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Kaur H, Khurelbaatar T, Mah J, Heo G, Major PW, Romanyk DL. In vitro biomechanics of divot use, and their placement, in orthodontic aligner therapy. Orthod Craniofac Res 2024; 27:527-534. [PMID: 38299945 DOI: 10.1111/ocr.12760] [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] [Accepted: 01/16/2024] [Indexed: 02/02/2024]
Abstract
INTRODUCTION To evaluate biomechanics of an aligner utilizing divots and the effect of their vertical placement on the right maxillary central incisor. METHODS An in vitro Orthodontic SIMulator (OSIM) was used to test forces and moments generated by aligners incorporating divots. The OSIM arch was scanned to generate a. STL version that was modified to create four models by placing divots on different positions of the right central maxillary incisor: GI - divots on gingival-third of lingual surface and incisal-third of labial surface; GM - divots on gingival-third of lingual surface and middle-third of labial surface; MI - divots on middle-third of lingual surface and incisal-third of labial surface; MM - divots on middle-third of lingual surface and middle-third of labial surface. Aligners (n = 30/model) were fabricated using a 0.75 mm thick polyethylene terephthalate material and Biostar® machine following the manufacturer's recommendations. A one-way MANOVA followed by one-way ANOVA (α = 0.05) was utilized to test effect of models on buccolingual force (Fy) and mesiodistal moment (Mx) at 0.20 mm of lingual displacement of the right maxillary central incisor. RESULTS Mean Mx for GI (-5.68 ± 7.38 Nmm), GM (3.75 ± 5.54 Nmm), MI (-4.27 ± 1.48 Nmm) and MM (1.96 ± 0.99 Nmm) models showed statistical differences between GI and GM, GI and MM, GM and MI and MI and MM. GI exerted the largest Fy (1.87 ± 0.75 N) followed by GM (1.10 ± 0.47 N), MI (0.70 ± 0.23 N) and MM (0.28 ± 0.08 N) with significant differences between GI and GM, GI and MI, GI and MM and GM and MM models. CONCLUSIONS Vertical divot placement on a right central incisor had a significant effect on aligner biomechanics. Buccolingual forces exerted by models GI, GM and MI were within the range suggested by literature for bodily tooth movement without major root tipping for GM and MI models.
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Affiliation(s)
- Harsimrat Kaur
- Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Tsolmonbaatar Khurelbaatar
- Faculty of Engineering - Mechanical Engineering Department, University of Alberta, Edmonton, Alberta, Canada
| | - James Mah
- School of Dental Medicine, University of Nevada, Las Vegas, Nevada, USA
| | - Giseon Heo
- Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Paul W Major
- Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Dan L Romanyk
- Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Faculty of Engineering - Mechanical Engineering Department, University of Alberta, Edmonton, Alberta, Canada
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Ravuri P, Kubavat AK, Rathi V, Luke John T, Varma PK, Mujoo S, Somaraj V. Effectiveness and Biocompatibility of Tooth Aligners Made from Polyethylene Terephthalate Glycol (PeT-G), Polypropylene (PP), Polycarbonate (PC), Thermoplastic Polyurethanes (TPUs), and Ethylene-Vinyl Acetate (EVA): A Systematic Review. JOURNAL OF PHARMACY AND BIOALLIED SCIENCES 2024; 16:S93-S96. [PMID: 38595485 PMCID: PMC11001044 DOI: 10.4103/jpbs.jpbs_883_23] [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: 09/12/2023] [Revised: 09/19/2023] [Accepted: 09/23/2023] [Indexed: 04/11/2024] Open
Abstract
Objective This systematic review examines the efficacy and biocompatibility of orthodontic clear aligner tooth aligners constructed from polyethylene terephthalate glycol (PeT-G), polypropylene (PP), polycarbonate (PC), thermoplastic polyurethanes (TPUs), and ethylene-vinyl acetate (EVA). Materials and Methods To find relevant papers published through September 2021, PubMed was searched extensively. Randomized clinical trials (RCTs) and observational studies assessing the effectiveness and biocompatibility of the aligner materials were included. Data were extracted independently, and the quality of included research was appraised using relevant procedures. The research variability necessitated a narrative synthesis. Results Five studies were included for comparison. All materials were biocompatible; however, PeT-G and EVA aligners caused the least tissue irritation. Patients preferred TPU aligners for initial comfort and PeT-G aligners for transparency and endurance. Conclusion Biocompatible PeT-G, PP, PC, TPU, and EVA tooth aligners fix malocclusions. Aligner materials should be chosen based on patient preferences, treatment goals, and material qualities. For stronger proof, a longer-term study is needed.
