Revista de Odontologia da UNESP
https://revodontolunesp.com.br/article/doi/10.1590/1807-2577.20250010
Revista de Odontologia da UNESP
Original Article

Evaluation of color stability of orthodontic aligners: in vitro study

Avaliação da estabilidade da cor de alinhadores transparentes: estudo in vitro

Roberto Hideo SHIMIZU; Maria Fernanda Castoldi DIAVÃO; Mariana DALLEDONE; Gil Guilherme GASPARELLO; Beatriz Almeida SHIMIZU; Evelise Machado de SOUZA; Ana Cláudia Moreira Melo TOYOFUKU

http://dx.doi.org/10.1590/1807-2577.20250010 Rev. odontol. UNESP, vol.54, e20250010, 2025
PDF
Downloads: 0
Views: 176

Abstract

Introduction: The esthetics of orthodontic aligners is directly related to the optical stability of the thermoplastic materials used in their fabrication.

Objective: This study aimed to evaluate the transparency stability of thermoplastic materials used in the fabrication of orthodontic aligners after exposure to staining solutions.

Material and method: A total of 160 specimens were prepared and divided into two groups based on the material: ClearQuartz (QTZ) and SmartTrack (INV), with 80 specimens each. Each group was further subdivided into five subgroups (n = 16) according to the immersion solution: coffee, tea, Coca-Cola, red wine, and artificial saliva (control). Transparency measurements were performed using a VITA EasyShade Compact spectrophotometer, focusing on the buccal surface of the lower first and second molars. The specimens were immersed in the solutions for 14 days, with daily replacement of the liquids. Assessments were conducted at four times: baseline (T0), 24 hours (T1), 7 days (T2), and 14 days (T3), under controlled environmental conditions.

Result: Tea, red wine, and coffee solutions produced statistically significant differences in transparency between QTZ and INV at all evaluation time points. In the Coca-Cola group, no significant difference was observed between the materials at T1–T0, but differences emerged at later intervals. For the artificial saliva control, a significant difference was found only at T3–T0, with no significant variation at earlier time points.

Conclusion: SmartTrack specimens demonstrated lower transparency stability compared to ClearQuartz, particularly after exposure to staining agents such as tea, coffee, Coca-Cola, and red wine, across most time intervals evaluated.

Keywords

Aesthetic aligners; pigmentation; orthodontics; colorimetry; clear aligners

Resumo

Introdução: A estética dos alinhadores ortodônticos está diretamente relacionada à estabilidade óptica dos materiais termoplásticos utilizados na confecção desses dispositivos.

Objetivo: Este estudo teve como objetivo avaliar a estabilidade da transparência de materiais termoplásticos utilizados na confecção de alinhadores ortodônticos após a exposição a soluções pigmentantes.

Material e método: Foram preparados 160 corpos de prova, divididos em dois grupos conforme o material: ClearQuartz (QTZ) e SmartTrack (INV), com 80 amostras em cada grupo. Cada grupo foi subdividido em cinco subgrupos (n = 16) de acordo com a solução de imersão: café, chá, Coca-Cola, vinho tinto e saliva artificial (controle). As medições de transparência foram realizadas com o espectrofotômetro VITA EasyShade Compact, com foco na superfície vestibular dos primeiros e segundos molares inferiores. Os corpos de prova foram imersos nas soluções por 14 dias, com substituição diária dos líquidos. As avaliações foram realizadas em quatro momentos: inicial (T0), 24 horas (T1), 7 dias (T2) e 14 dias (T3), em ambiente controlado.

Resultado: As soluções de chá, vinho tinto e café produziram diferenças estatisticamente significativas na transparência entre os grupos QTZ e INV em todos os momentos avaliados. No grupo Coca-Cola, não houve diferença significativa entre os materiais no intervalo T1–T0, mas diferenças foram observadas nos tempos subsequentes. Para a saliva artificial, foi identificada diferença estatisticamente significativa apenas no intervalo T3–T0, sem variação significativa nos momentos anteriores.

Conclusão: As amostras do grupo SmartTrack apresentaram menor estabilidade de transparência em comparação ao grupo ClearQuartz, especialmente após exposição a agentes pigmentantes como chá, café, Coca-Cola e vinho tinto, na maioria dos períodos avaliados.

Palavras-chave

Alinhadores estéticos; pigmentação; ortodontia; colorimetria; alinhadores transparentes

References

1 Cooper-Kazaz R, Ivgi I, Canetti L, Bachar E, Tsur B, Chaushu S, et al. The impact of personality on adult patients’ adjustability to orthodontic appliances. Angle Orthod. 2013 Jan;83(1):76-82. http://doi.org/10.2319/010312-6.1. PMid:22594776.

2 Weir T. Clear aligners in orthodontic treatment. Aust Dent J. 2017 Mar;62(S1 Suppl 1):58-62. http://doi.org/10.1111/adj.12480. PMid:28297094.

