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Bauer CAJ, Scheurer M, Bourauel C, Kretzer JP, Roser CJ, Lux CJ, Hodecker LD. Precision of slot widths and torque transmission of in-office 3D printed brackets : An in vitro study. J Orofac Orthop 2024; 85:327-339. [PMID: 36862188 PMCID: PMC11358261 DOI: 10.1007/s00056-023-00460-8] [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: 05/24/2022] [Accepted: 12/29/2022] [Indexed: 03/03/2023]
Abstract
PURPOSE To investigate a novel in-office three-dimensionally (3D) printed polymer bracket regarding slot precision and torque transmission. METHODS Based on a 0.022″ bracket system, stereolithography was used to manufacture brackets (N = 30) from a high-performance polymer that met Medical Device Regulation (MDR) IIa requirements. Conventional metal and ceramic brackets were used for comparison. Slot precision was determined using calibrated plug gages. Torque transmission was measured after artificial aging. Palatal and vestibular crown torques were measured from 0 to 20° using titanium-molybdenum (T) and stainless steel (S) wires (0.019″ × 0.025″) in a biomechanical experimental setup. The Kruskal-Wallis test with post hoc test (Dunn-Bonferroni) was used for statistical analyses (significance level p < 0.05). RESULTS The slot sizes of all three bracket groups were within the tolerance range according to DIN 13996 (ceramic [C]: 0.581 ± 0.003 mm; metal [M]: 0.6 ± 0.005 mm; polymer [P]: 0.581 ± 0.010 mm). The maximum torque values of all bracket-arch combinations were above the clinically relevant range of 5-20 Nmm (PS: 30 ± 8.6 Nmm; PT: 27.8 ± 14.2 Nmm; CS: 24 ± 5.6 Nmm; CT: 19.9 ± 3.8 Nmm; MS: 21.4 ± 6.7 Nmm; MT: 16.7 ± 4.6 Nmm). CONCLUSIONS The novel, in-office manufactured polymer bracket showed comparable results to established bracket materials regarding slot precision and torque transmission. Given its high individualization possibilities as well as enabling an entire in-house supply chain, the novel polymer brackets bear high potential of future usage for orthodontic appliances.
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Affiliation(s)
- Carolien A J Bauer
- Poliklinik für Kieferorthopädie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany.
| | - Mats Scheurer
- Klinik und Poliklinik für Mund‑, Kiefer‑, Gesichtschirurgie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - Christoph Bourauel
- Oralmedizinische Technologie, Zentrum für Zahn‑, Mund- und Kieferheilkunde, Universitätsklinikum Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany
| | - J Philippe Kretzer
- Labor für Biomechanik und Implantatforschung, Klinik für Orthopädie, Universitätsklinikum Heidelberg, Schlierbacher Landstraße 200a, 69118, Heidelberg, Germany
| | - Christoph J Roser
- Poliklinik für Kieferorthopädie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - Christopher J Lux
- Poliklinik für Kieferorthopädie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
| | - Lutz D Hodecker
- Poliklinik für Kieferorthopädie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
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Bhardwaj A, Mishra K, Pandey A, Kirtiwar D, Kharche A, Agaldiviti P. Mechanical Properties of 3D Printed Orthodontic Aligners Produced by Different Commercially Available Printers - An In-Vitro Study. JOURNAL OF PHARMACY AND BIOALLIED SCIENCES 2024; 16:S1431-S1432. [PMID: 38882783 PMCID: PMC11174344 DOI: 10.4103/jpbs.jpbs_796_23] [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: 08/28/2023] [Revised: 09/15/2023] [Accepted: 09/25/2023] [Indexed: 06/18/2024] Open
Abstract
The aim of this study was to compare the mechanical properties of orthodontic aligners among different commercially available 3D printing devices. Three different 3D printers were included in this study (Formlabs Form 2 3D printer; Moonray S100 printer (Sprintray, Los Angeles, CA, USA); Eden500V Stratasys 3D Printers were used to prepare orthodontic aligners with dental. The central incisors of each aligner were cut, prepared, and evaluated in terms of Martens-Hardness (HM), indentation-modulus (EIT), and elastic-index (ηIT) as per ISO14577-1:2002. Post hoc pairwise comparisons indicated no significant difference in Martens-Hardness (HM), indentation-modulus (EIT), and elastic-index (ηIT) properties in any group. Under the limitations of this study, it may be concluded that the mechanical properties of 3D-printed orthodontic aligners are dependent on the 3D printer used, and thus, differences in their clinical efficacy are anticipated.