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Affiliation(s)
- Preetham Ravuri
- Department of Orthodontics and Dentofacial Orthopedics, Narsinhbhai Patel Dental College and Hospital, Sankalchand Patel University, Visnagar, Gujarat, India
| | - Ajay K. Kubavat
- Department of Orthodontics and Dentofacial Orthopedics, Narsinhbhai Patel Dental College and Hospital, Sankalchand Patel University, Visnagar, Gujarat, India
| | - Vipul Rathi
- Department of Orthodontics and Dentofacial Orthopedics, VYWS Dental College and Hospital, Amravati, Maharashtra, India
| | - T. Luke John
- Department of Orthodontics and Dentofacial Orthopeadics, Anil Neerukonda Institute of Dental Sciences, Sangivalasa, Visakhapatnam, Andhra Pradesh, India
| | - Praveen K. Varma
- Department of Orthodontics, Vishnu Dental College, Vishnupur, Bhimavaram, Andhra Pradesh, India
| | - Sheetal Mujoo
- Division of Oral Medicine and Radiology, College of Dentistry, Jazan University, Jazan, Saudi Arabia
| | - Vinej Somaraj
- Department of Public Health Dentistry, Rajas Dental College and Hospital, Tirunelveli, Tamil Nadu, India
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Narongdej P, Hassanpour M, Alterman N, Rawlins-Buchanan F, Barjasteh E. Advancements in Clear Aligner Fabrication: A Comprehensive Review of Direct-3D Printing Technologies. Polymers (Basel) 2024; 16:371. [PMID: 38337260 DOI: 10.3390/polym16030371] [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: 12/26/2023] [Revised: 01/25/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Clear aligners have revolutionized orthodontic treatment by offering an esthetically driven treatment modality to patients of all ages. Over the past two decades, aligners have been used to treat malocclusions in millions of patients worldwide. The inception of aligner therapy goes back to the 1940s, yet the protocols to fabricate aligners have been continuously evolved. CAD/CAM driven protocol was the latest approach which drastically changed the scalability of aligner fabrication-i.e., aligner mass production manufacturing. 3D printing technology has been adopted in various sectors including dentistry mostly because of the ability to create complex geometric structures at high accuracy while reducing labor and material costs-for the most part. The integration of 3D printing in dentistry has been across, starting in orthodontics and oral surgery and expanding in periodontics, prosthodontics, and oral implantology. Continuous progress in material development has led to improved mechanical properties, biocompatibility, and overall quality of aligners. Consequently, aligners have become less invasive, more cost-effective, and deliver outcomes comparable to existing treatment options. The promise of 3D printed aligners lies in their ability to treat malocclusions effectively while providing esthetic benefits to patients by remaining virtually invisible throughout the treatment process. Herein, this review aims to provide a comprehensive summary of studies regarding direct-3D printing of clear aligners up to the present, outlining all essential properties required in 3D-printed clear aligners and the challenges that need to be addressed. Additionally, the review proposes implementation methods to further enhance the effectiveness of the treatment outcome.
