 676:701-714. [PMID: 39059277 DOI: 10.1016/j.jcis.2024.07.181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 07/12/2024] [Accepted: 07/21/2024] [Indexed: 07/28/2024]
Abstract
Clear aligners undergo rapid stress relaxation in warm, moist oral environments, compromising therapeutic effectiveness and longevity of treatment. To develop an innovative multilayer composite material with improved stability and reduced stress release, we have engineered an innovative coating characterized by the surface aggregation of polydimethylsiloxane (PDMS), which imparts a pronounced hydrophobic effect. In addition, the chemically and physically cross-linked structure of the coating reduces the free volume created by molecular chain rearrangement owing to the presence of water molecules, thereby minimizing water penetration into the coating. Concurrently, the coating's internal structure is enriched with numerous polar functional groups to capture water molecules that penetrate into the inside of the coating. Through combination of these mechanisms, water molecules are effectively sequestered, thereby impeding their penetration into the polyethylene terephthalate glycol (PETG) substrate. The impact of the polydimethylsiloxane content on the triple-action water-resistance mechanisms was thoroughly examined using attenuated total reflection (ATR)-Fourier transform infrared (FTIR), water absorption rate, water swelling rate, and X-ray photoelectron spectroscopy. The low surface energy cross-linked polyurethane coating is applied to the polyethylene terephthalate glycol (PETG) substrate to create a novel composite material with specific mechanical properties and reduced stress relaxation. The composite material remains stable in simulated oral environment with linear swelling rate of 0.58 % upon water absorption. Additionally, the stress release rate of the composite material within 336 h is notably lower (23.64 %) than that of PETG (62.29 %).
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Affiliation(s)
- Yun Bai
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 611731, Sichuan, China
| | - Xiaoli Jiang
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 611731, Sichuan, China
| | - Bin He
- National Engineering Research Center for Biomaterials, School of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
| | - Yabin Zhu
- Biomedical Engineering Research Center, Medical School of Ningbo University, Ningbo 315211, Zhejiang, China
| | - Yagang Zhang
- School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 611731, Sichuan, China.
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Qiang R, Gao J, Wang Y, Wang W, Ma Y, Jin Z. Anchorage loss of the posterior teeth under different extraction patterns in maxillary and mandibular arches using clear aligner: a finite element study. BMC Oral Health 2024; 24:1204. [PMID: 39390419 PMCID: PMC11465488 DOI: 10.1186/s12903-024-04951-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Accepted: 09/24/2024] [Indexed: 10/12/2024] Open
Abstract
BACKGROUND Extracting the premolars is an effective strategy for patients with bimaxillary dentoalveolar protrusion. Clear aligners (CAs) close the extraction spaces through shortening the length of aligners. The contraction force generated by the terminal of aligners makes the posterior teeth tip mesially, which is known as the roller coaster effect. This phenomenon is even worse in the 2nd premolar extraction cases. Posterior anchorage preparation is commonly used to protect the angulation of molars, taking the form of presetting distal tipping value. However, the distal tipping design aggravates the anchorage loss of anterior teeth simultaneously. This study aimed to explore the different anchorage loss of the posterior teeth when the 1st or 2nd premolars were extracted using CAs, respectively in maxillary and mandibular arches, further providing guidance for anchorage preparation design in clinical practice. METHODS Two bimaxillary finite element models with different extraction patterns were established to simulate the anterior en-masse retraction process of the CAs. In Model 1, the maxillary and mandibular 1st premolars were extracted, while in Model 2, the 2nd premolars were extracted. Finite element analysis methods were utilized to analyze the tipping angle of the anterior and posterior teeth. RESULTS Compared between two models, the anterior teeth exhibited a greater lingual inclination tendency and the posterior teeth exhibited a slighter mesial tipping tendency in Model 1 regarding individual tooth. The closer to the extraction spaces, the greater the tip, and the distal tipping tendency of the 1st premolars was more evident than the mesial tipping tendency of the 1st molars in Model 2. Compared between the maxillary and mandibular arches, the mesial tipping tendency of individual posterior tooth was more evident in the maxilla. In addition, the highest hydrostatic stress of the periodontal ligaments was concentrated on the cervical and apical parts directly adjacent to the extraction spaces, and it exhibited relatively uniform distribution in Model 1. CONCLUSIONS The individual posterior tooth showed the same mesial tipping direction but to different degree when the 1st or the 2nd premolars were extracted during clear aligner treatment. Presetting anchorage preparation design for the posterior teeth is essential to alleviate the roller coaster effect, especially in the 2nd premolar extraction cases. Furthermore, larger anchorage preparation value should be proposed for the maxillary posterior teeth.
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Affiliation(s)
- Ruyue Qiang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi' an, 710032, China
| | - Jie Gao
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi' an, 710032, China
| | - Yanqi Wang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi' an, 710032, China
| | - Wei Wang
- Urumql DW Innovation InfoTech Co.Ltd, Xinjiang, 830000, China
| | - Yanning Ma
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi' an, 710032, China.
- Department of Orthodontics, Shanxi Medical University School and Hospital of Stomatology, Taiyuan, 030001, China.
| | - Zuolin Jin
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, Air Force Medical University, Xi' an, 710032, China.
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Bruni A, Ferrillo M, Gallo V, Parrini S, Garino F, Castroflorio T, Deregibus A. Efficacy of clear aligners vs rapid palatal expanders on palatal volume and surface area in mixed dentition patients: A randomized controlled trial. Am J Orthod Dentofacial Orthop 2024; 166:203-214. [PMID: 39066746 DOI: 10.1016/j.ajodo.2024.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 04/01/2024] [Accepted: 04/01/2024] [Indexed: 07/30/2024]
Abstract
INTRODUCTION This study aimed to evaluate the efficacy of Invisalign First Phase I treatment compared with tooth-borne rapid maxillary expansion (RME) in mixed dentition patients by examining changes in palatal volume, palatal surface area, and maxillary interdental transverse measurements. METHODS In this open-label, 2-arm, parallel, randomized controlled trial, patients with a posterior transverse discrepancy ≤6 mm were allocated into the clear aligner therapy (CAT) group (Invisalign First Phase I treatment) and RME group (tooth-borne RME) according to a computer-generated randomization list immediately before the start of treatment. Digital models were obtained before the beginning of the treatment (T0) and at the end of the retention period/treatment (T1) using an intraoral scanner. Palatal volume was measured as the primary outcome, and palatal surface area and intermolar and intercanine transverse widths at the cusps and gingival level were measured as secondary outcomes. Patients and interventionists were not blinded because of the nature of the intervention. RESULTS Out of 50 patients, 41 (19 males and 22 females; mean age, 8.12 ± 1.53 years) were enrolled and divided into 2 groups: 20 in the CAT group and 21 in the RME group. Two participants did not receive the allocated intervention for different reasons (1 patient discontinued the intervention in the CAT group, and another patient was lost to follow-up in the RME group). Thus, 19 patients (5 males and 14 females; mean age, 8.48 ± 1.42 years) were analyzed from the CAT group, and 20 patients (12 males and 8 females; mean age, 7.83 ± 1.19 years) from the RME group. Regarding intragroup comparisons, all outcome measures significantly increased from T0 to T1 in both groups. In terms of intergroup comparisons, there were no significant differences in the variation (Δ) of outcome measures between the 2 groups from T0 to T1, except for the intermolar width at the gingival level (P <0.005). The change in palatal volume was 532.01 ±540.52 mm³ for the RME group and 243.95 ± 473.24 mm³ for the CAT group (P = 0.084), with a moderate effect size (d = 0.57). CONCLUSIONS RME showed trends favoring better outcomes compared with Invisalign First Phase I treatment across all assessed measures. The only parameter that showed statistically significant differences between the 2 groups was variation in intermolar width at the gingival level, suggesting the occurrence of buccal tipping in patients undergoing Invisalign First Phase I treatment. TRIAL REGISTRATION The trial was registered at ClinicalTrial.gov (no. NCT04760535).
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Affiliation(s)
- Alessandro Bruni
- Department of Surgical Sciences, CIR Dental School, Università degli Studi di Torino, Turin, Italy; Surgical, Medical and Dental Department, University of Modena and Reggio Emilia, Modena, Italy.
| | - Martina Ferrillo
- Dentistry Unit, Department of Health Sciences, Università degli Studi di Catanzaro "Magna Graecia", Catanzaro, Italy
| | - Vittorio Gallo
- Department of Surgical Sciences, CIR Dental School, Università degli Studi di Torino, Turin, Italy
| | - Simone Parrini
- Department of Surgical Sciences, CIR Dental School, Università degli Studi di Torino, Turin, Italy
| | | | | | - Andrea Deregibus
- Department of Surgical Sciences, CIR Dental School, Università degli Studi di Torino, Turin, Italy
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Olteanu ND, Taraboanta I, Panaite T, Balcos C, Rosu SN, Vieriu RM, Dinu S, Zetu IN. Color Stability of Various Orthodontic Clear Aligner Systems after Submersion in Different Staining Beverages. MATERIALS (BASEL, SWITZERLAND) 2024; 17:4009. [PMID: 39203186 PMCID: PMC11355976 DOI: 10.3390/ma17164009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2024] [Revised: 08/08/2024] [Accepted: 08/09/2024] [Indexed: 09/03/2024]
Abstract
This study aimed to compare the color changes in two different orthodontic clear aligner systems after submersion in various beverages for 14 days. The tested aligner systems were Taglus Premium made of polyethylene terephthalate glycol (the TAG group) and CA® Prodin+ made of a transparent copolyester and a thermoplastic elastomer (the PRO group). A total of 56 samples were firstly divided into two groups according to the tested system-TAG and PRO. Each group was subsequently divided in four subgroups according to immersion solution: A-artificial saliva, B-cola, C-coffee, D-red wine. Color measurements were performed on Days 1, 7 and 14 using a portable colorimeter and the CIE L*a*b* system. The obtained results showed significant color changes in both materials when exposed to coffee and red wine (p > 0.05). Samples in the PRO group showed a greater susceptibility to discoloration (higher ΔE values) when compared to the TAG group after submersion in cola (p = 0.025), coffee (p = 0.005) and red wine (p = 0.041) solutions. Statistical analysis revealed that all of the color parameters ΔL*, Δa*, Δb* and ΔE of both tested materials were affected by submersion in coffee solution for 14 days. In conclusion, the CA® Pro+ aligner system is more prone to staining compared to the Taglus material after submersion for 14 days in cola, coffee and red wine solutions. Submersion for 14 days in coffee solution alters all of the color parameters (ΔL, Δa, Δb and ΔE) of both tested aligner materials.
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Affiliation(s)
- Nicolae Daniel Olteanu
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine “Grigore T. Popa”, University of Medicine and Pharmacy from Iasi, Str. Universitatii 16, 700115 Iasi, Romania; (N.D.O.); (I.T.); (T.P.); (C.B.); (R.M.V.); (I.N.Z.)
| | - Ionut Taraboanta
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine “Grigore T. Popa”, University of Medicine and Pharmacy from Iasi, Str. Universitatii 16, 700115 Iasi, Romania; (N.D.O.); (I.T.); (T.P.); (C.B.); (R.M.V.); (I.N.Z.)
| | - Tinela Panaite
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine “Grigore T. Popa”, University of Medicine and Pharmacy from Iasi, Str. Universitatii 16, 700115 Iasi, Romania; (N.D.O.); (I.T.); (T.P.); (C.B.); (R.M.V.); (I.N.Z.)
| | - Carina Balcos
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine “Grigore T. Popa”, University of Medicine and Pharmacy from Iasi, Str. Universitatii 16, 700115 Iasi, Romania; (N.D.O.); (I.T.); (T.P.); (C.B.); (R.M.V.); (I.N.Z.)
| | - Sorana Nicoleta Rosu
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine “Grigore T. Popa”, University of Medicine and Pharmacy from Iasi, Str. Universitatii 16, 700115 Iasi, Romania; (N.D.O.); (I.T.); (T.P.); (C.B.); (R.M.V.); (I.N.Z.)
| | - Raluca Maria Vieriu
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine “Grigore T. Popa”, University of Medicine and Pharmacy from Iasi, Str. Universitatii 16, 700115 Iasi, Romania; (N.D.O.); (I.T.); (T.P.); (C.B.); (R.M.V.); (I.N.Z.)
| | - Stefania Dinu
- Department of Pedodontics, Faculty of Dental Medicine, “Victor Babes”, University of Medicine and Pharmacy Timisoara, No. 9, Revolutiei Bv., 300041 Timisoara, Romania;
| | - Irina Nicoleta Zetu
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine “Grigore T. Popa”, University of Medicine and Pharmacy from Iasi, Str. Universitatii 16, 700115 Iasi, Romania; (N.D.O.); (I.T.); (T.P.); (C.B.); (R.M.V.); (I.N.Z.)
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Thilagalavanian A, Weir T, Meade MJ. Analysis of predicted and achieved root angulation changes in teeth adjacent to maxillary premolar extraction sites in patients treated with the Invisalign appliance. Am J Orthod Dentofacial Orthop 2024:S0889-5406(24)00249-X. [PMID: 39066745 DOI: 10.1016/j.ajodo.2024.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 06/01/2024] [Accepted: 06/01/2024] [Indexed: 07/30/2024]
Abstract
INTRODUCTION This study aimed to investigate the expression of root angulation in canine, premolar, and first molar teeth adjacent to first and second premolar extraction sites in the maxilla after treatment with an initial series of Invisalign aligners (Align Technology, Santa Clara, Calif). METHODS Adult patients (aged ≥18 years) with at least 1 first and/or second premolar extraction in the maxilla and satisfying strict selection criteria were evaluated. Digital models representing pretreatment, predicted, and posttreatment were obtained from Align Technology's digital interface, ClinCheck. The Geomagic Control X (version 2017.0.3; 3D systems, Rock Hill, NC) software facility was used to determine and compare the root angulation of adjacent canine, premolar, and first molar teeth at different time points. RESULTS The predicted angulation of teeth was significantly different (P <0.02) than that achieved in most patients. When adjacent teeth roots were planned to tip away from the extraction site, there was an overexpression of the movement. When teeth roots were planned to tip into the extraction site, underexpression occurred, and movement was in the opposite direction in some instances. There was no difference in root angulation outcomes according to the prescribed number of aligners, 1- or 2-week wear protocols, and sex (P >0.05). Attachments were influential in controlling angulation in first-premolar extractions (P = 0.05), but optimized attachments were not any more effective than conventional attachments (P >0.05). CONCLUSIONS The achieved root angulation in teeth adjacent to premolar extraction sites in the maxilla after treatment with an initial series of Invisalign aligners differed significantly from that predicted. Attachments play a minor role in the predictability of root angulation outcomes.
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Affiliation(s)
- Abirami Thilagalavanian
- From the Orthodontic Unit, Adelaide Dental School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Tony Weir
- From the Orthodontic Unit, Adelaide Dental School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Maurice J Meade
- From the Orthodontic Unit, Adelaide Dental School, The University of Adelaide, Adelaide, South Australia, Australia.