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Affiliation(s)
- Amit Bhardwaj
- Department of Orthodontics, Modern Dental College and Research Centre, Gandhi Nagar, Indore, Madhya Pradesh, India
| | - Kratika Mishra
- Department of Orthodontics and Dentofacial Orthopedics, Index Institute of Dental Sciences, Indore, Madhya Pradesh, India
| | - Ankita Pandey
- Department of Orthodontics and Dentofacial Orthopedics, Index Institute of Dental Sciences, Indore, Madhya Pradesh, India
| | | | - Asmita Kharche
- Department of Orthodontics and Dentofacial Orthopedics, Dr. D. Y. Patil Dental College, Dr. D. Y. Patil Vidyapeeth, Pune, Maharashtra, India
| | - Prashanth Agaldiviti
- Department of Orthodontics, Tirumala Institute of Dental Sciences, Bardipur (v), Ditchpally (M), Nizamabad, Telangana, India
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Anh NV, Son TM, Ngoc VTN, Anh NT. Management of moderate crowding by two-arch distalization using passive self-ligating lingual brackets, in-house digital indirect bonding, and mini-screw anchorage: A case report. APOS TRENDS IN ORTHODONTICS 2023. [DOI: 10.25259/apos_6_2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
This case report presents the management of an adult patient with moderate crowding in both arches and anterior crossbite with passive self-ligating lingual brackets. The orthodontic setup and bracket positioning was done digitally with an in-house approach. Virtual setup and bracket placement was performed on Autolign software (Diorco, Gyeonggi-do, Korea). The indirect bonding trays were vacuum-formed on printed malocclusion models with resin brackets. Two palatal and two buccal shelf miniscrews were used for two-arch distalization to correct proclined incisors and anterior open bite after leveling and alignment stage. After 12-month treatment, normal overbite,overjet and well-aligned dentition were achieved without premolar extraction. The incisors were uprighted slightly and the protrusive lower lip was retracted with improvement of facial harmony. One-year retention records confirmed that the outcome was stable. In-house digital setup and bracket placement could be a cost-effective approach for indirect lingual bracket bonding. Two-arch distalization with miniscrew anchorage may have the possibility of managing moderate crowding cases without premolar extraction or interproximal stripping.