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Affiliation(s)
- Poom Narongdej
- Department of Mechanical and Aerospace Engineering, California State University Long Beach, Long Beach, CA 90840, USA
- Institute of Mathematical Sciences, Claremont Graduate University, Claremont, CA 91711, USA
| | - Mana Hassanpour
- Department of Chemical Engineering, California State University Long Beach, Long Beach, CA 90840, USA
| | - Nicolas Alterman
- Department of Mechanical and Aerospace Engineering, California State University Long Beach, Long Beach, CA 90840, USA
| | | | - Ehsan Barjasteh
- Department of Mechanical and Aerospace Engineering, California State University Long Beach, Long Beach, CA 90840, USA
- Department of Chemical Engineering, California State University Long Beach, Long Beach, CA 90840, USA
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Bellocchio AM, Portelli M, Ciraolo L, Ciancio E, Militi A, Peditto M, Barbera S, Nucera R. Evaluation of the Clinical Variables Affecting Attachment Reproduction Accuracy during Clear Aligner Therapy. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6811. [PMID: 37895792 PMCID: PMC10607942 DOI: 10.3390/ma16206811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/09/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023]
Abstract
BACKGROUND The purpose of this study was to evaluate some of the clinical variables that influence the accuracy of reproducing the planned attachment shape. The following clinical variables were considered: the template material, type of composite, and pressure application on the template during attachment curing. METHODS In this study, the evaluated materials for the thermoplastic transfer template construction are Erkolen 0.8 (polyethylene: PE) and Erkodur 0.8 (polyethylene terephthalate glycol-PET-G), and two types of composite resins: Enaflow (light-curing low-viscosity composite resin) and Enamel plus dentina HRI (light-curing high-viscosity composite resin). Two different light-curing lamps were used: Valo cordless color with no pressure and push light pressure (SCS). The 26 models included in the study were imported into the 3 Shape Ortho System 2022 (ver. 85.0.20 3 Shape, Denmark), and attachments were virtually placed on the dental elements of the first premolar and on both sides of the first upper molars. The accuracy of the attachment reproduction was evaluated through linear and angular evaluations against the reference model (MCAD). Three physical models were obtained: model A (MA), which was printed with attachments; model B (MB) with attachments made with a PE template; and model C (MC) with attachments made with a PET-G template. RESULTS The results showed statistically significant differences (p < 0.05) between the PE and PET-G templates with greater precision using the PET-G template. Statistically significant differences (p < 0.05) were found among the high-viscosity composite and low-viscosity composite with pressure curing. CONCLUSIONS In light of the obtained data, using a PET-G template is recommended. The pressure application during composite curing reduces the reproduction accuracy with a low-viscosity composite.
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Affiliation(s)
- Angela Mirea Bellocchio
- Department of Biomedical Sciences, Dentistry and Morphological and Functional Imaging, University of Messina, Via Consolare Valeria 1, 98125 Messina, Italy; (M.P.); (L.C.); (E.C.); (A.M.); (M.P.); (S.B.); (R.N.)
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Schönfeld D, Koss S, Vohl N, Friess F, Drescher D, Pretsch T. Dual Stimuli-Responsive Orthodontic Aligners: An In Vitro Study. MATERIALS (BASEL, SWITZERLAND) 2023; 16:3094. [PMID: 37109929 PMCID: PMC10145520 DOI: 10.3390/ma16083094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/03/2023] [Accepted: 04/05/2023] [Indexed: 06/19/2023]
Abstract
Aligner therapy for orthodontic tooth movement is gaining importance in orthodontics. The aim of this contribution is to introduce a thermo- and water-responsive shape memory polymer (SMP), which could lay the foundation for a new type of aligner therapy. The thermal, thermo-mechanical, and shape memory properties of thermoplastic polyurethane were studied by means of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and various practical experiments. The glass transition temperature of the SMP relevant for later switching was determined to be 50 °C in the DSC, while the tan δ peak was detected at 60 °C in the DMA. A biological evaluation was carried out using mouse fibroblast cells, which showed that the SMP is not cytotoxic in vitro. On a digitally designed and additively manufactured dental model, four aligners were fabricated from an injection-molded foil using a thermoforming process. The aligners were then heated and placed on a second denture model which had a malocclusion. After cooling, the aligners were in a programmed shape. The movement of a loose, artificial tooth and thus the correction of the malocclusion could be realized by thermal triggering the shape memory effect, at which the aligner corrected a displacement with an arc length of approximately 3.5 mm. The developed maximum force was separately determined to be about 1 N. Moreover, shape recovery of another aligner was realized within 20 h in 37 °C water. In perspective, the present approach can help to reduce the number of orthodontic aligners in therapy and thus avoid excessive material waste.
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Affiliation(s)
- Dennis Schönfeld
- Fraunhofer Institute for Applied Polymer Research IAP, Geiselbergstr. 69, 14476 Potsdam, Germany
| | - Samantha Koss
- Department of Orthodontics, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Nils Vohl
- Department of Orthodontics, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Fabian Friess
- Fraunhofer Institute for Applied Polymer Research IAP, Geiselbergstr. 69, 14476 Potsdam, Germany
| | - Dieter Drescher
- Department of Orthodontics, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Thorsten Pretsch
- Fraunhofer Institute for Applied Polymer Research IAP, Geiselbergstr. 69, 14476 Potsdam, Germany
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