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Li N, Wang C, Yang M, Chen D, Tang M, Li D, Qiu S, Chen Q, Feng Y. Effects of different tooth movement patterns and aligner thicknesses on maxillary arch expansion with clear aligners: a three-dimensional finite element study. Front Bioeng Biotechnol 2024; 12:1424319. [PMID: 38983604 PMCID: PMC11231920 DOI: 10.3389/fbioe.2024.1424319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 06/07/2024] [Indexed: 07/11/2024] Open
Abstract
Objectives The objective of this study was to investigate the biomechanical effects of different tooth movement patterns and aligner thicknesses on teeth and periodontal tissues during maxillary arch expansion with clear aligners, to facilitate more precise and efficient clinical orthodontic treatments. Methods Three-dimensional models including teeth, maxilla, periodontal ligament, and aligner were constructed and subjected to finite element analysis. Tooth displacement trends and periodontal ligament stresses were measured for seven tooth displacement patterns (divided into three categories including overall movement of premolars and molars with gradually increasing molar expansion in each step; distributed movement of premolars and molars; and alternating movement between premolars and molars at intervals) and two aligner thicknesses (0.5 mm and 0.75 mm) during maxillary arch expansion with clear aligners. Results When expanding the maxillary arch with clear aligners, the effective expansion of the target teeth mainly showed a tilting movement trend. Increasing the amount of molar expansion increased the buccal displacement of the first molar but decreased the buccal displacement of the premolars. The mean buccal displacement of the target teeth was greater in the posterior teeth interval alternating movement group (0.026 mm) than in the premolar/molar distributed movement group (0.016 mm) and the overall movement group (0.015 mm). Increasing aligner thickness resulted in greater buccal displacement of the crowns and increased stress on the periodontal ligaments. Conclusion Increasing the amount of molar expansion reduces the efficiency of premolar expansion. Alternating movement of premolars and molars at intervals achieves a higher arch expansion efficiency, but attention should be paid to the anchorage of adjacent teeth. Increasing the thickness of the aligner increases the expansion efficiency but may also increase the burden on the periodontal tissues.
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Affiliation(s)
- Na Li
- Silk Crossing Clinic, Affiliated Hospital of North Sichuan Medical College, Nanchong, China
- Department of Stomatology, North Sichuan Medical College, Nanchong, China
| | - ChunJuan Wang
- Chongqing Key Laboratory of Oral Diseases, Chongqing Municipal Key Laboratory of Stomatological Biomedical Engineering, Chongqing, China
| | - Min Yang
- Department of Stomatology, North Sichuan Medical College, Nanchong, China
| | - DingGen Chen
- Silk Crossing Clinic, Affiliated Hospital of North Sichuan Medical College, Nanchong, China
- Department of Stomatology, North Sichuan Medical College, Nanchong, China
| | - MingYuan Tang
- Department of Stomatology, North Sichuan Medical College, Nanchong, China
| | - DaoKun Li
- Department of Stomatology, North Sichuan Medical College, Nanchong, China
| | - ShengLei Qiu
- Department of Stomatology, North Sichuan Medical College, Nanchong, China
| | - Qi Chen
- Department of Stomatology, North Sichuan Medical College, Nanchong, China
| | - Yi Feng
- Department of Stomatology, North Sichuan Medical College, Nanchong, China
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Porojan L, Toma FR, Gherban MI, Vasiliu RD, Matichescu A. Surface Topography of Thermoplastic Appliance Materials Related to Sorption and Solubility in Artificial Saliva. Biomimetics (Basel) 2024; 9:379. [PMID: 39056820 PMCID: PMC11274910 DOI: 10.3390/biomimetics9070379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 06/07/2024] [Accepted: 06/15/2024] [Indexed: 07/28/2024] Open
Abstract
(1) Background: PETG (polyethylene terephthalate glycol) is a transparent, inexpensive, and versatile thermoplastic biomaterial, and it is increasingly being used for a variety of medical applications in dentistry, orthopedics, tissue engineering, and surgery. It is known to have remarkable properties such as tensile strength, high ductility, and resistance to chemical insults and heat, but it can be affected by various environmental conditions. The aim of the present study was to evaluate the topographical characteristics of four thermoplastic dental appliance materials in relation to water sorption in simulated oral environments (artificial saliva samples with different pH values). (2) Methods: The following four types of PETG clear thermoplastic materials were selected for the present study: Leone (L), Crystal (C), Erkodur (E), and Duran (D). In relation to the desiccation and water-uptake stages, their water sorption (Wsp) and solubility (Wsl) were calculated, and the surface topographies were analyzed on two length scales. The surface roughness was determined using a contact profilometer, and nanoroughness measurements were generated by three-dimensional profiles using an atomic force microscope (AFM). Statistical analyses (one-way ANOVA and unpaired and paired Student t-tests) were performed. (3) Results: After saliva immersion, the weights of all samples increased, and the highest sorption was recorded in a basic environment. Among the materials, the water uptake for the L samples was the highest, and for E, it was the lowest. In relation to water solubility, significant values were registered for both the L and C samples' materials. After immersion and desiccation, a decreasing trend in microroughness was observed. The AFM high-resolution images reflected more irregular surfaces related to saliva immersion. (4) Conclusions: The sorption rates recorded in water-based artificial saliva were higher for basic pH levels, with significant differences between the samples. There were also significant differences related to the behaviors of the materials included in the study. In relation to roughness, on a microscale, the surfaces tended to be smoother after the saliva immersions, and on a nanoscale, they became more irregular.
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Affiliation(s)
- Liliana Porojan
- Department of Dental Prostheses Technology (Dental Technology), Center for Advanced Technologies in Dental Prosthodontics, Faculty of Dental Medicine, “Victor Babeș” University of Medicine and Pharmacy Timișoara, Eftimie Murgu Sq. No. 2, 300041 Timisoara, Romania; (F.R.T.); (R.D.V.)
| | - Flavia Roxana Toma
- Department of Dental Prostheses Technology (Dental Technology), Center for Advanced Technologies in Dental Prosthodontics, Faculty of Dental Medicine, “Victor Babeș” University of Medicine and Pharmacy Timișoara, Eftimie Murgu Sq. No. 2, 300041 Timisoara, Romania; (F.R.T.); (R.D.V.)
| | - Mihaela Ionela Gherban
- National Institute for Research and Development in Electrochemistry and Condensed Matter, 300569 Timisoara, Romania;
| | - Roxana Diana Vasiliu
- Department of Dental Prostheses Technology (Dental Technology), Center for Advanced Technologies in Dental Prosthodontics, Faculty of Dental Medicine, “Victor Babeș” University of Medicine and Pharmacy Timișoara, Eftimie Murgu Sq. No. 2, 300041 Timisoara, Romania; (F.R.T.); (R.D.V.)
| | - Anamaria Matichescu
- Department of Preventive, Community Dentistry and Oral Health, Center for Advanced Technologies in Dental Prosthodontics, Faculty of Dental Medicine, “Victor Babes” University of Medicine and Pharmacy Timișoara, Eftimie Murgu Sq. No. 2, 300041 Timisoara, Romania;
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Elshazly TM, Bourauel C, Ismail AM, Ghoraba O, Chavanne P, Elattar H, Alhotan A. Effect of thermomechanical ageing on force transmission by orthodontic aligners made of different thermoformed materials: An experimental study. Orthod Craniofac Res 2024. [PMID: 38887908 DOI: 10.1111/ocr.12825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2024] [Indexed: 06/20/2024]
Abstract
OBJECTIVES Investigating the impact of thermal and mechanical loading on the force generation of orthodontic aligners made from various thermoplastic materials and different compositions. MATERIALS AND METHODS Five distinct materials were utilized including, three multi-layer (Zendura FLX, Zendura VIVA, CA Pro) and two single-layer (Zendura A and Duran). A total of 50 thermoformed aligners (n = 10) underwent a 48-hour ageing protocol, which involved mechanical loading resulting from a 0.2 mm facial malalignment of the upper right central incisor (Tooth 11) and thermal ageing through storage in warm distilled water at 37°C. The force exerted on Tooth 11 of a resin model was measured both before and after ageing using pressure-sensitive films and a biomechanical setup. RESULTS Before ageing, pressure-sensitive films recorded normal contact forces ranging from 83.1 to 149.7 N, while the biomechanical setup measured resultant forces ranging from 0.1 to 0.5 N, with lingual forces exceeding facial forces. Multi-layer materials exhibited lower force magnitudes compared to single-layer materials. After ageing, a significant reduction in force was observed, with some materials experiencing up to a 50% decrease. Notably, multi-layer materials, especially Zendura VIVA, exhibited lower force decay. CONCLUSIONS The force generated by aligners is influenced by both the aligner material and the direction of movement. Multi-layer materials exhibit superior performance compared to single-layer materials, primarily because of their lower initial force, which enhances patient comfort, and their capability to maintain consistent force application even after undergoing ageing.
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Affiliation(s)
- Tarek M Elshazly
- Oral Technology, Dental School, University Hospital Bonn, Bonn, Germany
| | | | - Ahmed M Ismail
- Oral Technology, Dental School, University Hospital Bonn, Bonn, Germany
- Biomaterials Department, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
| | - Omar Ghoraba
- Oral Technology, Dental School, University Hospital Bonn, Bonn, Germany
| | | | - Hanaa Elattar
- Orthodontic Department, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt
| | - Abdulaziz Alhotan
- Department of Dental Health, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
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Medeiros RB, Santos RF, Mendes-Miguel JA, Rothier EKC, Mendes FM, Dominguez GC. Accuracy of arch expansion with two thermoplastic materials in Invisalign® patients: EX30® and SmartTrack®. Dental Press J Orthod 2024; 29:e2423212. [PMID: 38865514 PMCID: PMC11163956 DOI: 10.1590/2177-6709.29.2.e2423212.oar] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 03/25/2024] [Indexed: 06/14/2024] Open
Abstract
OBJECTIVE The purpose of this retrospective study was to compare accuracy of arch expansion using two different thermoplastic materials in Invisalign aligners: EX30® (Polyethylene Terephthalate Glycol, or PETG) and SmartTrack® (polyurethane). METHODS The study sample comprised 65 adult patients consecutively treated with Invisalign from two private practices: group 1 - treated with EX30® (358 teeth) and group 2 - treated with SmartTrack® (888 teeth). Six hundred and twenty-three measurements were assessed in three digital models throughout treatment: model 1 - initial, model 2 - predicted tooth position, and model 3 - achieved position. Sixteen reference points per arch were marked and, after best alignment, 2 points per tooth were copied from one digital model to another. Linear values of both arches were measured for canines, premolars, and first molars: on lingual gingival margins and cusp tips of every tooth. Comparisons were performed by Wilcoxon and Mann-Whitney test. RESULTS Both termoplastic materials presented significant differences between predicted and achieved values for all measurements, except for the lower molar cusp tip in the SmartTrack® group. There is no statistical difference in the accuracy of transverse expansion between these two materials. Overall accuracy for EX30® aligners in maxilla and mandible were found to be 37 and 38%, respectively; and Smarttrack® presented an overall accuracy of 56.62% in the maxilla and 68.72% in the mandible. CONCLUSIONS It is not possible to affirm one material expands better than the other. Further controlled clinical studies should be conducted comparing SmartTrack® and EX30® under similar conditions.
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Affiliation(s)
- Raquel Bueno Medeiros
- Universidade de São Paulo, Faculdade de Odontologia, Departamento de Ortodontia (São Paulo/SP, Brazil)
| | - Renata Faria Santos
- Universidade de São Paulo, Faculdade de Odontologia, Departamento de Ortodontia (São Paulo/SP, Brazil)
| | - Jose Augusto Mendes-Miguel
- Universidade Estadual do Rio de Janeiro, Faculdade de Odontologia, Departamento de Ortodontia (Rio de Janeiro/RJ, Brazil)
| | | | - Fausto Medeiros Mendes
- Universidade de São Paulo, Faculdade de Odontologia, Departamento de Odontopediatria (São Paulo/SP, Brazil)
| | - Gladys Cristina Dominguez
- Universidade de São Paulo, Faculdade de Odontologia, Departamento de Ortodontia (São Paulo/SP, Brazil)
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Bandić R, Vodanović K, Vuković Kekez I, Medvedec Mikić I, Galić I, Kalibović Govorko D. Thickness Variations of Thermoformed and 3D-Printed Clear Aligners. Acta Stomatol Croat 2024; 58:145-155. [PMID: 39036327 PMCID: PMC11256873 DOI: 10.15644/asc58/2/4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/30/2024] [Indexed: 07/23/2024] Open
Abstract
Objective To assess thickness variations of thermoformed and 3D-printed clear aligners. Materials and Methods Six different thermoplastic materials with different initial thicknesses were used for aligner thermoforming using Biostar® device (Biostar®, SCHEU-DENTAL GmbH, Iserlohn, Germany). Also, two different dental resins were used to create the printed aligners in three digitally designed thicknesses using IZZI Direct printer (3Dtech, Zagreb, Croatia). The aligners were measured using an electronic micrometer (ELECTRONIC UNIVERSAL MICROMETER, Schut Geometrical Metrology, Groningen, The Netherlands, accuracy: 0.001 mm) on a total of 20 points per aligner. Statistical analysis was performed using the JASP program (JASP, University of Amsterdam, Amsterdam, The Netherlands). Results The difference between the thermoformed and printed groups was statistically significant. Significant differences between different thermoformed materials and between 3D-printed materials were found. The thickness of thermoformed aligners deviated more in the upper jaw, whereas the thickness of printed aligners deviated more in the lower jaw. Both differences were statistically significant. The greatest average deviation from the initial thickness was found in Duran 0.75; Erkodur 0.6; Erkoloc-Pro 1.0; IZZI 0.5; NextDent 0.6 and NextDent A 0.6. NextDent group had the lowest deviations for all teeth of both jaws, except for upper and lower first molar where NextDent A group was more accurate. Conclusions Thermoformed aligners showed decreased values, while printed ones showed mostly increased values compared to the original material thickness. The highest mean deviation belonged to IZZI group, and the NextDent group had the lowest mean deviation. The thickness of both aligners was thinner at the edges compared to the thickness at cusps and fissures.
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Affiliation(s)
- Ružica Bandić
- Department of Orthodontics, University of Split School of Medicine
| | | | | | - Ivana Medvedec Mikić
- Department of Endodontics and Restorative Dental Medicine, University of Split School of Medicine
- Department of Oral Surgery, University of Split School of Medicine
| | - Ivan Galić
- Department of Oral Surgery, University of Split School of Medicine
- Department of Maxillofacial Surgery, University Hospital of Split
| | - Danijela Kalibović Govorko
- Department of Orthodontics, University of Split School of Medicine
- Department of Maxillofacial Surgery, University Hospital of Split
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11
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D'Antò V, Rongo R, Casaburo SD, Martina S, Petrucci P, Keraj K, Valletta R. Predictability of tooth rotations in patients treated with clear aligners. Sci Rep 2024; 14:11348. [PMID: 38762583 PMCID: PMC11102536 DOI: 10.1038/s41598-024-61594-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Accepted: 05/07/2024] [Indexed: 05/20/2024] Open
Abstract
Clear aligners are employed daily for the treatment of several malocclusions. Previous clinical studies indicated low accuracy for the correction of tooth rotations. The aim of this study was to evaluate the predictability of tooth rotations with clear aligners. The sample comprised 390 teeth (190 mandibular; 200 maxillary), measured from the virtual models of 45 participants (21 men, 24 women; mean age: 29.2 ± 6.6 years old). For each patient, pre-treatment (T0) digital dental models (STL files), virtual plan (T1) and post-treatment digital dental models (T2) of both the mandibular and maxillary arches were imported onto Geomagic Control X, a 3D metrology software which allows angular measurements. Rotations were calculated by defining reproducible vectors for all teeth in each STL file and superimposing both T0 with T1 to determine the prescribed rotation, and T0 with T2 to determine the achieved rotation. Prescribed and achieved rotations were compared to assess movement's accuracy. The Wilcoxon signed-rank test and paired t-test were used to assess differences between the prescribed and achieved movements (P < 0.05). The overall predictability of rotational movement was 78.6% for the mandibular arch and 75.0% for the maxillary arch. Second molar accuracy was the lowest in both arches. Clear aligners were not able to achieve 100% of the planned movements.