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Graf S, Thakkar D, Hansa I, Pandian SM, Adel SM. 3D Metal Printing in Orthodontics Current Trends, Biomaterials, Workflows and Clinical Implications. Semin Orthod 2023. [DOI: 10.1053/j.sodo.2023.01.001] [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: 01/20/2023]
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Deeming G, Cobourne MT. Some thoughts on Invisalign. J Orthod 2022; 49:491-494. [DOI: 10.1177/14653125221135677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Guy Deeming
- Queensway Orthodontics, Teesside, Billingham, UK
| | - Martyn T. Cobourne
- Centre for Craniofacial & Regenerative Biology, King’s College London, London, UK
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Zinelis S, Polychronis G, Papadopoulos F, Kokkinos C, Economou A, Panayi N, Papageorgiou SN, Eliades T. Mechanical and electrochemical characterization of 3D printed orthodontic metallic appliances after in vivo ageing. Dent Mater 2022; 38:1721-1727. [PMID: 36123188 DOI: 10.1016/j.dental.2022.09.002] [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: 05/12/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVES Three-dimensional (3D) printing technology is a promising technique for fabricating custom orthodontic metallic appliances. Aim of this study was to assess the effect of intraoral aging on the mechanical / electrochemical properties of 3D-printed orthodontic metallic appliances. METHODS Twelve molar orthodontic distalization appliances 3D-printed from cobalt chromium (Co-Cr) alloy were retrieved after intraoral use and twenty blocks fabricated under similar conditions were used as control. The samples' microstructural / elemental composition assessment was assessed with SEM/EDS, while their mechanical properties (modulus of elasticity [EIT], Martens hardness [HM] and the elastic index [ηIT]) were measured by instrumented indentation testing. Finally, the samples' electrochemical features were assessed with a potentiostat-connected cell arrangement in terms of open circuit potential (OCP), corrosion potential (Ez), current density (I300) and breaking potential (Epit). Results were analyzed by t-test / Mann-Whitney test (α = 0.05). RESULTS The used Co-Cr alloy was found to have a highly homogenous structure with no significant differences between retrieved and new specimens in HM (4037.7 ± 215.6 vs 4090.9 ± 259.8 N/mm2), EIT (120.0 ± 13.2 vs 123.8 ± 12.9 GPa), or nIT (28.4 ± 2.6 vs 28.6 ± 2.9 %) (P > 0.05 in all instances). Metallic surfaces retained the same oxidation tendency and oxide dissolution rate in passive region in both groups (P > 0.05 for OCP, Ez, and I300). However, intraorally-aged specimens had a significantly lower breakdown potential due to degraded protection efficacy of surface oxide (P = 0.003 for Epit). SIGNIFICANCE The tested 3D-printed Co-Cr orthodontic appliances present clinically-acceptable mechanical properties that remained unaffected by intraoral ageing, which however degraded the protection of surface oxide against pitting corrosion.
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Affiliation(s)
- Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Polychronis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Frixos Papadopoulos
- Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Christos Kokkinos
- Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Anastasios Economou
- Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Nearchos Panayi
- Department of Dentistry, European University Cyprus, Nicosia, Cyprus; Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Spyridon N Papageorgiou
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
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Pratsinis H, Papageorgiou SN, Panayi N, Iliadi A, Eliades T, Kletsas D. Cytotoxicity and estrogenicity of a novel 3-dimensional printed orthodontic aligner. Am J Orthod Dentofacial Orthop 2022; 162:e116-e122. [PMID: 35842359 DOI: 10.1016/j.ajodo.2022.06.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 06/06/2022] [Accepted: 06/06/2022] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Orthodontic aligners printed with in-office 3-dimensional (3D) procedures have been described, but no data on their biocompatibility exist. This study investigates the cytotoxicity and estrogenicity of a 3D-printed orthodontic aligner by assessing its biological and behavioral effects. METHODS Ten sets of 1 type of aligner were immersed in sterile deionized water for 14 days, and the cytotoxicity and estrogenicity of released factors were assessed via MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assays on human gingival fibroblasts and the estrogen-sensitive MCF-7 and the estrogen-insensitive MDA-MB-231 breast cancer cell lines. 17β-Estradiol and bisphenol-A were used as positive controls. The statistical analysis of data was performed with generalized linear models at a 0.05 level of significance. RESULTS No signs of cytotoxicity were seen for the aligner samples for concentrations (v/v) of 20% (P = 0.32), 10% (P = 0.79), or 5% (P = 0.76). The antioxidant activity expressed as the capacity to reduce intracellular levels of reactive oxygen species was not affected in the aligner samples (P = 0.08). No significant estrogenicity was induced by the aligner samples compared with eluents from the negative control for both MCF-7 (P = 0.65) and MDA-MB-231 (P = 0.78). As expected, 17β-Estradiol and bisphenol-A stimulated MCF-7 cell proliferation, whereas no effect was observed on MDA-MB-231 cells. CONCLUSIONS In conclusion, if any factors were released during the 14-day aging of 3D-printed aligners in water, these were not found to be cytotoxic for human gingival fibroblasts and did not affect their intracellular reactive oxygen species levels. Moreover, no estrogenic effects of these putative eluates were observed based on an E-screen assay.