3 Rosvall MD, Fields HW, Ziuchkovski J, Rosenstiel SF, Johnston WM. Attractiveness, acceptability, and value of orthodontic appliances. Am J Orthod Dentofacial Orthop. 2009 Mar;135(3):276.e1-12. http://doi.org/10.1016/j.ajodo.2008.07.011. PMid:19268820.

4 Buschang PH, Shaw SG, Ross M, Crosby D, Campbell PM. Comparative time efficiency of aligner therapy and conventional edgewise braces. Angle Orthod. 2014 May;84(3):391-6. http://doi.org/10.2319/062113-466. PMid:24749702.

5 Zheng M, Liu R, Ni Z, Yu Z. Efficiency, effectiveness and treatment stability of clear aligners: a systematic review and meta-analysis. Orthod Craniofac Res. 2017 Aug;20(3):127-33. http://doi.org/10.1111/ocr.12177. PMid:28547915.

6 Bernard G, Rompré P, Tavares JR, Montpetit A. Colorimetric and spectrophotometric measurements of orthodontic thermoplastic aligners exposed to various staining sources and cleaning methods. Head Face Med. 2020 Feb;16(1):2. http://doi.org/10.1186/s13005-020-00218-2. PMid:32070379.

7 Ercoli F, Tepedino M, Parziale V, Luzi C. A comparative study of two different clear aligner systems. Prog Orthod. 2014 May;15(1):31. http://doi.org/10.1186/s40510-014-0031-3. PMid:24934094.

8 Hahn W, Engelke B, Jung K, Dathe H, Fialka-Fricke J, Kubein-Meesenburg D, et al. Initial forces and moments delivered by removable thermoplastic appliances during rotation of an upper central incisor. Angle Orthod. 2010 Mar;80(2):239-46. http://doi.org/10.2319/033009-181.1. PMid:19905847.

9 Liu CL, Sun WT, Liao W, Lu WX, Li QW, Jeong Y, et al. Colour stabilities of three types of orthodontic clear aligners exposed to staining agents. Int J Oral Sci. 2016 Dec;8(4):246-53. http://doi.org/10.1038/ijos.2016.25. PMid:27660048.

10 Šimunović L, Agović SC, Marić AJ, Bačić I, Klarić E, Uribe F, et al. Color and chemical stability of 3D-printed and thermoformed polyurethane-based aligners. Polymers. 2024;16(8):1067. http://doi.org/10.3390/polym16081067. PMid:38674987.

11 Wible E, Agarwal M, Altun S, Ramir T, Viana G, Evans C, et al. Long-term effects of various cleaning methods on polypropylene/ethylene copolymer retainer material. Angle Orthod. 2019 May;89(3):432-7. http://doi.org/10.2319/060818-429.1. PMid:30605015.

12 Charavet C, Gourdain Z, Graveline L, Lupi L. Cleaning and disinfection protocols for clear orthodontic aligners: a systematic review. Healthcare. 2022 Feb;10(2):340. http://doi.org/10.3390/healthcare10020340. PMid:35206954.

13 Lombardo L, Arreghini A, Maccarrone R, Bianchi A, Scalia S, Siciliani G. Optical properties of orthodontic aligners--spectrophotometry analysis of three types before and after aging. Prog Orthod. 2015;16(1):41. http://doi.org/10.1186/s40510-015-0111-z. PMid:26582007.

14 Zafeiriadis AA, Karamouzos A, Athanasiou AE, Eliades T, Palaghias G. In vitro spectrophotometric evaluation of Vivera clear thermoplastic retainer discolouration. Aust Orthod J. 2014 Nov;30(2):192-200. http://doi.org/10.2478/aoj-2014-0017. PMid:25549522.

15 R Development Core Team. R: a language and environment for statistical computing. Version 4.1.3. Vienna: R Foundation for Statistical Computing; 2022.

16 Daniele V, Macera L, Taglieri G, Spera L, Marzo G, Quinzi V. Color Stability, chemico-physical and optical features of the most common PETG and PU based orthodontic aligners for clear aligner therapy. Polymers. 2021 Dec;14(1):14. http://doi.org/10.3390/polym14010014. PMid:35012036.

17 Miller KB, McGorray SP, Womack R, Quintero JC, Perelmuter M, Gibson J, et al. A comparison of treatment impacts between Invisalign aligner and fixed appliance therapy during the first week of treatment. Am J Orthod Dentofacial Orthop. 2007 Mar;131(3):302.e1-9. http://doi.org/10.1016/j.ajodo.2006.05.031. PMid:17346581.

18 Karkhanechi M, Chow D, Sipkin J, Sherman D, Boylan RJ, Norman RG, et al. Periodontal status of adult patients treated with fixed buccal appliances and removable aligners over one year of active orthodontic therapy. Angle Orthod. 2013 Jan;83(1):146-51. http://doi.org/10.2319/031212-217.1. PMid:22725616.
 

Submitted date:
05/06/2025

Accepted date:
09/22/2025

6915ff73a95395627a12462c rou Articles
Links & Downloads
1807-2577 (Electronic)
Rev. odontol. UNESP ©2025 All rights reserved.

Rev. odontol. UNESP

Share this page
Page Sections