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Affiliation(s)
- Vincenzo D'Antò
- Department of Neurosciences, Reproductive Sciences and Oral Sciences, School of Orthodontics, University of Naples Federico II, Via Pansini, 5, 80131, Naples, Italy.
| | - Roberto Rongo
- Department of Neurosciences, Reproductive Sciences and Oral Sciences, School of Orthodontics, University of Naples Federico II, Via Pansini, 5, 80131, Naples, Italy
| | - Sossio Dario Casaburo
- Department of Neurosciences, Reproductive Sciences and Oral Sciences, School of Orthodontics, University of Naples Federico II, Via Pansini, 5, 80131, Naples, Italy
| | - Stefano Martina
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Via Al-Lende, 84081, Baronissi, Italy
| | - Paolo Petrucci
- Department of Neurosciences, Reproductive Sciences and Oral Sciences, School of Orthodontics, University of Naples Federico II, Via Pansini, 5, 80131, Naples, Italy
| | - Kreshnik Keraj
- Department of Prosthodontic, Faculty of Dental Medicine, University of Medicine, Rruga e "Dibrës", AL1005, Tirana, Albania
| | - Rosa Valletta
- Department of Neurosciences, Reproductive Sciences and Oral Sciences, School of Orthodontics, University of Naples Federico II, Via Pansini, 5, 80131, Naples, Italy
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12
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Elshazly TM, Keilig L, Nang D, Golkhani B, Weber A, Elattar H, Talaat S, Bourauel C. Effect of thermomechanical aging on force system of orthodontic aligners made of different thermoformed materials : An in vitro study. J Orofac Orthop 2024:10.1007/s00056-024-00527-0. [PMID: 38653792 DOI: 10.1007/s00056-024-00527-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 02/23/2024] [Indexed: 04/25/2024]
Abstract
PURPOSE The aim was to investigate the effect of aging by thermocycling and mechanical loading on forces and moments generated by orthodontic clear aligners made from different thermoplastic materials. METHODS A total of 25 thermoformed aligners made from 5 different materials, i.e., Essix ACE® and Essix® PLUS™ (Dentsply Sirona, Bensheim, Germany), Invisalign® (Align Technology, San Jose, CA, USA), Duran®+ (Iserlohn, Germany), Zendura™ (Fremont, CA, USA), underwent a 14-day aging protocol involving mechanical loading (a 0.2 mm vestibular malalignment of the upper left second premolar [tooth 25]) and thermocycling in deionized water (temperature range 5-55 °C). The 3D forces/moments exerted on tooth 25 of a resin model were measured at three time points: before aging (day 0), after 2 days and after 14 days of aging. RESULTS Before aging, extrusion-intrusion forces were 0.6-3.0 N, orovestibular forces were 1.7-2.3 N, and moments as mesiodistal rotation were 0.3-42.1 Nmm. In all directions, multilayer Invisalign® exhibited the lowest force/moment magnitudes. After aging, all materials showed a significant force/moment decay within the first 2 days, except Invisalign® for orovestibular and vertical translation. However, following thermomechanical aging, Duran®+ and Zendura™ aligners had equivalent or even higher vestibular forces (direction of mechanical load). CONCLUSION Thermomechanical aging significantly reduced forces and moments during the first 48 h. Multilayer aligner materials exhibit lower initial forces and moments than single-layer ones, and were less influenced by aging. Material hardening was observed after subjecting some of the aligner materials to mechanical loading. Thus, orthodontists should be aware of possible deterioration of orthodontic aligners over time. This work also sheds light on how material selection impacts the mechanical behavior of aligners and may provide valuable guidance regarding optimal timing for the aligner changing protocol.
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Affiliation(s)
- Tarek M Elshazly
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany.
- Oral Technology, University Hospital Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany.
| | - Ludger Keilig
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany
- Department of Dental Prosthetics, Propaedeutics and Materials Science, Dental School, University Hospital Bonn, Bonn, Germany
| | - Diva Nang
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany
| | - Bijan Golkhani
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany
| | - Anna Weber
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany
| | - Hanaa Elattar
- Orthodontic Department, Faculty of Dentistry, Umm Al-Qura University, Makkah, Saudi Arabia
- Orthodontic Department, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt
| | - Sameh Talaat
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany
- Orthodontic Department, Future University in Egypt, Cairo, Egypt
| | - Christoph Bourauel
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany
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13
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Elshazly TM, Bourauel C, Ismail A, Ghoraba O, Aldesoki M, Salvatori D, Elattar H, Alhotan A, Alkabani Y. Effect of material composition and thickness of orthodontic aligners on the transmission and distribution of forces: an in vitro study. Clin Oral Investig 2024; 28:258. [PMID: 38637429 PMCID: PMC11026231 DOI: 10.1007/s00784-024-05662-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/12/2024] [Indexed: 04/20/2024]
Abstract
OBJECTIVES To investigate the effects of material type and thickness on force generation and distribution by aligners. MATERIALS AND METHODS Sixty aligners were divided into six groups (n = 10): one group with a thickness of 0.89 mm using Zendura Viva (Multi-layer), four groups with a thickness of 0.75 mm using Zendura FLX (Multi-layer), CA Pro (Multi-layer), Zendura (Single-layer), and Duran (Single-layer) sheets, and one group with a thickness of 0.50 mm using Duran sheets. Force measurements were conducted using Fuji® pressure-sensitive films. RESULTS The lowest force values, both active and passive, were recorded for the multi-layered sheets: CA Pro (83.1 N, 50.5 N), Zendura FLX (88.9 N, 60.7 N), and Zendura Viva (92.5 N, 68.5 N). Conversely, the highest values were recorded for the single-layered sheets: Duran (131.9 N, 71.8 N) and Zendura (149.7 N, 89.8 N). The highest force was recorded at the middle third of the aligner, followed by the incisal third, and then the cervical third. The net force between the incisal and cervical thirds (FI-FC) showed insignificant difference across different materials. However, when comparing the incisal and middle thirds, the net force (FI-FM) was higher with single-layered materials. Both overall force and net force (FI-FM) were significantly higher with 0.75 mm compared to those with a thickness of 0.50 mm. CONCLUSIONS Multi-layered aligner materials exert lower forces compared to their single-layered counterparts. Additionally, increased thickness in aligners results in enhanced retention and greater force generation. For effective bodily tooth movement, thicker and single-layered rigid materials are preferred. CLINICAL RELEVANCE This research provides valuable insights into the biomechanics of orthodontic aligners, which could have significant clinical implications for orthodontists. Orthodontists might use this information to more effectively tailor aligner treatments, considering the specific tooth movement required for each individual patient. In light of these findings, an exchangeable protocol for aligner treatment is suggested, which however needs to be proven clinically. This protocol proposes alternating between multi-layered and single-layered materials within the same treatment phase. This strategy is suggested to optimize treatment outcomes, particularly when planning for a bodily tooth movement.
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Affiliation(s)
- Tarek M Elshazly
- Oral Technology, Dental School, University Hospital Bonn, Welschnonnenstr. 17, Bonn, 53111, Germany.
| | - Christoph Bourauel
- Oral Technology, Dental School, University Hospital Bonn, Welschnonnenstr. 17, Bonn, 53111, Germany
| | - Ahmed Ismail
- Oral Technology, Dental School, University Hospital Bonn, Welschnonnenstr. 17, Bonn, 53111, Germany
- Biomaterials Department, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
| | - Omar Ghoraba
- Oral Technology, Dental School, University Hospital Bonn, Welschnonnenstr. 17, Bonn, 53111, Germany
| | - Mostafa Aldesoki
- Oral Technology, Dental School, University Hospital Bonn, Welschnonnenstr. 17, Bonn, 53111, Germany
| | | | - Hanaa Elattar
- Orthodontic Department, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt
| | - Abdulaziz Alhotan
- Department of Dental Health, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Yasmine Alkabani
- Oral and Dental Research Institute, National Research Centre, Giza, Egypt
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14
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Nayak AS, H C KK. A comparative study on tensile strength of various thermoplastic polymers sheets following thermoforming on a pre-treatment and post-treatment maxillary model of a patient: an in vitro study. Clin Oral Investig 2024; 28:240. [PMID: 38570397 DOI: 10.1007/s00784-024-05640-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 03/30/2024] [Indexed: 04/05/2024]
Abstract
OBJECTIVES Thermoplastic polymers show alteration in their mechanical properties after thermoforming on a dental model. The purpose of this in-vitro study was to evaluate the tensile strength of different thermoplastic polymer sheets thermoformed on a pre-treatment (moderate crowding) and post-treatment (well-aligned) maxillary model of a patient. MATERIALS AND METHODS Forty maxillary models (Twenty Pre-treatment & twenty Post-treatment of uniform dimension) were made by duplicating them using alginate Hydrogum 5 (Zhermack). Samples were then divided into eight groups of 5 samples each. The thermoplastic sheets Imprelon® (Scheu-Dent), AVAC R® (Jaypee), Placa Crystal® (BioART), EZ-VAC® (3A Medes)-1.0 mm thick were thermoformed on these models respectively. The sample was retrieved using ceramic bur mounted on a straight hand-piece and subjected for testing using TINIUS Olsen 10ST micro universal testing machine and recorded. RESULTS There was no statistically significant difference (P > .05) in tensile strength of thermoformed thermoplastic polymer sheets between pre-treatment and post-treatment maxillary model. Tensile strength of EZ-VAC (3A Medes) showed higher variation between pre-treatment and post-treatment maxillary model though it was found to be statistically insignificant (P > .05). Significant difference (P < .05) was seen between groups when they were compared separately among pre-treatment and post-treatment models. CONCLUSION Placa Crystal (BioART) among the pre-treatment group, EZ - VAC (3A Medes) among the post-treatment group, showed highest tensile strength. CLINICAL RELEVANCE Results of the study highlights the necessity to test materials in conditions which stands in accordance with the clinical scenario to a considerable extent and also emphasizes the need for further study in aligner.
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Affiliation(s)
- Ashwath S Nayak
- Department of Orthodontics and Dentofacial Orthopedics, Bapuji Dental College and Hospital, Davangere, Karnataka, India, 577004.
| | - Kiran Kumar H C
- Department of Orthodontics and Dentofacial Orthopedics, Bapuji Dental College and Hospital, Davangere, Karnataka, India, 577004
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15
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Barile C, Cianci C, Paramsamy Kannan V, Pappalettera G, Pappalettere C, Casavola C, Suriano C, Ciavarella D. Thermoplastic clear dental aligners under cyclic compression loading: A mechanical performance analysis using acoustic emission technique. J Mech Behav Biomed Mater 2024; 152:106451. [PMID: 38310814 DOI: 10.1016/j.jmbbm.2024.106451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/26/2024] [Accepted: 01/30/2024] [Indexed: 02/06/2024]
Abstract
The objective of this work is to analyse the performance of clear aligners made of thermoplastic materials. Within this framework, the damage evolution stages and damage states of the aligners at different cycles of the compressive loading are evaluated using the Acoustic Emission (AE) technique. Three different clear aligner systems were prepared: thermoformed PET-g (polyethylene terephthalate glycol) and PU (polyurethane), and additively manufactured PU. Cyclic compression tests are performed to simulate 22500 swallows. The mechanical results show that the energy absorbed by the thermoformed PET-g aligner remains stable around 4 Nmm throughout the test. Although the PU-based aligners show a higher energy absorption of about 7 Nmm during the initial phase of the cyclic loading, this gradually decreases after 12500 cycles. The time-domain based, and frequency-based parameters of the stress wave acoustic signals generated by the aligners under compression loading are used to identify the damage evolution stages. The machine learning-based AE results reveal the initiation and termination of the different damage states in the aligners and the frequency-based results distinguish the different damage sources. Finally, the microscopy results validated the damage occurrences in the aligners identified by the AE results. The mechanical test results indicate that the thermoformed PET-g has the potential to match the performance and requirements of the dentistry of the popular Invisalign (additively manufactured PU). The AE results have the potential to identify at which cycles the aligners may start losing their functionality.
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Affiliation(s)
- Claudia Barile
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari, Italy
| | - Claudia Cianci
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari, Italy
| | | | - Giovanni Pappalettera
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari, Italy.
| | - Carmine Pappalettere
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari, Italy
| | - Caterina Casavola
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari, Italy
| | - Carmela Suriano
- Dipartimento di Medicina Sperimentale e Clinica, Università di Foggia, Foggia, Italy
| | - Domenico Ciavarella
- Dipartimento di Medicina Sperimentale e Clinica, Università di Foggia, Foggia, Italy
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16
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Srinivasan B, Padmanabhan S, Srinivasan S. Comparative evaluation of physical and mechanical properties of clear aligners - a systematic review. Evid Based Dent 2024; 25:53. [PMID: 38017152 DOI: 10.1038/s41432-023-00937-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/25/2023] [Indexed: 11/30/2023]
Abstract
INTRODUCTION The clinical effectiveness of clear aligners depends on the material properties both physical and mechanical. The purpose of this systematic review is to evaluate the physical and mechanical properties of different clear aligner materials and changes in the same during and after intra-oral use. METHODS Search was done in five electronic databases: Pubmed, Embase, Scopus, Web of Science and Ovid individually by two reviewers. In vivo, Ex vivo and In vitro studies that evaluated the physical and mechanical properties of clear aligner materials were selected. The risk of bias assessment was performed using a modified Cochrane risk of bias tool. RESULTS From the 24 articles selected, 19 evaluated a single physical property and 23 articles evaluated a single mechanical property of clear aligner materials. All domains in the risk of bias assessment showed low risk of bias except for 'blinding of outcome' which was unclear in almost all the selected studies. Properties such as hardness, optical properties, stiffness, and yield strength were found to be different for different clear aligner materials and were found to change with thermoforming, with intra-oral aging, and in simulated intraoral conditions. Due to heterogenicity in the parameters used to assess physical or mechanical properties a meta-analysis could not be done. CONCLUSIONS Properties like hardness, color, stiffness, stress relaxation and creep behavior were different for various clear aligner materials and were found to deteriorate with thermoforming and intra-oral aging. Polyurethane-based materials have a higher level of hardness and stiffness but exhibit increased creep and stress relaxation properties. PROSPERO REGISTRATION NUMBER CRD42021269597.
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Affiliation(s)
- Bhadrinath Srinivasan
- Department of Orthodontics, Sri Ramchandra Institute of Higher Education and Research, PIN- 600116, Chennai, India
| | - Sridevi Padmanabhan
- Department of Orthodontics, Sri Ramchandra Institute of Higher Education and Research, PIN- 600116, Chennai, India.
| | - Sivakumar Srinivasan
- Department of Applied Mechanics, Indian Institute of Technology (Madras), 600036, Chennai, India
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17
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Ardila CM, Arrubla-Escobar DE, Vivares-Builes AM. Efficacy of microchips and 3D sensors for orthodontic force measurement: A systematic review of in vitro studies. Orthod Craniofac Res 2024. [PMID: 38372469 DOI: 10.1111/ocr.12768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/28/2024] [Accepted: 02/03/2024] [Indexed: 02/20/2024]
Abstract
OBJECTIVE To evaluate the efficacy of microchips and 3D microsensors in the measurement of orthodontic forces. METHODS Through September 2023, comprehensive searches were conducted on PubMed/MEDLINE, SCOPUS and SCIELO without restrictions. RESULTS After removing duplicate entries and applying the eligibility criteria, 23 studies were included for analysis. All the studies were conducted in vitro, and slightly more than half of them were centred on evaluating orthodontic forces exerted by aligners. Eight utilized microchips as measurement tools, while the remaining studies made use of 3D microsensors for their assessments. In the context of fixed appliances, key findings included a high level of agreement in 3-dimensional orthodontic force detection between simulation results and actual applied forces. Incorporating critical force-moment combinations during smart bracket calibration reduced measurement errors for most components. Translational tooth movement revealed a moment-to-force ratio, aligning with the bracket's centre of resistance. The primary findings in relation to aligners revealed several significant factors affecting the forces exerted by them. Notably, the foil thickness and staging were found to have a considerable impact on these forces, with optimal force transmission occurring at a layer height of 150 μm. Furthermore, the type of material used in 3D-printing aligners influenced the force levels, with attachments proving effective in generating extrusive forces. Deliberate adjustments in aligner thickness were observed to alter the forces and moments generated. CONCLUSIONS Microchips and 3D sensors provide precise and quantitative measurements of orthodontic forces in in vitro studies, enabling accurate monitoring and control of tooth movement.