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Affiliation(s)
- Harris Pratsinis
- Laboratory of Cell Proliferation and Ageing, Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos," Athens, Greece
| | - Spyridon N Papageorgiou
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Nearchos Panayi
- Department of Dentistry, European University Cyprus, Nicosia, Cyprus; Private practice, Limassol, Cyprus
| | - Anna Iliadi
- Department of Dental Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
| | - Dimitris Kletsas
- Laboratory of Cell Proliferation and Ageing, Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos," Athens, Greece
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Utilization of a 3D Printed Orthodontic Distalizer for Tooth-Borne Hybrid Treatment in Class II Unilateral Malocclusions. MATERIALS 2022; 15:ma15051740. [PMID: 35268969 PMCID: PMC8911017 DOI: 10.3390/ma15051740] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/17/2022] [Accepted: 02/21/2022] [Indexed: 12/10/2022]
Abstract
This paper introduces a novel method of 3D designing and 3D printing of a hybrid orthodontic tooth-borne personalized distalizer for treatment of unilateral Class II malocclusion. Research objectives were to clinically utilize 3D printed distalizers, appraise feasibility of this technique and compare two different biocompatible photopolymers (white and transparent). Frequency of distalizers’ debonding and patients’ aesthetical perception was evaluated on the set of 12 complete orthodontic treatments. The mean duration of treatment period with a bonded distalizer was 6.4 months. All cases were adults with unilateral Class II malocclusion managed with a hybrid approach as a part of Invisalign® comprehensive treatment. Results showed that such perspective practice is feasible for 3D design and in-office 3D printing of a personalized distalizer. Results also showed no clinically significant differences between both studied biopolymers. The paper discusses an evaluation of such personalized distalizer functionality with regard to the current state of the art and compares to conventional prefabricated alternatives like a Carriere® Distalizer™ appliance. Research showed a preference of patients towards transparent biocompatible photopolymer instead of the white A2 shade. The paper concludes that additive manufacturing from dental resins is a viable method in personalization and in-office 3D printing of orthodontic auxiliaries, particularly distalizers. New materials for orthodontic 3D printing endow enhanced individualization, thus more efficient treatment.
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Papageorgiou SN, Polychronis G, Panayi N, Zinelis S, Eliades T. New aesthetic in-house 3D-printed brackets: proof of concept and fundamental mechanical properties. Prog Orthod 2022; 23:6. [PMID: 35187595 PMCID: PMC8859019 DOI: 10.1186/s40510-022-00400-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/10/2022] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVES Three-dimensional (3D) printing technology is an emerging manufacturing process for many orthodontic appliances, and the aim of this study was to evaluate the mechanical properties of resin-based materials as alternatives for the in-house preparation of orthodontic brackets. MATERIAL AND METHODS Two types of 3D printed resins used for temporary (T) and permanent (P) crown fabrication were included in this study. Ten blocks from each resin were manufactured by a 3D printer and, after embedding them in acrylic resin, the samples were subjected to metallographic grinding and polishing, followed by instrumented indentation testing (IIT). Martens hardness (HM), indentation modulus (EIT), and elastic index (ηIT) were determined with a Vickers indenter recording force-indentation depth curves from each specimen. After calculating descriptive statistics, differences between material types were investigated with Wilcoxon rank sum test accounting for clustering of measurements within specimens at alpha = 5%. RESULTS No statistically significant differences in the mechanical properties of the two tested materials were seen: HM: median 279 N/mm2 (interquartile range [IQR] 275-287 N/mm2) for T and median 279 N/mm2 (IQR 270-285 N/mm2) for P (P value = 0.63); EIT: median 5548 MPa (IQR 5425-5834 MPa) for T and median 5644 (IQR 5420-5850 MPa) for P (P value = 0.84); ηIT: median 47.1% (46.0-47.7%) for T and median 46.0% (IQR 45.4-47.8%) for P (P value = 0.24). CONCLUSIONS Under the limitations of this study, it may be concluded that the mechanical properties of the two 3D printed resins tested are equal, and thus, no differences in their clinical performance are expected.