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Affiliation(s)
- Carlos M Ardila
- School of Dentistry, University of Antioquia, Medellín, Colombia
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18
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Atta I, Bourauel C, Alkabani Y, Mohamed N, Kimbe H, Alhotan A, Ghoneima A, Elshazly T. Physiochemical and mechanical characterisation of orthodontic 3D printed aligner material made of shape memory polymers (4D aligner material). J Mech Behav Biomed Mater 2024; 150:106337. [PMID: 38154364 DOI: 10.1016/j.jmbbm.2023.106337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 12/14/2023] [Accepted: 12/16/2023] [Indexed: 12/30/2023]
Abstract
OBJECTIVES To conduct a physiochemical and mechanical material analysis on 3D printed shape-memory aligners in comparison to thermoformed aligners. MATERIALS AND METHODS Four materials were examined, including three thermoformed materials: CA Pro (CP), Zendura A (ZA), Zendura FLX (ZF), and one 3D printed material: Tera Harz (TC-85). Rectangular strips measuring 50 × 10 × 0.5 mm were produced from each material. Five tests were conducted, including differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), shape recovery tests, three-points bending (3 PB), and Vickers surface microhardness (VH). RESULTS DSC recorded glass transition temperatures (Tg) at 79.9 °C for CP, 92.2 °C for ZA, 107.1 °C for ZF, and 42.3 °C for TC-85. In DMA analysis at 20-45 °C, a prominent decrease in storage modulus was observed, exclusively for TC-85, as the temperature increased. Notably, within the temperature range of 30-45 °C, TC-85 exhibited substantial shape recovery after 10 min, reaching up to 86.1 %, while thermoformed materials showed minimal recovery (1.5-2.9 %). In 3 PB test (at 30, 37, 45 °C), ZA demonstrated the highest force at 2 mm bending, while TC-85 exhibited the lowest. Regarding VH at room temperature, there was a significant decrease for both ZA and ZF after thermoforming. ZA had the highest hardness, followed by ZF and TC-85, with CP showing the lowest values. CONCLUSIONS TC-85 demonstrates exceptional shape memory at oral temperature, improving adaptation, reducing force decay, and enabling, together with its higher flexibility, extensive tooth movement per step. Additionally, it maintains microhardness similar to thermoformed sheets, ensuring the durability and effectiveness of dental aligners. CLINICAL RELEVANCE The 3D printed aligner material with shape memory characteristics (4D aligner) has revolutionized the orthodontic aligner field. It showed mechanical properties more suitable for orthodontic treatment than thermoforming materials. Additionally, it offers enhanced control over aligner design and thickness, while optimizing the overall workflow. It also minimizes material wastage, and reduces production expenses.
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Affiliation(s)
- Islam Atta
- Oral Technology, Dental School, University Hospital Bonn, Bonn, Germany
| | | | - Yasmine Alkabani
- Restorative and Dental Materials Department, National Research Centre, Giza, Egypt
| | | | - Hoon Kimbe
- Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Abdulaziz Alhotan
- Department of Dental Health, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed Ghoneima
- Department of Orthodontics and Pediatric Dentistry, Hamdan Bin Mohammed College of Dental Medicine (HBMCDM), Mohammed Bin Rashid University of Medicine and Health Sciences (MBRU), Dubai, United Arab Emirates
| | - Tarek Elshazly
- Oral Technology, Dental School, University Hospital Bonn, Bonn, Germany; Department of Orthodontics and Pediatric Dentistry, Hamdan Bin Mohammed College of Dental Medicine (HBMCDM), Mohammed Bin Rashid University of Medicine and Health Sciences (MBRU), Dubai, United Arab Emirates.
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19
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Camenisch L, Polychronis G, Panayi N, Makou O, Papageorgiou SN, Zinelis S, Eliades T. Effect of printing orientation on mechanical properties of 3D-printed orthodontic aligners. J Orofac Orthop 2024:10.1007/s00056-023-00511-0. [PMID: 38277054 DOI: 10.1007/s00056-023-00511-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 12/07/2023] [Indexed: 01/27/2024]
Abstract
PURPOSE The purpose of this study was to assess differences in the fundamental mechanical properties of resin-made three-dimensional (3D) printed orthodontic aligners according to the printing orientation. METHODS Twenty resin 3D-printed dumbbell-shaped specimens and 20 orthodontic aligners were fabricated and postcured in nitrogen. Half of the specimens and aligners were built in horizontal (H), the other half in vertical (V) directions. The dumbbell-shaped specimens were loaded in a tensile testing machine, while parts of the aligners were embedded in acrylic resin, ground, polished, and then underwent instrumented indentation testing (IIT). Mechanical properties that were assessed included the yield strength (YS), breaking strength (BS), plastic strain (ε), Martens hardness (HM), indentation modulus (EIT), elastic index (ηIT), and indentation relaxation (RIT). Data were analyzed statistically with independent t‑tests or Mann-Whitney tests at α = 5%. RESULTS No significant differences were found between specimens or aligners printed either in a horizontal or a vertical direction (P > 0.05 in all instances). Overall, the 3D-printed aligners showed acceptable mechanical propertied in terms of YS (mean 19.2 MPa; standard deviation [SD] 1.7 MPa), BS (mean 19.6 MPa; SD 1.2 MPa), ε (mean 77%; SD 11%), HM (median 89.0 N/mm2; interquartile range [IQR] 84.5-90.0 NN/m2), EIT (median 2670.5 MPa; IQR 2645.0-2726.0 MPa), ηIT (median 27.5%; IQR 25.9-28.1%), and RIT (mean 65.1%; SD 3.5%). CONCLUSION Printing direction seemed to have no effect on the mechanical properties of 3D-printed resin aligners, which are promising for orthodontic use.
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Affiliation(s)
- Lukas Camenisch
- Clinic of Orthodontics and Pediatric Dentistry, Center for Dental Medicine, University of Zurich, Plattenstr. 11, 8032, Zurich, Switzerland
| | - Georgios Polychronis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Nearchos Panayi
- Department of Dentistry, European University Cyprus, Nicosia, Cyprus
| | - Olga Makou
- Department of Dentistry, European University Cyprus, Nicosia, Cyprus
| | - Spyridon N Papageorgiou
- Clinic of Orthodontics and Pediatric Dentistry, Center for Dental Medicine, University of Zurich, Plattenstr. 11, 8032, Zurich, Switzerland.
| | - Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center for Dental Medicine, University of Zurich, Plattenstr. 11, 8032, Zurich, Switzerland
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20
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Güleç-Ergün P, Arman-Özçırpıcı A, Atakan-Kocabalkan A, Tunçer Nİ. Comparison of the accuracy of three interproximal reduction methods used in clear aligner treatment. Clin Oral Investig 2024; 28:95. [PMID: 38221544 PMCID: PMC10788318 DOI: 10.1007/s00784-024-05499-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 01/07/2024] [Indexed: 01/16/2024]
Abstract
OBJECTIVES To comparatively assess 3 interproximal reduction (IPR) methods used in clear aligner treatment with regard to accuracy, and patient perception of discomfort and anxiety. MATERIALS AND METHODS A total of 42 patients, treated with the Invisalign® system, were included in this prospective trial and received one of the following IPR methods: hand-operated abrasive strips (group 1; 14 patients, 150 teeth), motor-driven 3/4 oscillating segmental discs (group 2; 14 patients, 134 teeth), or motor-driven abrasive strips (group 3; 14 patients, 133 teeth). Accuracy was evaluated using the difference between planned and executed IPR. Anxiety and discomfort levels experienced by the patients were evaluated using a questionnaire of 17 questions. RESULTS The accuracy of IPR was high in groups 2 and 3; however, it was low in group 1 with the executed IPR significantly less than the planned amount. On quadrant-level, executed IPR was significantly less in the upper left quadrant in group 1, and significantly more in the upper right quadrant in group 2. The difference between planned IPR and executed IPR was significant for teeth 11, 21, 32, 33, and 43 in group 1, indicating deficiency. The average difference between planned IPR and executed IPR was 0.08 mm for group 1, 0.09 mm for group 2, and 0.1 mm for group 3. Anxiety and discomfort levels did not differ between the methods, but a negative correlation was observed between age and discomfort and anxiety levels. CONCLUSIONS The overall accuracy of the 2 motor-driven IPR methods was found to be better than the hand-operated system. Maxillary central incisors and mandibular canines were more prone to IPR deficiency when hand-operated abrasive strips were utilized. Patients were similarly comfortable with all 3 methods, and discomfort and anxiety levels decreased with age. CLINICAL RELEVANCE Motor-driven methods have proven to be more effective when compared to the hand-operated ones by means of precision, speed, and patient comfort. If the clinician favors a hand-operated method, it may be advised to perform slightly more IPR especially on mandibular canines and maxillary central incisors.
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Affiliation(s)
- Pelinsu Güleç-Ergün
- Department of Orthodontics, Faculty of Dentistry, Başkent University, Yukarıbahçelievler Mah. 82. Sokak No. 26 06490, Bahçelievler, Ankara, Turkey.
| | - Ayça Arman-Özçırpıcı
- Department of Orthodontics, Faculty of Dentistry, Başkent University, Yukarıbahçelievler Mah. 82. Sokak No. 26 06490, Bahçelievler, Ankara, Turkey
| | - Azize Atakan-Kocabalkan
- Department of Orthodontics, Faculty of Dentistry, Başkent University, Yukarıbahçelievler Mah. 82. Sokak No. 26 06490, Bahçelievler, Ankara, Turkey
| | - Nilüfer İrem Tunçer
- Department of Orthodontics, Faculty of Dentistry, Başkent University, Yukarıbahçelievler Mah. 82. Sokak No. 26 06490, Bahçelievler, Ankara, Turkey
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21
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Jin X, Tian X, Lee Zhi Hui V, Zheng Y, Song J, Han X. The effect of enhanced structure in the posterior segment of clear aligners during anterior retraction: a three-dimensional finite element and experimental model analysis. Prog Orthod 2024; 25:3. [PMID: 38221549 PMCID: PMC10788328 DOI: 10.1186/s40510-023-00502-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 11/21/2023] [Indexed: 01/16/2024] Open
Abstract
BACKGROUND Mesial tipping of posterior teeth occurs frequently during space closure with clear aligners (CAs). In this study, we proposed a new modification of CA by localized thickening of the aligner to form the enhanced structure and investigate its biomechanical effect during anterior retraction. METHODS Two methods were employed in this study. First, a finite element (FE) model was constructed, which included alveolar bone, the first premolars extracted maxillary dentition, periodontal ligaments (PDL), attachments and aligners. The second method involved an experimental model-a measuring device using multi-axis transducers and vacuum thermoforming aligners. Two groups were formed: (1) The control group used common CAs and (2) the enhanced structure group used partially thickened CAs. RESULTS FE model revealed that the enhanced structure improved the biomechanics during anterior retraction. Specifically, the second premolar, which had a smaller PDL area, experienced a smaller protraction force and moment, making it less likely to tip mesially. In the same vein, the molars could resist movement due to their larger PDL area even though they were applied larger forces. The resultant force of the posterior tooth was closer to the center of resistance, reducing the tipping moment. The canine was applied a larger retraction force and moment, resulting in sufficient retraction of anterior teeth. The experimental model demonstrated a similar trend in force variation as the FE model. CONCLUSIONS Enhanced structure allowed force distribution more in accordance with optimal principles of biomechanics during the extraction space closure while permitting less mesial tipping and anchorage loss of posterior teeth and better retraction of anterior teeth. Thus, enhanced structure alleviated the roller coaster effect associated with extraction cases and offered a new possibility for anchorage reinforcement in clear aligner therapy.
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Affiliation(s)
- Xiaohan Jin
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, 14# 3Rd Section of Ren Min Nan Road, Chengdu, 610041, Sichuan Province, China
| | - Xue Tian
- Jiangmen Municipal Stomatology Hospital, Yongli Street, Shengli Road, Jiangmen, 529000, Guangdong Province, China
| | - Victoria Lee Zhi Hui
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, 14# 3Rd Section of Ren Min Nan Road, Chengdu, 610041, Sichuan Province, China
| | - Yikan Zheng
- R&D Center, EA Medical Center Device Technologies Co., Ltd, Middle Branch Road, Wuxi, 214174, Jiangsu Province, China
| | - Jinlin Song
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital of Chongqing Medical University, Chongqing Medical University, 426# Songshibei Road, Chongqing, China
| | - Xianglong Han
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, 14# 3Rd Section of Ren Min Nan Road, Chengdu, 610041, Sichuan Province, China.
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22
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Cintora-López P, Arrieta-Blanco P, Martin-Vacas A, Paz-Cortés MM, Gil J, Aragoneses JM. In vitro analysis of the influence of the thermocycling and the applied force on orthodontic clear aligners. Front Bioeng Biotechnol 2023; 11:1321495. [PMID: 38173871 PMCID: PMC10761475 DOI: 10.3389/fbioe.2023.1321495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
The mechanical properties of polyurethane dental aligners have been studied in an oral environment at 37°C and subjected to thermal cycling between 5°C and 55°C for long periods of time at different mechanical stresses. The aim is to determine the efficacy of the orthodontic aligner at different stress levels, the effect of thermal cycling with therapy time on tooth position correction. Sixty aligners with the same design were studied applying tensions of 0, 3 and 30 N and determining the deformation at different times from 1 to 760 h. Half of these aligners were subjected to stresses submerged in artificial saliva at 37°C and the other half were subjected to thermal cycles between 2°C and 55°C in salivary medium. Deformation was determined using a high-resolution stereo magnifier and ImageJ image analysis software. Water adsorption by the polyurethane was determined at the different test times. The results showed that in the unloaded aligners there is no appreciable deformation, but with thermal cycling there is a light shrinkage of the aligner due to the semi-crystallization process (ordering of polymeric chains) of the polyurethane. When applying loads of 3 and 30 N, creep curves with constant deformation transition zones can be seen. The transition zones decrease as the applied mechanical load increases. In addition, the significant effect of thermal cycling on the reduction of the transition zone of the aligners has been demonstrated. The transition zones are optimal for dental correction as constant stresses are exerted for tooth movement. The effect of thermal cycling shortens the constant deformation zone and reduces tooth alignment time. It was observed that the absorption of water in the aligner is constant after 1 h of immersion and does not exceed 0.4% by weight of absorbed water.
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Affiliation(s)
| | | | - Andrea Martin-Vacas
- Faculty of Dentistry, Alfonso X El Sabio University, Villanueva de la Cañada, Spain
| | | | - Javier Gil
- Faculty of Medicine and Health Sciences, Bionegineering Institute of Technology, International University of Catalunya, Barcelona, Spain
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23
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Šimunović L, Jurela A, Sudarević K, Bačić I, Meštrović S. Differential Stability of One-layer and Three-layer Orthodontic Aligner Blends under Thermocycling: Implications for Clinical Durability. Acta Stomatol Croat 2023; 57:286-299. [PMID: 38283309 PMCID: PMC10812913 DOI: 10.15644/asc57/4/1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/01/2023] [Indexed: 01/30/2024] Open
Abstract
Objectives To optimize the therapeutic usefulness of aligners, it is crucial to understand how their mechanical properties alter with time. Materials and methods Specimens from four different brands, including Duran+, CA® Pro, Zendura A, and Zendura FLX, were produced for material testing of thermoplastic orthodontic aligners (TOA) using dimensions measuring 4mm x 10mm. Each brand's 24 samples were split into three groups as follows: G1 being thermoformed, G2 being thermoformed and underwent 500 thermocycles (simulating 7 days), and G3 being thermoformed and underwent 1000 thermocycles (simulating 14 days). Surface roughness, modulus of elasticity in bending, and spectrophotometry were used to assess the effect of aging on TOAs. Results After 1000 thermocycles, Duran+ had the highest modulus of elasticity and differed statistically from all other groups. The intragroup comparison showed that only Duran+'s elastic modulus significantly changed after 1000 thermocycles in comparison with the control group. Surface roughness values (Ra), did not statistically differ among brands or thermocycling group measures. The change in chemical properties was not significant in any brand. Conclusion One-layer PETG (Duran+) failed to demonstrate stability after in vitro aging, thus suggesting that clinicians should be aware of the change in mechanical properties when using one-layer PETG (Duran +) in a 2 weeks regime.
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Affiliation(s)
- Luka Šimunović
- Department of Orthodontics, School of Dental Medicine, University of Zagreb, Gundulićeva 5, 10000 Zagreb, Croatia
| | | | | | - Ivana Bačić
- Forensic Science Centre "Ivan Vučetić", Ministry of the Interior, Ilica 351, 10000 Zagreb, Croatia
| | - Senka Meštrović
- Department of Orthodontics, School of Dental Medicine, University of Zagreb, Gundulićeva 5, 10000 Zagreb, Croatia
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24
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Mu C, Sun B, Gong Z, Wei Y, Chen L, Zhang W, Wu H, Zhao B. The tooth movement efficiency of different orthodontic thermoplastics for clear aligners: study protocol for a randomized controlled clinical trial. Trials 2023; 24:684. [PMID: 37872599 PMCID: PMC10594683 DOI: 10.1186/s13063-023-07736-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 10/16/2023] [Indexed: 10/25/2023] Open
Abstract
INTRODUCTION With regard to the esthetics and comfort of orthodontic treatment, the requirement for removable clear aligners (CAs) is increasing. Unlike conventional fixed orthodontic appliances, CAs were made of thermoplastic film by thermoforming on the personalized dental models. The construction of orthodontic thermoplastic is a critical factor for orthodontic tooth movement (OTM). Polyethylene terephthalate glycol-modified (PETG) and thermoplastic polyurethane (TPU) are the most commonly orthodontic thermoplastics; however, the evidence of the differences between different orthodontic thermoplastic are limited to vitro environment and the evidence in vivo environment is not available. Therefore, this trial aims to provide reliable evidence for orthodontists' personalized treatment plans whether the two most commonly used orthodontic thermoplastics of PETG and TPU have differences in the efficiency of OTM. METHODS AND ANALYSIS This randomized controlled clinical study will recruit 44 orthodontic patients for orthodontic treatment. All the subjects will be randomized into two groups (PETG and TPU, n = 22 for each group). In the first stage (M0 to M1), clear aligners will be made of two orthodontic thermoplastics and move the maxillary first or second premolars 2 mm. In the second stage, patients will take the standard orthodontic treatments. The primary outcome will be the efficiency of clear aligners made of different materials on the digital models. The secondary outcome will be the efficiency of clear aligners made of different materials on the cone-beam computed tomography (CBCT). The efficiency will be calculated through the superimposition of the digital models and CBCT. DISCUSSION The results from this trial will serve as evidence for orthodontists and manufacturers and clarify whether the difference in orthodontic thermoplastics significantly impacts the efficiency of OTM. TRIAL REGISTRATION NUMBER ChiCTR2300070980. Registered on 27 April 2023. https://www.chictr.org.cn/showproj.html?proj=186253.
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Affiliation(s)
- Chuangchuang Mu
- Department of Orthodontics, Shanghai Stomatological Hospital, Fudan University, No.356 Beijing East Road, Shanghai, China
| | - Bingjing Sun
- Department of Orthodontics, Shanghai Stomatological Hospital, Fudan University, No.356 Beijing East Road, Shanghai, China
| | - Zhicheng Gong
- Department of Dental Technology, Shanghai Stomatological Hospital, Fudan University, Shanghai, China
| | - Yuanyuan Wei
- Department of Orthodontics, Shanghai Stomatological Hospital, Fudan University, No.356 Beijing East Road, Shanghai, China
| | - Li Chen
- Department of Orthodontics, Shanghai Stomatological Hospital, Fudan University, No.356 Beijing East Road, Shanghai, China
| | - Wei Zhang
- Department of Orthodontics, Shanghai Stomatological Hospital, Fudan University, No.356 Beijing East Road, Shanghai, China
- Department of Biostatistics, School of Public Health, Fudan University, Shanghai, China
| | - Haimiao Wu
- Department of Orthodontics, Shanghai Stomatological Hospital, Fudan University, No.356 Beijing East Road, Shanghai, China
| | - Bingjiao Zhao
- Department of Orthodontics, Shanghai Stomatological Hospital, Fudan University, No.356 Beijing East Road, Shanghai, China.
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25
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Chen SM, Huang TH, Ho CT, Kao CT. Force degradation study on aligner plates immersed in various solutions. J Dent Sci 2023; 18:1845-1849. [PMID: 37799905 PMCID: PMC10547977 DOI: 10.1016/j.jds.2023.06.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/18/2023] [Indexed: 10/07/2023] Open
Abstract
Background/purpose The strength of aligners themselves has a high decay rate and is susceptible to accelerated degradation in the environment. The purpose of this study was to compare three types of invisible aligner films after being immersed in coffee, tea, cola, and red wine for seven days and to evaluate the changes in their strengths. Materials and methods Three types of invisible aligner plates with a thickness of 0.75 mm, i.e., Duran T (polyethylene terephthalate glycol, PETG), Biolon (polyethylene terephthalate, PET), and Zendura FLX (polyurethane, PU), were soaked in artificial saliva and four drinks (coffee, tea, cola, red wine) for 1, 4, and 7 days. The strength test was performed by using the three-point bending test method. The residual strength ratio for the same type of invisible correction film at the same time was separately recorded. The independent t-test was used to indicate significant differences at P < 0.05. Results The Biolon invisible correction film soaked in cola, red wine and artificial saliva showed significant differences on the 1st and 4th days (P < 0.05). The Duran T invisible correction film soaked in coffee and artificial saliva showed significant differences on the first day (P < 0.05). The Zendura FLX invisible correction film had a waterproof layer on the surface, and there was no significant difference between soaking in any drink and soaking in saliva (P > 0.05). Conclusion Invisible correction films with different ingredients soaked in solutions show a strength decay phenomenon, except for those with TPU ingredients.
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Affiliation(s)
- Shou-Min Chen
- School of Dentistry, College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan
- Orthodontic Department, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Tsui-Hsein Huang
- School of Dentistry, College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan
- Dental Department, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Chun-Te Ho
- School of Dentistry, College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan
- Orthodontic Department, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Chia-Tze Kao
- Orthodontic Department, Chung Shan Medical University Hospital, Taichung, Taiwan
- Dental Department, Chung Shan Medical University Hospital, Taichung, Taiwan
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26
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Astasov-Frauenhoffer M, Göldi L, Rohr N, Worreth S, Dard E, Hünerfauth S, Töpper T, Zurflüh J, Braissant O. Antimicrobial and mechanical assessment of cellulose-based thermoformable material for invisible dental braces with natural essential oils protecting from biofilm formation. Sci Rep 2023; 13:13428. [PMID: 37596293 PMCID: PMC10439145 DOI: 10.1038/s41598-023-39320-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 07/23/2023] [Indexed: 08/20/2023] Open
Abstract
Controlling biofilm formation in the oral cavity during orthodontic treatments is crucial. Therefore, antimicrobial surfaces for invisible dental appliances are of interest to both therapists and patients. Here we present a cellulose-based thermoformable material used for invisible braces that can be loaded with essential oils (EOs) having antibacterial and antifungal properties. We hypothesize that this material can absorb and release EOs, thus providing an antimicrobial effect without compromising the safety and mechanical properties necessary for dental invisible braces. Conventional microbiology and isothermal microcalorimetry analyses revealed that the thermoformable material loaded with essential oils significantly delayed the biofilm formation of oral streptococci (S. mutans and S. mitis) under static conditions (p < 0.05) and while simulating saliva flow (p < 0.05). In addition, cytotoxicity tests (ISO 10993-5), revealed that the loaded material is well tolerated by human gingival fibroblasts. Finally, the loading with antibacterial agents did not significantly alter the mechanical properties and stability of the material (initial force (p = 0.916); initial stress (p = 0.465)). Compared to gold-standard clear aligner materials, this material offers a reliable transmission of forces for orthodontic treatments. Moreover, this approach exhibits the potential for acting as an oral drug delivery platform for multiple compounds.
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Affiliation(s)
- Monika Astasov-Frauenhoffer
- Department Research, University Center for Dental Medicine Basel UZB, University of Basel, Mattenstrasse 40, Basel, Switzerland
| | - Livia Göldi
- Department Research, University Center for Dental Medicine Basel UZB, University of Basel, Mattenstrasse 40, Basel, Switzerland
| | - Nadja Rohr
- Department Research, University Center for Dental Medicine Basel UZB, University of Basel, Mattenstrasse 40, Basel, Switzerland
| | - Sarah Worreth
- Department of Biomedical Engineering (DBE), Center of Biomechanics and Biocalorimetry, University of Basel, Allschwil, Switzerland
| | - Elise Dard
- Bottmedical AG Technologiepark Basel, Hochbergerstrasse 60C, 4057, Basel, Switzerland
| | - Selina Hünerfauth
- Bottmedical AG Technologiepark Basel, Hochbergerstrasse 60C, 4057, Basel, Switzerland
| | - Tino Töpper
- Bottmedical AG Technologiepark Basel, Hochbergerstrasse 60C, 4057, Basel, Switzerland
| | - Jonas Zurflüh
- Department Chemie, University of Basel, Mattenstrasse 24a, Basel, Switzerland
| | - Olivier Braissant
- Department of Biomedical Engineering (DBE), Center of Biomechanics and Biocalorimetry, University of Basel, Allschwil, Switzerland.
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Lira LF, Otero Amaral Vargas E, Moreira da Silva E, Nunes da Silva Meirelles Dória Maia J, Elzubair A, Siqueira de Morais L, Alvaro de Souza Camargo S, Serra G, Gomes de Souza MM. Effect of oral exposure on chemical, physical, mechanical, and morphologic properties of clear orthodontic aligners. Am J Orthod Dentofacial Orthop 2023; 164:e51-e63. [PMID: 37330727 DOI: 10.1016/j.ajodo.2023.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 05/01/2023] [Accepted: 05/01/2023] [Indexed: 06/19/2023]
Abstract
INTRODUCTION The dental industry is heavily committed to developing more esthetic solutions for orthodontic treatments. Invisalign is a system of transparent orthodontic aligners introduced as an alternative to conventional orthodontic fittings with brackets and metal wires. This study aimed to assess the chemical, physical, mechanical and morphologic changes in these polymeric aligners after exposure to the oral environment. METHODS Twenty-four Invisalign orthodontic aligners were equally divided into 2 groups: an in vivo aged group in which patients used aligners for 14 days and the reference group, unexposed to the oral environment. Different experimental techniques were used to study the chemical structure, the color changes and translucency, the density and subsequent volume of the aligners, mechanical properties, surface roughness, morphology and elemental composition. The data were subjected to several statistical analyses. RESULTS Clear orthodontic aligners exhibit chemical stability but undergo a statistically significant optical change in color and translucency. There was a gradual increase in the water absorption rate and the dimensional variation of the polymer, indicating a strong correlation among these factors. The mechanical properties of the polymer showed a statistically significant decrease in its elastic modulus and hardness. There was a slight tendency toward increased surface roughness of the material, but no statistical differences were found between reference and aged groups. The surface morphology of the used aligners demonstrates microcracks, distortions and biofilm formation. CONCLUSION Intraoral aging adversely affected the physical, mechanical, and morphologic properties of the Invisalign appliance.
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Affiliation(s)
- Larine Ferreira Lira
- Department of Pediatric Dentistry and Orthodontics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Eduardo Otero Amaral Vargas
- Department of Pediatric Dentistry and Orthodontics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Eduardo Moreira da Silva
- Analytical Laboratory of Restorative Biomaterials-LABiom-R, School of Dentistry, Federal Fluminense University, Niterói, Brazil
| | | | - Amal Elzubair
- Metallurgical and Materials Engineering Program, Alberto Luiz Coimbra Institute for Graduate Studies and Research in Engineering (COPPE), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Liliane Siqueira de Morais
- Department of Pediatric Dentistry and Orthodontics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Sérgio Alvaro de Souza Camargo
- Metallurgical and Materials Engineering Program, Alberto Luiz Coimbra Institute for Graduate Studies and Research in Engineering (COPPE), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Nanotechnology Engineering Program, COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Glaucio Serra
- Department of Specific Formation, Federal Fluminense University, Nova Friburgo, Brazil
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Yang F, Wu C, Jiang Y, Tan L, Shu R. Development of an antibacterial polypropylene/polyurethane composite membrane for invisible orthodontics application. Front Bioeng Biotechnol 2023; 11:1233398. [PMID: 37485323 PMCID: PMC10361250 DOI: 10.3389/fbioe.2023.1233398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 06/28/2023] [Indexed: 07/25/2023] Open
Abstract
In virtue of the advantages, such as aesthetics, designability, convenient removal, and comfortable experience, invisible orthodontics (IO) have been widely recognized and accepted by the public. However, most of the membranes currently used for IO only meet the requirement of shape retention. Other vital functions, like antibacterial and antifouling activities, are neglected. Herein, antibacterial composite membranes (ACMs) containing polypropylene (PP), thermoplastic polyurethane (TPU) and poly (hexamethylene guanidine) hydrochloride-sodium stearate (PHMG-SS) were facilely manufactured through the hot-pressing membrane forming technology. ACMs were conferred with favorable transparency (∼70% in the visible light range) and excellent antibacterial ability. Experiment results demonstrated that bactericidal rates of ACMs against Staphylococcus aureus, Escherichia coli and Streptococcus mutans were larger than 99.99%. Noticeably, the amount of protein adhered on the surface of ACMs was only 28.1 μg/cm2, showing ideal antifouling performance. Collectively, the mutifunctional ACMs in the study are expected to be prominent alternatives for existing IO.
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Affiliation(s)
- Feng Yang
- State Key Laboratory of Oral Diseases, Department of Pediatric Dentistry, West China School of Stomatology, Sichuan University, Chengdu, China
- State Key Laboratory of Polymer Materials Engineering, College of Biomass Science and Engineering, Sichuan University, Chengdu, China
- Research Center for Fiber Science and Engineering Technology, Yibin Institute of Industrial Technology, Sichuan University, Yibin, China
| | - Chenyi Wu
- State Key Laboratory of Oral Diseases, Department of Pediatric Dentistry, West China School of Stomatology, Sichuan University, Chengdu, China
| | - Yuanzhang Jiang
- State Key Laboratory of Polymer Materials Engineering, College of Biomass Science and Engineering, Sichuan University, Chengdu, China
- Research Center for Fiber Science and Engineering Technology, Yibin Institute of Industrial Technology, Sichuan University, Yibin, China
| | - Lin Tan
- State Key Laboratory of Polymer Materials Engineering, College of Biomass Science and Engineering, Sichuan University, Chengdu, China
- Research Center for Fiber Science and Engineering Technology, Yibin Institute of Industrial Technology, Sichuan University, Yibin, China
| | - Rui Shu
- State Key Laboratory of Oral Diseases, Department of Pediatric Dentistry, West China School of Stomatology, Sichuan University, Chengdu, China
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Elshazly TM, Nang D, Golkhani B, Elattar H, Keilig L, Bourauel C. Effect of thermomechanical aging of orthodontic aligners on force and torque generation: An in vitro study. J Mech Behav Biomed Mater 2023; 143:105911. [PMID: 37207526 DOI: 10.1016/j.jmbbm.2023.105911] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/10/2023] [Accepted: 05/14/2023] [Indexed: 05/21/2023]
Abstract
The aim of the study is to investigate the effects of artificial aging by thermocycling and mechanical loading on force/torque delivery by thermoplastic orthodontic aligners. Ten thermoformed aligners, made of Zendura™ thermoplastic polyurethane sheets, were aged over two weeks in deionized water by thermocycling alone (n = 5) and by both thermocycling and mechanical loading (n = 5). The force/torque generated on upper second premolar (Tooth 25) of a plastic model was measured before aging (as control), and after 2, 4, 6, 10, and 14 days of aging, using a biomechanical set-up. Before aging, the extrusion-intrusion forces were in the range of 2.4-3.0 N, the oro-vestibular forces were 1.8-2.0 N, and the torques on mesio-distal rotation were 13.6-40.0 Nmm. Pure thermocycling had no significant effect on the force decay of the aligners. However, there was a significant decrease in force/torque after 2 days of aging for both thermocycling and mechanical loading aging group, which is no longer significant over 14 days of aging. In conclusion, artificial aging of aligners in deionized water with both thermocycling and mechanical loading results in a significant decrease in force/torque generation. However, mechanical loading of aligners has a greater impact than pure thermocycling.