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Affiliation(s)
- Spyridon N Papageorgiou
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
| | - Georgios Polychronis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Nearchos Panayi
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
- Department of Dentistry, European University Cyprus, Nicosia, Cyprus
| | - 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 of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland.
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Zinelis S, Panayi N, Polychronis G, Papageorgiou SN, Eliades T. Comparative analysis of mechanical properties of orthodontic aligners produced by different contemporary 3D printers. Orthod Craniofac Res 2021; 25:336-341. [PMID: 34569692 PMCID: PMC9544566 DOI: 10.1111/ocr.12537] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The aim of this study was to compare the mechanical properties of orthodontic aligners among different commercially available 3D printing devices. MATERIALS AND METHODS Five 3D printers (Ka:rv LP 550, Swinwon; "KAR"), (L120, Dazz 3D; "L12"), (MiiCraft 125, Miicraft Jena; "MIC"), (Slash 2, Uniz; "SLS") and (Pro 95, SprintRay; "PRO") were used to prepare orthodontic aligners with dental resin (Tera Harz TC-85DAW, Graphy). The central incisors of each aligner were cut, prepared and evaluated in terms of Martens-Hardness (HM), indentation-modulus (EIT ) and elastic-index (ηIT ) as per ISO14577-1:2002. Force-indentation curves were recorded and differences among printers were checked with generalized linear regressions (alpha=5%). RESULTS Statistically significant differences were seen for all mechanical properties (P < .05), which were in descending order: HM (N/mm2 ) as median (Interquartile Range [IQR]): SLS 108.5 (106.0-112.0), L12 103.0 (102.0-107.0), KAR 101.5 (97.5-103.0), MIC 100.0 (97.5-101.5) and PRO 94.0 (93.0-96.0); EIT (MPa) as mean (Standard Deviation [SD]): SLS 2696.3 (124.7), L12 2627.8 (73.5), MIC 2566.2 (125.1), KAR 2565.0 (130.2) and PRO 2491.2 (53.3); and ηIT (%) as median (IQR): SLS 32.8 (32.3-33.1), L12 31.6 (30.8-32.3), KAR 31.3 (30.9-31.9), MIC 30.5 (29.9-31.2) and PRO 29.5 (29.1-30.0). Additionally, significant differences existed between liquid crystal display (LCD) and digital light processing (DLP) printers for HM (P < .001), EIT (P = .002) and ηIT (P < .001), with aligners from the former having higher values than aligners from the latter printer. CONCLUSION Under the limitations of this study, it may be concluded that the mechanical properties of 3D-printed orthodontic aligners are dependent on the 3D printer used, and thus, differences in their clinical efficacy are anticipated.
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Affiliation(s)
- Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Georgios Polychronis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Spyridon N Papageorgiou
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
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Koletsi D, Iliadi A, Eliades T. Predictability of rotational tooth movement with orthodontic aligners comparing software-based and achieved data: A systematic review and meta-analysis of observational studies. J Orthod 2021; 48:277-287. [PMID: 34176358 PMCID: PMC8385585 DOI: 10.1177/14653125211027266] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To evaluate all available evidence on the prediction of rotational tooth movements with aligners. DATA SOURCES Seven databases of published and unpublished literature were searched up to 4 August 2020 for eligible studies. DATA SELECTION Studies were deemed eligible if they included evaluation of rotational tooth movement with any type of aligner, through the comparison of software-based and actually achieved data after patient treatment. DATA EXTRACTION AND DATA SYNTHESIS Data extraction was done independently and in duplicate and risk of bias assessment was performed with the use of the QUADAS-2 tool. Random effects meta-analyses with effect sizes and their 95% confidence intervals (CIs) were performed and the quality of the evidence was assessed through GRADE. RESULTS Seven articles were included in the qualitative synthesis, of which three contributed to meta-analyses. Overall results revealed a non-accurate prediction of the outcome for the software-based data, irrespective of the use of attachments or interproximal enamel reduction (IPR). Maxillary canines demonstrated the lowest percentage accuracy for rotational tooth movement (three studies: effect size = 47.9%; 95% CI = 27.2-69.5; P < 0.001), although high levels of heterogeneity were identified (I2: 86.9%; P < 0.001). Contrary, mandibular incisors presented the highest percentage accuracy for predicted rotational movement (two studies: effect size = 70.7%; 95% CI = 58.9-82.5; P < 0.001; I2: 0.0%; P = 0.48). Risk of bias was unclear to low overall, while quality of the evidence ranged from low to moderate. CONCLUSION Allowing for all identified caveats, prediction of rotational tooth movements with aligner treatment does not appear accurate, especially for canines. Careful selection of patients and malocclusions for aligner treatment decisions remain challenging.
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Affiliation(s)
- Despina Koletsi
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Anna Iliadi
- Department of Dental Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Attica, Greece
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
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Authors' response. Am J Orthod Dentofacial Orthop 2021; 159:707. [PMID: 34059208 DOI: 10.1016/j.ajodo.2021.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 03/11/2021] [Indexed: 11/22/2022]
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Chan E, Panayi N, Polychronis G, Papageorgiou SN, Zinelis S, Eliades G, Eliades T. In-house 3D-printed aligners: effect of in vivo ageing on mechanical properties. Eur J Orthod 2021; 44:51-55. [PMID: 33950232 DOI: 10.1093/ejo/cjab022] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To investigate alterations in the mechanical properties of in-house three-dimensional (3D) printed orthodontic aligners after intraoral ageing. MATERIALS AND METHODS Sixteen 3D-printed aligners (TC-85DAC resin, Graphy, Seoul, Korea) were used for the purpose of the study, which were divided into 10 control (not used) aligners and 6 materials retrieved from 4 patients after 1-week service (retrieved group). Samples from the control group were analysed by attenuated total reflectance-Fourier-transform infrared (ATR-FTIR) spectroscopy. Samples from control/retrieved groups were embedded resin and subjected to instrumented indentation testing (IIT) to record force-indentation depth curves, calculating the following (as per ISO 14577-1, 2002 standard): Martens hardness (HM), indentation modulus (EIT), and elastic index (ηIT), and the indentation relaxation index (RIT). Differences between control and retrieved 3D-printed aligners were checked with Mann-Whitney/t-tests at an alpha = 5%. RESULTS ATR-FTIR analysis showed that aligners were made of a vinyl ester-urethane material. The results of the IIT testing were: HM (control: median 91.5 N/mm2, interquartile range [IQR] 88.0-93.0/as-retrieved: median 90.5 N/mm2, IQR 89.0-93.0); EIT (control, mean 2616.3 MPa, standard deviation [SD] 107.0 MPa/retrieved, mean 2673.2 MPa, SD 149.4 MPa); ηIT (control: median 28.6%, IQR 28.2-30.9%/as-retrieved: median 29.0%, IQR 28.7-29.2%); and RIT (control: median 45.5%, IQR 43.0-47.0%/as-retrieved: median 45.1%, IQR 45.0-45.3%). No differences between as-retrieved and control aligners were found for any of the mechanical properties tested (P > 0.05 in all instances). CONCLUSION The mechanical properties of the in-house 3D-printed aligners tested were not affected after 1 week in service period.
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Affiliation(s)
- Esad Chan
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | | | - Georgios Polychronis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Spyridon N Papageorgiou
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - George Eliades
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
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