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Affiliation(s)
- Tarek M Elshazly
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany.
| | - Diva Nang
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany
| | - Bijan Golkhani
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany
| | - Hanaa Elattar
- Orthodontic Department, Faculty of Dentistry, Umm Al-Qura University, Makkah, Saudi Arabia; Orthodontic Department, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt
| | - Ludger Keilig
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany; Department of Dental Prosthetics, Propaedeutics and Materials Science, Dental School, University Hospital Bonn, Bonn, Germany
| | - Christoph Bourauel
- Oral Technology Department, Dental School, University Hospital Bonn, Bonn, Germany
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Spanier C, Schwahn C, Krey KF, Ratzmann A. Fused filament fabrication (FFF): influence of layer height on forces and moments delivered by aligners-an in vitro study. Clin Oral Investig 2023; 27:2163-2173. [PMID: 36790628 PMCID: PMC10159977 DOI: 10.1007/s00784-023-04912-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 02/03/2023] [Indexed: 02/16/2023]
Abstract
OBJECTIVES To investigate the effect of layer height of FFF-printed models on aligner force transmission to a second maxillary premolar during buccal torquing, distalization, extrusion, and rotation using differing foil thicknesses. MATERIALS AND METHODS Utilizing OnyxCeph3™ Lab (Image Instruments GmbH, Chemnitz, Germany, Release Version 3.2.185), the following movements were programmed for the second premolar: buccal torque (0.1-0.5 mm), distalization (0.1-0.4 mm), extrusion (0.1-0.4 mm), rotation (0.1-0.5 mm), and staging 0.1 mm. Via FFF, 91 maxillary models were printed for each staging at different layer heights (100 µm, 150 µm, 200 µm, 250 µm, 300 µm). Hence, 182 aligners, made of polyethylene terephthalate glycol (PET-G) with two thicknesses (0.5 mm and 0.75 mm), were prepared. The test setup comprised an acrylic maxillary model with the second premolar separated and mounted on a sensor, measuring initial forces and moments exerted by the aligners. A generalized linear model for the gamma distribution was applied, evaluating the significance of the factors layer height, type of movement, aligner thickness, and staging on aligner force transmission. RESULTS Foil thickness and staging were found to have a significant influence on forces delivered by aligners, whereas no significance was determined for layer height and type of movement. Nevertheless, at a layer height of 150 µm, the most appropriate force transmission was observed. CONCLUSIONS Printing aligner models at particularly low layer heights leads to uneconomically high print time without perceptible better force delivery properties, whereas higher layer heights provoke higher unpredictability of forces due to scattering. A z-resolution of 150 µm appears ideal for in-office aligner production combining advantages of economic print time and optimal force transmission.
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Affiliation(s)
- Claudia Spanier
- Department of Orthodontics and Craniofacial Orthopedics, University Medicine Greifswald, 17475, Greifswald, Germany
| | - Christian Schwahn
- Department for Prosthodontics, Gerostomatology and Biomaterials, University Medicine Greifswald, Greifswald, Germany
| | - Karl-Friedrich Krey
- Department of Orthodontics and Craniofacial Orthopedics, University Medicine Greifswald, 17475, Greifswald, Germany.
| | - Anja Ratzmann
- Department of Orthodontics and Craniofacial Orthopedics, University Medicine Greifswald, 17475, Greifswald, Germany
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Elkholy F, Schmidt S, Schmidt F, Amirkhani M, Lapatki BG. Force decay of polyethylene terephthalate glycol aligner materials during simulation of typical clinical loading/unloading scenarios. J Orofac Orthop 2023; 84:189-201. [PMID: 34882259 PMCID: PMC10119250 DOI: 10.1007/s00056-021-00364-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 10/28/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND This in vitro study investigated the effect of three distinct daily loading/unloading cycles on force delivery during orthodontic aligner therapy. The cycles were applied for 7 days and were designed to reflect typical clinical aligner application scenarios. MATERIALS AND METHODS Flat polyethylene terephthalate glycol (PET-G) specimens (Duran®, Scheu Dental, Iserlohn, Germany) with thicknesses ranging between 0.4 and 0.75 mm were tested in a three-point-bending testing machine. Measurements comprised loading/unloading intervals of 12 h/12 h, 18 h/6 h, and 23 h/1 h, and specimens were exposed to bidistilled water during loading to simulate intraoral conditions. RESULTS A very large decay in force for the PET‑G specimens could already be observed after the first loading period, with significantly different residual force values of 24, 20, and 21% recorded for the 12 h/12 h, 18 h/6 h, and 23 h/1 h loading/unloading modes, respectively (Mann-Whitney U test, p < 0.01). In addition, further decays in force from the first to the last loading period at day 7 of 13.5% (12 h/12 h), 9.7% (18 h/6 h), and 8.4% (23 h/1 h) differed significantly among the three distinct loading modes (Mann-Whitney U test, p < 0.01). CONCLUSION Although the initial material stiffness of PET‑G is relatively high, the transmission of excessive forces is attenuated by the high material-related force decay already within a few hours after intraoral insertion.
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Affiliation(s)
- Fayez Elkholy
- Department of Orthodontics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Silva Schmidt
- Department of Orthodontics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Falko Schmidt
- Department of Orthodontics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Masoud Amirkhani
- Institute of Experimental Physics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Bernd G. Lapatki
- Department of Orthodontics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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Shirey N, Mendonca G, Groth C, Kim-Berman H. Comparison of mechanical properties of 3-dimensional printed and thermoformed orthodontic aligners. Am J Orthod Dentofacial Orthop 2023; 163:720-728. [PMID: 37142355 DOI: 10.1016/j.ajodo.2022.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 12/01/2022] [Accepted: 12/01/2022] [Indexed: 05/06/2023]
Abstract
INTRODUCTION Orthodontic treatment using clear aligners has experienced exponential growth since its introduction in the late 1990s. Three-dimensional (3D) printing has also grown in popularity among orthodontists, and companies have begun to produce resins to directly print clear aligners. This study aimed to examine the mechanical properties of commercially available thermoformed aligners and direct 3D-printed aligners under laboratory conditions and a simulated oral environment. METHODS Samples were prepared (approximately 2.5 × 20 mm) from 2 thermoformed materials, EX30 and LD30 (Align Technology Inc, San Jose, Calif), as well as 2 direct 3D-printing resins, Material X (Envisiontec, Inc; Dearborn, Mich) and OD-Clear TF (3DResyns, Barcelona, Spain). Wet samples were subjected to phosphate-buffered saline at 37°C for 7 days, whereas dry samples were stored at 25°C. Tensile and stress relaxation tests were carried out on an RSA3 Dynamic Mechanical Analyzer (Texas Instruments, Dallas, Tex) and Instron Universal Testing System (Instron, Norwood, Mass) to calculate elastic modulus, ultimate tensile strength, and stress relaxation. RESULTS The elastic modulus of dry and wet samples was 103.2 ± 17.3 MPa and 114.4 ± 17.9 MPa (EX30), 61.3 ± 9.18 MPa and 103.5 ± 11.4 MPa (LD30), 431.2 ± 16.0 MPa and 139.9 ± 34.6 MPa (Material X), and 38.4 ± 14.7 MPa and 38.3 ± 8.4 MPa (OD-Clear TF), respectively. The ultimate tensile strength of dry and wet samples was 64.41 ± 7.25 MPa and 61.43 ± 7.41MPa (EX30), 40.04 ± 5.00 MPa and 30.09 ± 1.50 MPa (LD30), 28.11 ± 3.75 MPa and 27.57 ± 4.09 MPa (Material X), and 9.34 ± 1.96 MPa and 8.27 ± 0.93 MPa (OD-Clear TF), respectively. Residual stress of wet samples at 2% strain for 2 hours was 59.99 ± 3.02% (EX30), 52.57 ± 12.28% (LD30), 6.98 ± 2.64% (Material X), and 4.39 ± 0.84% (OD-Clear TF). CONCLUSIONS There was a significant difference in elastic modulus, ultimate tensile strength, and stress relaxation among the samples tested. Moisture, specifically a simulated oral environment, appears to have a greater effect on the mechanical properties of direct 3D-printed aligners when compared with thermoformed aligners. This is likely to impact the ability of 3D-printed aligners to generate and maintain adequate force levels for tooth movement.
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Affiliation(s)
- Nic Shirey
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, Mich.
| | - Gustavo Mendonca
- Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, Va
| | - Christian Groth
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, Mich
| | - Hera Kim-Berman
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, Mich
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Muro MP, Caracciolo ACA, Patel MP, Feres MFN, Roscoe MG. Effectiveness and predictability of treatment with clear orthodontic aligners: A scoping review. Int Orthod 2023; 21:100755. [PMID: 37086643 DOI: 10.1016/j.ortho.2023.100755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 04/24/2023]
Abstract
INTRODUCTION In an ideal clinical setting, orthodontic therapy with clear aligners (CA) should improve the patients' initial malocclusion and must guarantee equivalence between the results predicted and those obtained clinically to be considered an effective treatment. Therefore, this scoping review aimed to identify the orthodontic literature concerning the effectiveness and predictability of CA treatments. METHODS A systematic computerized search was performed in 3 databases: PubMed, Scopus, and Embase. Inclusion criteria selected observational and clinical studies performed in at least 10 adult orthodontic patients, whose results of CA treatment's effectiveness and/or predictability were assessed. RESULTS The 3 database computerized searches resulted in 1,553 articles, and 169 full texts were considered potentially relevant. After applying the eligibility criteria, 33 studies were included. Most studies (76%) were designed as cohort studies and have been published in the last 5 years (79%). The majority included only non-extraction treatments (73%), and 79% reported results achieved with the Invisalign® system. The most predictable movement was the buccolingual tipping, while the least predictable movements were rotation, intrusion, and extrusion. Aligner treatment was effective for mild to moderate crowding resolution, and the success of overbite correction still seems to be limited. CONCLUSIONS The studies have demonstrated improvement of initial malocclusion through CA treatments. Still, predictability degree is overestimated and does not accurately reflect the occlusion immediately at the end of treatment. In future studies, there should be an effort to broaden the utilization of alternative aligner systems beyond Invisalign® and broadly disseminate their outcomes to strengthen clear aligners evidence base.
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Affiliation(s)
| | | | - Mayara Paim Patel
- Dental Research Division, School of Dentistry, Guarulhos University, Guarulhos, São Paulo, Brazil
| | | | - Marina Guimarães Roscoe
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil
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Alam MK, Kanwal B, Shqaidef A, Alswairki HJ, Alfawzan AA, Alabdullatif AI, Aalmunif AN, Aljrewey SH, Alothman TA, Shrivastava D, Srivastava KC. A Systematic Review and Network Meta-Analysis on the Impact of Various Aligner Materials and Attachments on Orthodontic Tooth Movement. J Funct Biomater 2023; 14:jfb14040209. [PMID: 37103299 PMCID: PMC10141153 DOI: 10.3390/jfb14040209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/21/2023] [Accepted: 04/06/2023] [Indexed: 04/28/2023] Open
Abstract
The majority of patients strongly favor the use of aligners in the present time, especially with the advancement in esthetic dentistry. Today's market is flooded with aligner companies, many of which share the same therapeutic ethos. We therefore carried out a systematic review and network meta-analysis to evaluate research that had looked at various aligner materials and attachments and their effect on orthodontic tooth movement in relevant studies. A total of 634 papers were discovered after a thorough search of online journals using keywords such as "Aligners", "Orthodontics", "Orthodontic attachments", "Orthodontic tooth movement", and "Polyethylene" across databases such as PubMed, Web of Science, and Cochrane. The authors individually and in parallel carried out the database investigation, removal of duplicate studies, data extraction, and bias risk. The statistical analysis demonstrated that the type of aligner material had a significant impact on orthodontic tooth movement. The low level of heterogeneity and significant overall effect further support this finding. However, there was little effect of attachment size or shape on tooth mobility. The examined materials were primarily concerned with influencing the physical/physicochemical characteristics of the appliances and not tooth movement directly. Invisalign (Inv) had a higher mean value than the other types of materials that were analyzed, which suggested a potentially greater impact on orthodontic tooth movement. However, its variance value indicated that there was also greater uncertainty associated with the estimate compared to some of the other plastics. These findings could have important implications for orthodontic treatment planning and aligner material selection. Registration: This review protocol was registered on the International Prospective Register of Systematic Reviews (PROSPERO; registration number: CRD42022381466).
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Affiliation(s)
- Mohammad Khursheed Alam
- Orthodontic Division, Preventive Dentistry Department, College of Dentistry, Jouf University, Sakaka 72345, Saudi Arabia
- Department of Dental Research Cell, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Chennai 602105, India
- Department of Public Health, Faculty of Allied Health Sciences, Daffodil lnternational University, Dhaka 1216, Bangladesh
| | - Bushra Kanwal
- Practicing in Dental Clinic, Al Baha 65511, Saudi Arabia
| | - Abedalrahman Shqaidef
- Department of Clinical Sciences, Center of Medical and Bio-Allied Health Sciences Research, College of Dentistry, Ajman University, Ajman 346, United Arab Emirates
| | | | - Ahmed Ali Alfawzan
- Department of Preventive Dentistry, College of Dentistry in Ar Rass, Qassim University, Ar Rass 52571, Saudi Arabia
| | | | | | | | | | - Deepti Shrivastava
- Periodontics Division, Preventive Dentistry Department, College of Dentistry, Jouf University, Sakaka 72345, Saudi Arabia
| | - Kumar Chandan Srivastava
- Oral Medicine & Maxillofacial Radiology Division, Department of Oral & Maxillofacial Surgery & Diagnostic Sciences, College of Dentistry, Jouf University, Sakaka 72345, Saudi Arabia
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Bichu YM, Alwafi A, Liu X, Andrews J, Ludwig B, Bichu AY, Zou B. Advances in orthodontic clear aligner materials. Bioact Mater 2023; 22:384-403. [PMID: 36311049 PMCID: PMC9588987 DOI: 10.1016/j.bioactmat.2022.10.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/24/2022] Open
Abstract
Rapid technological improvements in biomaterials, computer-aided design (CAD) and manufacturing (CAM) have endorsed clear aligner therapy (CAT) as a mainstay of orthodontic treatment, and the materials employed for aligner fabrication play an all-important role in determining the clinical performance of clear aligners. This narrative review has attempted to comprehensively encompass the entire gamut of materials currently used for the fabrication of clear aligners and elucidate their characteristics that are crucial in determining their performance in an oral environment. Historical developments and current protocols in aligner fabrication, features of contemporary bioactive materials, and emerging trends related to CAT are discussed. Advances in aligner material chemistry and engineering possess the potential to bring about radical transformations in the therapeutic applications of CAT; in the absence of which, clear aligners would continue to underperform clinically, due to their inherent biomechanical constraints. Finally, while innovations in aligner materials such as shape memory polymers, direct three-dimensional (3D) printed clear aligners and bioactive materials combined with clear aligner materials are essential to further advance the applications of CAT; increased awareness of environmental responsibilities among aligner manufacturers, aligner prescribing clinicians and aligner users is essential for better alignment of our climate change goals towards a sustainable planet.
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Affiliation(s)
| | - Abdulraheem Alwafi
- Department of Oral Health Science, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
- Faculty of Dentistry, Department of Dental Public Health, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Xiaomo Liu
- Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China
| | | | - Björn Ludwig
- Department of Orthodontics, University of Homburg, Saar, Germany
| | | | - Bingshuang Zou
- Department of Oral Health Science, Faculty of Dentistry, University of British Columbia, Vancouver, Canada
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Quinzi V, Orilisi G, Vitiello F, Notarstefano V, Marzo G, Orsini G. A spectroscopic study on orthodontic aligners: First evidence of secondary microplastic detachment after seven days of artificial saliva exposure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 866:161356. [PMID: 36603638 DOI: 10.1016/j.scitotenv.2022.161356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/20/2022] [Accepted: 12/30/2022] [Indexed: 06/17/2023]
Abstract
Clear orthodontic aligners have recently seen increasing popularity. The thermoplastic materials present several advantages, even if it is known that all plastic products can be subjected to environmental and mechanical degradation, leading to the release of microplastics (MPs). Their ingestion could cause oxidative stress and inflammatory lesions. This study aims to evaluate the potential detachment of MPs by clear aligners due to mechanical friction simulated with a 7-day protocol in artificial saliva. The study was performed on orthodontic clear aligners from different manufacturers: Alleo (AL); FlexiLigner (FL); F22 Aligner (F22); Invisalign® (INV); Lineo (LIN); Arc Angel (ARC), and Ortobel Aligner (OR). For each group, two aligners were immersed in artificial saliva for 7 days and stirred for 5 h/day, simulating the physiological teeth mechanical friction. After 7 days, the artificial saliva was filtered; then, filters were analyzed by Raman Microspectroscopy (RMS) and Scanning Electron Microscopy (SEM), respectively to chemically identify the polymeric matrix and to measure the number and size of the detected MPs. RMS spectra revealed that AL, FL, LIN, ARC, and OR aligners were composed by polyethylene terephthalate, while F22 and INV ones by polyurethane. SEM analysis showed that the highest number of MPs was found in ARC and the lowest in INV (p < 0.05). As regards MPs' size, no statistically significant difference was found among groups, with most MPs ranging from 5 to 20 μm. Noteworthy, a highly significant correlation (p < 0.0001) was highlighted between the distribution of MPs size and the different typologies of aligners. This in vitro study highlighted for the first time the detachment of MPs from clear aligners due to mechanical friction. This evidence may represent a great concern in the clinical practice since it could impact human general health.
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Affiliation(s)
- Vincenzo Quinzi
- Università degli Studi dell'Aquila, Dipartimento di Medicina Clinica, Sanità Pubblica, Scienze della Vita e dell'Ambiente, Piazza Salvatore Tommasi, 67100 L'Aquila, Italy
| | - Giulia Orilisi
- Università Politecnica delle Marche, Dipartimento di Scienze Cliniche Specialistiche ed Odontostomatologiche, Via Tronto 10, 60126 Ancona, Italy
| | - Flavia Vitiello
- Università Politecnica delle Marche, Dipartimento di Scienze Cliniche Specialistiche ed Odontostomatologiche, Via Tronto 10, 60126 Ancona, Italy
| | - Valentina Notarstefano
- Università Politecnica delle Marche, Dipartimento di Scienze della Vita e dell'Ambiente, Via Brecce Bianche, 60131 Ancona, Italy
| | - Giuseppe Marzo
- Università degli Studi dell'Aquila, Dipartimento di Medicina Clinica, Sanità Pubblica, Scienze della Vita e dell'Ambiente, Piazza Salvatore Tommasi, 67100 L'Aquila, Italy
| | - Giovanna Orsini
- Università Politecnica delle Marche, Dipartimento di Scienze Cliniche Specialistiche ed Odontostomatologiche, Via Tronto 10, 60126 Ancona, Italy.
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Grünheid T, Bitner TF. Wear and fatigue resistance: An in-vitro comparison of three polyethylene terephthalate glycol and thermoplastic polyurethane materials for vacuum-formed retainers. Int Orthod 2023; 21:100748. [PMID: 36934632 DOI: 10.1016/j.ortho.2023.100748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/27/2023] [Accepted: 03/04/2023] [Indexed: 03/19/2023]
Abstract
OBJECTIVE To test the wear and fatigue resistance of three materials (Essix ACE®, Taglus®, and Zendura A®) for the fabrication of vacuum-formed retainers in an artificial oral environment. MATERIAL AND METHODS Wear resistance was tested by subjecting 21 retainers of each Essix ACE®, Taglus®, and Zendura A® to 12,000 wear cycles at 75N to simulate one year of retainer wear with moderate nighttime bruxing. Post-wear retainer thickness was compared to baseline measurements to calculate wear depth. Fatigue resistance was tested by flexing 15 retainers of each material at an angle of 25 degrees for 1,825 cycles to simulate one year of removing and reinserting a retainer five times per day. Retainers were visually inspected for fractures. Pairwise t-tests with correction using Tukey's method were used to determine significant differences between materials. RESULTS The mean wear depths were 0.155±0.021mm, 0.168±0.031mm, and 0.096±0.033mm for Essix ACE®, Taglus®, and Zendura A®, respectively. The wear depth of Zendura A® was significantly lower than that of both Essix ACE® (P<0.001) and Taglus® (P<0.001). There was no significant difference in wear depth between Essix ACE® and Taglus® (P=0.312). Under the parameters set for the fatigue resistance test, fractures did not occur on any of the tested materials. CONCLUSIONS Under the assumption of moderate nighttime bruxing for one year, Zendura A® is the most wear-resistant among the materials tested. With the assumption of retainer removal and reinsertion five times per day for one year, all three materials tested have the same ability to resist fatigue.
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Affiliation(s)
- Thorsten Grünheid
- Division of Orthodontics, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA.
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Goracci C, Juloski J, D’Amico C, Balestra D, Volpe A, Juloski J, Vichi A. Clinically Relevant Properties of 3D Printable Materials for Intraoral Use in Orthodontics: A Critical Review of the Literature. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16062166. [PMID: 36984045 PMCID: PMC10058724 DOI: 10.3390/ma16062166] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/01/2023] [Accepted: 03/07/2023] [Indexed: 06/05/2023]
Abstract
The review aimed at analyzing the evidence available on 3D printable materials and techniques used for the fabrication of orthodontic appliances, focusing on materials properties that are clinically relevant. MEDLINE/PubMed, Scopus, and Cochrane Library databases were searched. Starting from an initial retrieval of 669 citations, 47 articles were finally included in the qualitative review. Several articles presented proof-of-concept clinical cases describing the digital workflow to manufacture a variety of appliances. Clinical studies other than these case reports are not available. The fabrication of aligners is the most investigated application of 3D printing in orthodontics, and, among materials, Dental LT Clear Resin (Formlabs) has been tested in several studies, although Tera Harz TC-85 (Graphy) is currently the only material specifically marketed for direct printing of aligners. Tests of the mechanical properties of aligners materials lacked homogeneity in the protocols, while biocompatibility tests failed to assess the influence of intraoral conditions on eluents release. The aesthetic properties of 3D-printed appliances are largely unexplored. The evidence on 3D-printed metallic appliances is also limited. The scientific evidence on 3D printable orthodontic materials and techniques should be strengthened by defining international standards for laboratory testing and by starting the necessary clinical trials.
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Affiliation(s)
- Cecilia Goracci
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
| | - Jovana Juloski
- Department of Orthodontics, School of Dental Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Claudio D’Amico
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
| | - Dario Balestra
- School of Dental Medicine, Alfonso X El Sabio University, 28691 Madrid, Spain
| | - Alessandra Volpe
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
| | - Jelena Juloski
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
- Clinic for Paediatric and Preventive Dentistry, School of Dental Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Alessandro Vichi
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK
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Venkatasubramanian P, Jerome MS, Ragunanthanan L, Maheshwari U, Vijayalakshmi D. Color stability of aligner materials on exposure to indigenous food products: An in-vitro study. J Dent Res Dent Clin Dent Prospects 2022; 16:221-228. [PMID: 37560499 PMCID: PMC10407867 DOI: 10.34172/joddd.2022.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 12/03/2022] [Indexed: 08/11/2023] Open
Abstract
Background In the recent day, there has been an exponential growth in the usage of clear aligners for orthodontic treatment. As with any removable appliance, the compliance of patients to remove it during ingestion of food is, at times, poor. Thus, the stability of the clear aligner to be "clear" becomes questionable. This in-vitro study examined how the clear aligners changed colour on exposure to various indigenous food products used in everyday life. Methods Aligners from 5 different companies (K Line, Clearbite Aligners, The Aligner Company, iAligners and MaxDent CA Digital) were exposed for 12 hours and 24 hours to various indigenous substances (tea, green tea, coffee, turmeric, saffron and Kashmiri red chili powder) and a control solution (distilled water) in-vitro. The color change was assessed with the help of VITA Easyshade compact colorimeter based on Commission Internationale de I'Eclairage L*a*b* color system. Values were then modified to NBS units for clinical relevance. Results The hue of the transparent aligners was noticed to change in a statistically meaningful way when exposed to turmeric, saffron, Kashmiri red chili powder and coffee in decreasing order and mild color change in tea and green tea at both 12 hours and 24 hours intervals. Conclusion Aligners are prone to color change when exposed to indigenous foods that contain staining properties.
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Affiliation(s)
- Priyanka Venkatasubramanian
- Department of Orthodontics and Dentofacial Orthopaedics, Meenakshi Ammal Dental College and Hospital, Meenakshi Academy of Higher Education & Research, Mylapore, Chennai, India
| | - Mary Sanjana Jerome
- Department of Orthodontics and Dentofacial Orthopaedics, Meenakshi Ammal Dental College and Hospital, Meenakshi Academy of Higher Education & Research, Mylapore, Chennai, India
| | - Lokamithra Ragunanthanan
- Department of Orthodontics and Dentofacial Orthopaedics, Meenakshi Ammal Dental College and Hospital, Meenakshi Academy of Higher Education & Research, Mylapore, Chennai, India
| | - Uma Maheshwari
- Department of Orthodontics and Dentofacial Orthopaedics, Meenakshi Ammal Dental College and Hospital, Meenakshi Academy of Higher Education & Research, Mylapore, Chennai, India
| | - Devaki Vijayalakshmi
- Department of Orthodontics and Dentofacial Orthopaedics, Meenakshi Ammal Dental College and Hospital, Meenakshi Academy of Higher Education & Research, Mylapore, Chennai, India
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Liu JQ, Zhu GY, Wang YG, Zhang B, Wang SC, Yao K, Zhao ZH. Different biomechanical effects of clear aligners in bimaxillary space closure under two strong anchorages: finite element analysis. Prog Orthod 2022; 23:41. [DOI: 10.1186/s40510-022-00435-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 08/18/2022] [Indexed: 11/15/2022] Open
Abstract
Abstract
Background
Clear aligner (CA) treatment has been gaining popularity, but the biomechanical effects of CAs in bimaxillary dentition have not been thoroughly investigated. Direct and indirect strong anchorages are two common anchorage control methods, but the underlying biomechanical mechanism has not yet been elucidated. This study aimed to investigate the different biomechanical effects of CAs in closing the bimaxillary space under different anchorage controls, further instructing the compensation strategies design and strong anchorage choice in clinical practice.
Methods
Three-dimensional (3D) bimaxillary models of different anchorage controls were created based on cone-beam computed tomography and intraoral scan data. Four first premolars were extracted using 3D modeling software. Finite element analysis was conducted to simulate the space closure process of the CAs.
Results
In the two strong anchorage groups, the bimaxillary dentition presented different movement patterns during the space closure process, and the lower dentition was more vulnerable to elastic force. From the vertical view, direct strong anchorage with elastic force had the advantage of flattening the longitudinal occlusal curve and resisting the roller-coaster effects, whereas indirect strong anchorage could lead to a deep longitudinal occlusal curve. From the sagittal view, indirect strong anchorage with metallic ligaments had a greater instantaneous anchorage protection effect, particularly in the lower dentition, which reduced the mesial movement of the posterior teeth by nearly four times that of the direct anchorage group. In addition, indirect strong anchorage presented better anterior teeth torque/tipping control, while direct strong anchorage could aggravate lingual tipping of the upper central incisors. Due to the differences in anterior–posterior anchorage and arch shape, compared with the upper dentition, anchorage preservation and vertical control effects were amplified in the lower dentition.
Conclusions
The biomechanical effects of CAs differed between the two strong anchorage groups. Due to the differences in dentition morphology, anterior–posterior anchorage, and dental arch shape, CAs present different biomechanical effects in bimaxillary space closure. Orthodontists should consider the corresponding mechanical compensation according to specific anchorage control methods and dentitions.
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41
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Wu E. The application of in-office aligners in the combination treatment protocol. Semin Orthod 2022. [DOI: 10.1053/j.sodo.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Albertini P, Mazzanti V, Mollica F, Pellitteri F, Palone M, Lombardo L. Stress Relaxation Properties of Five Orthodontic Aligner Materials: A 14-Day In-Vitro Study. Bioengineering (Basel) 2022; 9:bioengineering9080349. [PMID: 36004874 PMCID: PMC9405504 DOI: 10.3390/bioengineering9080349] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/25/2022] [Accepted: 07/27/2022] [Indexed: 11/16/2022] Open
Abstract
We aimed to investigate the stress relaxation properties of five different thermoplastic aligner materials subjected to 14 days of constant deflection. Five different thermoplastic aligner materials were selected, whose elastic properties varied: F22 Evoflex, F22 Aligner, Durasoft, Erkoloc-Pro and Duran. The static properties of these materials—in particular, stiffness, stress–strain curve and yield stress—were measured with a three-point bending test. For all the tests that were performed, a minimum of three samples per material were tested. The yield load, yield strength, deformation and particularly the stiffness of each material were found to be similar in the single-layer samples, while the double-layer samples showed far lower stiffness values and were similar one to another. F22 Evoflex and Erkoloc-Pro maintained the highest percentages of stress, 39.2% and 36.9%, respectively, during the 15-day period. Duran and Durasoft obtained the lowest final stress values, 0.5 MPa and 0.4 MPa, respectively, and the lowest percentage of normalized stress, 4.6% and 3.9%, respectively, during the 15-day period. All the materials that we tested showed a rapidity of stress decay during the first few hours of application, before reaching a plateau phase. The F22 Evoflex material showed the greatest level of final stress, with relatively constant stress release during the entire 15-day period. Further research after in vivo aging is necessary in order to study the real aligners’ behavior during orthodontic treatment.
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Affiliation(s)
- Paolo Albertini
- Department of Orthodontics, University of Ferrara, Via Luigi Borsari, 46, 44121 Ferrara, Italy; (F.P.); (M.P.); (L.L.)
- Correspondence: ; Tel.: +39-3486649586
| | - Valentina Mazzanti
- Department of Engineering, University of Ferrara, 44121 Ferrara, Italy; (V.M.); (F.M.)
| | - Francesco Mollica
- Department of Engineering, University of Ferrara, 44121 Ferrara, Italy; (V.M.); (F.M.)
| | - Federica Pellitteri
- Department of Orthodontics, University of Ferrara, Via Luigi Borsari, 46, 44121 Ferrara, Italy; (F.P.); (M.P.); (L.L.)
| | - Mario Palone
- Department of Orthodontics, University of Ferrara, Via Luigi Borsari, 46, 44121 Ferrara, Italy; (F.P.); (M.P.); (L.L.)
| | - Luca Lombardo
- Department of Orthodontics, University of Ferrara, Via Luigi Borsari, 46, 44121 Ferrara, Italy; (F.P.); (M.P.); (L.L.)
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Casavola C, Pappalettera G, Pappalettere C, Patronelli M, Renna G, Laurenziello M, Ciavarella D. A full-field DIC analysis of the mechanical-deformation behavior of polyethylene terephthalate glycol (PET-G) aligners. J Mech Behav Biomed Mater 2022; 134:105391. [PMID: 35930946 DOI: 10.1016/j.jmbbm.2022.105391] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/15/2022] [Accepted: 07/17/2022] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The aim was to investigate the full-field mechanical-deformation behavior of clear aligners made by polyethylene terephthalate glycol (PET-G) subjected to cyclic compression tests. METHODS Digital Image Correlation (DIC) (Chu et al., 1985; Schreier et al., 2009), a contactless full-field measurement technique, and Optical Microscope (OM) analysis were applied to study two PET-G aligners thermoformed from discs of a thickness of 0.75 mm and 0.88 mm. The clear aligners were placed on dental shape resin casts and were subjected to cyclic compression up to 13000 load cycles from 0 to 50 N at room temperature. The chosen number of load cycles simulates the average load history to which an aligner is subjected for one week. Local displacements and strains were measured for each test at 2, 6, 10, 20, 1000, 5000 and 13000 loading cycles. RESULTS Both aligners showed greater displacements in the early stages of loading, more pronounced for the 0.88 mm one. Local displacement and strain maps are derived both along the load direction and to the transverse one (never done from other researchers). Load-displacement cyclic curves allowed to evaluate the evolution of the stored energy and the stiffness during the test. The OM analyses showed significant morphological variations on the aligners' surface, such as wear and tear, high depressions and cracks, especially for the 0.75 mm specimen. SIGNIFICANCE Full-field analysis allowed to understand the mechanical behavior of device with complex geometry and complex load distribution, like invisible aligners. The knowledge of the stiffness and the direction of the total displacement helps the orthodontist to implement the best strategy to improve the patient's comfort and the treatment time.
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Affiliation(s)
- Caterina Casavola
- Politecnico di Bari, Dipartimento di Meccanica Matematica e Management, Via Orabona 4, 70125, Bari, Italy
| | - Giovanni Pappalettera
- Politecnico di Bari, Dipartimento di Meccanica Matematica e Management, Via Orabona 4, 70125, Bari, Italy
| | - Carmine Pappalettere
- Politecnico di Bari, Dipartimento di Meccanica Matematica e Management, Via Orabona 4, 70125, Bari, Italy
| | - Marika Patronelli
- Politecnico di Bari, Dipartimento di Meccanica Matematica e Management, Via Orabona 4, 70125, Bari, Italy.
| | - Gilda Renna
- Politecnico di Bari, Dipartimento di Meccanica Matematica e Management, Via Orabona 4, 70125, Bari, Italy
| | - Michele Laurenziello
- Università di Foggia, Dipartimento di Medicina Sperimentale e Clinica, Via Gramsci 89/91, 71122, Foggia, Italy
| | - Domenico Ciavarella
- Università di Foggia, Dipartimento di Medicina Sperimentale e Clinica, Via Gramsci 89/91, 71122, Foggia, Italy
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Perrotti G, Carrafiello A, Rossi O, Karanxha L, Baccaglione G, Del Fabbro M. Clinical Use of Aligners Associated with Nuvola ® OP System for Transverse Maxillary Deficiency: A Retrospective Study on 100 Patients. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19095751. [PMID: 35565146 PMCID: PMC9103427 DOI: 10.3390/ijerph19095751] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/05/2022] [Accepted: 05/07/2022] [Indexed: 01/26/2023]
Abstract
Introduction: Aligners represent a common treatment for orthodontic patients thanks to their countless advantages including aesthetics, comfort, and oral hygiene maintenance; at the same time, they are associated with a reduced number of visits and a low incidence of complications. Although aligners have undergone considerable improvements over time, to date they have limitations in resolving the most serious malocclusions related to transverse maxillary deficiency. The aim of the present study was to retrospectively evaluate an orthodontic protocol (the Nuvola® OP System) which associates a morpho-functional corrector (to be used for 30 min/day) with the aligner, allowing for the treatment of cases that would be difficult or unpredictable with aligners alone. Methods: Linear measurements were taken on STL files of 100 patients. In 77 patients between 18 and 55 years (mean 28.6 ± 16.2 (standard deviation) years), 3D superimpositions of the maxilla obtained from intraoral scans before and after treatment were performed in order to evaluate the degree of maxillary expansion. The normality of the data distribution was tested. The pre- and post-treatment data were compared using a paired t-test with a 5% significance level. After treatment, a questionnaire was proposed to assess patients’ degree of satisfaction and compliance. Results: A statistically significant difference (p < 0.05) for each distance evaluated was found. The maximum expansion was obtained at the first molar level (2.35 ± 1.64 mm). Of the subjects who completed the questionnaire, 96% were satisfied and 90% were able to perform the protocol without difficulty for the required duration. Conclusions: A significant expansion of the maxillary arch as well as a high degree of patient satisfaction and compliance were observed with the Nuvola® OP System. Further studies are needed in order to clinically evaluate the relative contribution of the aligners and morpho-functional device to the obtained expansion.
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Affiliation(s)
| | | | - Ornella Rossi
- Lake Como Institute, 22100 Como, Italy; (G.P.); (O.R.)
| | - Lorena Karanxha
- Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, 20122 Milano, Italy;
| | | | - Massimo Del Fabbro
- Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, 20122 Milano, Italy;
- IRCCS Orthopedic Institute Galeazzi, Via Riccardo Galeazzi 4, 20161 Milan, Italy
- Correspondence: ; Tel.: +39-02-50319950; Fax: +39-02-50319960
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45
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Kwok M, Porto B, Mohebi S, Zhu L, Hans M. Physical and chemical properties of five different clear thermoplastic materials. J Appl Polym Sci 2022. [DOI: 10.1002/app.51957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Man‐Hin Kwok
- Department of Macromolecular Science and Engineering Case Western Reserve University Cleveland Ohio USA
| | - Betina Porto
- Department of Orthodontics, School of Dental Medicine Case Western Reserve University Cleveland Ohio USA
| | - Shadi Mohebi
- Department of Orthodontics, School of Dental Medicine Case Western Reserve University Cleveland Ohio USA
| | - Lei Zhu
- Department of Macromolecular Science and Engineering Case Western Reserve University Cleveland Ohio USA
| | - Mark Hans
- Department of Orthodontics, School of Dental Medicine Case Western Reserve University Cleveland Ohio USA
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46
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Lee SY, Kim H, Kim HJ, Chung CJ, Choi YJ, Kim SJ, Cha JY. Thermo-mechanical properties of 3D printed photocurable shape memory resin for clear aligners. Sci Rep 2022; 12:6246. [PMID: 35428796 PMCID: PMC9012852 DOI: 10.1038/s41598-022-09831-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 03/14/2022] [Indexed: 11/22/2022] Open
Abstract
To overcome the limitations of the conventional vacuum thermoforming manufacturing method, direct 3D printing of clear aligners has been developed. The present study investigated the thermo-mechanical and viscoelastic properties of a photocurable resin TC-85, which is a new material for the direct 3D printed clear aligners, comparing to a conventional thermoplastic material polyethylene terephthalate glycol. Dynamic mechanical analysis was performed to analyse the mechanical behaviours of the two materials at 37 °C and 80 °C, respectively. Furthermore, the shape memory property of the two materials was evaluated using a U-shape bending test, and the shape recovery ratio for 60 min at 37 °C was calculated. The results indicate that TC-85 can constantly apply a light force to the teeth when used for the 3D printed clear aligners, owing to its flexibility and viscoelastic properties. In addition, it is expected that the force decay induced by repeated insertion of the clear aligners will be reduced and a constant orthodontic force will be maintained. Furthermore, its geometric stability at high temperatures and the shape memory properties provide advantages for the clinical application.
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Affiliation(s)
- Se Yeon Lee
- Department of Orthodontics, College of Dentistry, Yonsei University, Seoul, Korea
| | - Hoon Kim
- Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Korea.,Graphy Inc., Graphy R&D Center, Seoul, Korea
| | - Hyun-Joong Kim
- Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Korea.,Laboratory of Adhesion and Bio-Composites, Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul, Korea
| | - Chooryung J Chung
- Department of Orthodontics, Gangnam Severance Hospital, Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea
| | - Yoon Jeong Choi
- Department of Orthodontics, Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Su-Jung Kim
- Department of Orthodontics, Kyung Hee University School of Dentistry, Seoul, Korea
| | - Jung-Yul Cha
- Department of Orthodontics, Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea.
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47
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Takara Y, Haga S, Kimura H, Maki K. Mechanical analysis of factors affecting clear aligner removability. Dent Mater J 2022; 41:534-544. [PMID: 35321972 DOI: 10.4012/dmj.2021-176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
It is difficult to control corrective forces in orthodontic treatment with clear aligners. The grip of aligners on teeth is important to ensure accurate corrective forces from aligners. This study aimed to measure the gripping force of aligners under various conditions to clarify factors that influence it. We created aligners with different attachment morphologies and placement sites and different margin lengths. We developed a device to measure the mechanics involved in the removal of these aligners. The gripping force was evaluated at five different aligner removal sites on the teeth. We found that the gripping force of the aligner was the weakest on the lingual side of the first molar and strongest on the labial side of the central incisors and that the attachment morphology and placement sites affected the gripping force of aligners.
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Affiliation(s)
- Yurie Takara
- Department of Orthodontics, School of Dentistry, Showa University
| | - Shugo Haga
- Department of Orthodontics, School of Dentistry, Showa University
| | - Hitoshi Kimura
- Department of Engineering Design, Tamagawa University College of Engineering
| | - Koutaro Maki
- Department of Orthodontics, School of Dentistry, Showa University
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48
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Jia L, Wang C, Wang C, Song J, Fan Y. Efficacy of various multi-layers of orthodontic clear aligners: a simulated study. Comput Methods Biomech Biomed Engin 2022; 25:1710-1721. [PMID: 35188858 DOI: 10.1080/10255842.2022.2034796] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND In the invisible orthodontic treatment, composite thermoforming film materials have become the focus of orthodontic clear aligners. The orthodontic efficacy of clear aligners which consisted of multi-layers materials remains unclear. This study aims to evaluate the biomechanical effects of various multi-layers of clear aligners on en-mass retraction of maxillary anterior teeth. METHODS A patient-specific 3D non-linear finite element model numerical analysis was constructed to simulate the en-mass retraction of maxillary anterior teeth with clear aligner after extraction of the first premolars. Four kinds of multi-layers clear aligners with different proportion of film materials were simulated. The biomechanical responses of four different clear aligners on invisible orthodontics were calculated. The tooth displacement in all directions, the hydrostatic pressure of periodontal ligament, the orthodontic deformation of clear aligner, and the stress distribution of alveolar bone were compared and investigated. RESULTS In all experimental models, the maximum equivalent deformation of alveolar bone, the vector displacement of tooth and the compressive/tensile stress of periodontal ligament decreased with the increase of soft layer thickness. The elastic strain of clear aligners also decreased with the increase of the ratio of soft/hard layers. CONCLUSIONS The multi-layers clear aligner is better than the single-layer clear aligner in tooth movement, stress distribution of periodontal ligament and mechanical loading of alveolar bone, especially when the ratio of soft layer to hard layer is more than 50%. Moreover, the side effects of the multi-layers clear aligner are significantly less than those of the single-layer one.
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Affiliation(s)
- Lurong Jia
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China.,Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Chunjuan Wang
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China.,Stomatological Hospital of Chongqing Medical University, Chongqing, China
| | - Chao Wang
- Stomatological Hospital of Chongqing Medical University, Chongqing, China.,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China.,Key Laboratory for Biomechanics and Mechanobiology (Beihang University), Ministry of Education, 100191 Beijing, China
| | - Jinlin Song
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing, China.,Stomatological Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, China
| | - Yubo Fan
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China.,Key Laboratory for Biomechanics and Mechanobiology (Beihang University), Ministry of Education, 100191 Beijing, China
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49
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Performance of Rigid and Soft Transfer Templates Using Viscous and Fluid Resin-Based Composites in the Attachment Bonding Process of Clear Aligners. Int J Dent 2022; 2022:1637594. [PMID: 35190741 PMCID: PMC8858075 DOI: 10.1155/2022/1637594] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 01/09/2022] [Accepted: 01/17/2022] [Indexed: 12/17/2022] Open
Abstract
Objectives The study aims at assessing the accuracy of the process of attachment bonding in aligner treatments. The analysis leads to the error estimation in the faithful reproduction of master model attachments using two types of transfer templates and two light-curing resin-based composites usually used in orthodontics. Methods The authors have used two transfer templates made of two different materials. The first, named Leone-biocompatible thermoforming material hard/soft, has a lower Young's modulus and is labelled as soft, while the other, named Leone-biocompatible thermoforming material, is marked as rigid. The resin-based composites possess different mechanical and rheological properties. Specifically, Transbond™ XT Light Cure Paste Adhesive, 3M has a higher viscosity than the TetricEvoflow, Ivoclar Vivadent, a flowable nanohybrid composite. The authors attempt to estimate the performance ranking between the four possible couples obtained by combining the two light-curing resin-based composites and transfer templates. Each combination was repeated in six models and compared with twelve master models, resulting in 36 total samples. A 3-D laser scanner is used to generate a digital model of each model. The comparison between digital models is the base for a comparative assessment in terms of relative and absolute error. The relative error is estimated using scalar performance indicators ranging from 0 to 1, where 1 indicates the optimum matching. The absolute error estimated from the mean square error between the coordinates of each digital model yields the reproduction accuracy in micrometer. Furthermore, the authors attempted to assess the error distribution by evaluating the point-by-point difference between the digital models. Results This analysis aims at localizing the sources of error in the considered models. The use of Transbond™ XT Light Cure Paste Adhesive, 3M with a rigid transfer template is always associated with significant accuracy and minor dispersion. However, in a few instances, using the soft template or the flowable resin-based composite can lead to bad performances. Significance. The data processing bestowed the following performance ranking from the first with lower reproduction error to the last characterized by the worst performance: (1) attachments bonding with rigid template and Transbond™ XT Light Cure Paste Adhesive, 3M, (2) attachments bonding with soft template and Transbond™ XT Light Cure Paste Adhesive, 3M, (3) attachments bonding with rigid template and TetricEvoflow, Ivoclar Vivadent, and (4) attachments bonding with soft template and TetricEvoflow, Ivoclar Vivadent.
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50
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Amit Vijay K, Manoj Ranjan M. Trust-based secure routing in IoT network based on rider foraging optimization algorithm. JOURNAL OF HIGH SPEED NETWORKS 2022. [DOI: 10.3233/jhs-220680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Due to the mobility and frequent topology changes, routing the data poses a challenging issue in the Internet of Things (IoT). Security poses a fundamental requirement factor in most IoT applications particularly, secure routing among the IoT nodes. The aim of this paper is to develop secure routing in IoT with minimal delay, minimal energy consumption and high throughput. Thus, a new algorithm, named Rider Foraging Optimization algorithm (RFO) is designed by the incorporation of standard Rider Optimization algorithm (ROA) and Bacterial Foraging optimization algorithm (BFO) that render an optimal solution, which is the optimal path for transmitting the information. Initially, the trust of the nodes is evaluated and the cluster head (CH) is chosen based on Low-Energy Adaptive Clustering Hierarchy (LEACH) protocol to securely transmit the data. Then, the proposed RFO algorithm selects the optimal path using the fitness factors, such as trust, energy, and delay constraints. The results revealed that the energy consumption of the nodes is reduced and the lifetime of the network is enhanced through the implementation of the proposed RFO, which attained a maximal throughput of 1, and minimal delay and energy consumption of 0.1169 and 0.0002, respectively.
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Affiliation(s)
- Kore Amit Vijay
- Research Scholar, KIIT, Deemed to be University, Patia, Bhubaneswar, Odisha 751024, India. E-mail:
| | - Mishra Manoj Ranjan
- School of Computer Application, KIIT, Deemed to be University, Patia, Bhubaneswar, Odisha 751024, India. E-mail:
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