Impact of various cleaning protocols on the physical and aesthetic properties of 3D-printed orthodontic aligners

Abstract The surface similarity phenomenon describes how users apply maintenance habits from one material to another based on perceived similarities. Cleaning protocols for thermoformed aligners are often used for three-dimensional (3D) printed aligners, despite their different material properties....

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Main Authors: Luka Šimunović, Paula Pečanić, Antun Jakob Marić, Tatjana Haramina, Iva Šrut Rakić, Senka Meštrović
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-04096-z
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author Luka Šimunović
Paula Pečanić
Antun Jakob Marić
Tatjana Haramina
Iva Šrut Rakić
Senka Meštrović
author_facet Luka Šimunović
Paula Pečanić
Antun Jakob Marić
Tatjana Haramina
Iva Šrut Rakić
Senka Meštrović
author_sort Luka Šimunović
collection DOAJ
description Abstract The surface similarity phenomenon describes how users apply maintenance habits from one material to another based on perceived similarities. Cleaning protocols for thermoformed aligners are often used for three-dimensional (3D) printed aligners, despite their different material properties. This study aimed to evaluate how such practices impact the physical and aesthetic properties of 3D-printed aligners. A total of 84 polyurethane-based specimens were fabricated using direct light processing. They were divided into three groups: brushing only, brushing with toothpaste, and immersion in an alkaline solution (Corega). Each protocol simulated two weeks of daily cleaning. Surface roughness was assessed via profilometry and AFM, hardness via the Ball Indentation Method, and color change via VITA Easyshade before and after cleaning. Water absorption was measured daily over 14 days during immersion in either Corega or saline. Statistical analyses included Wilcoxon signed-rank tests, paired t-tests, one-way ANOVA with LSD post-hoc tests, and Kruskal-Wallis tests with post-hoc Dunn test. Brushing with toothpaste caused the greatest increase in surface roughness (ΔSa = 37.45 nm), followed by brushing alone (ΔSa = 10.55 nm); Corega slightly reduced roughness (ΔSa = -4.86 nm). Surface hardness increased after brushing but decreased with Corega (p < 0.05). No significant ΔE color differences were found, though “b” values decreased with brushing (p = 0.012). Water absorption stabilized at 8.47% in saline, while Corega immersion led to peak absorption on day 8 before degradation (p < 0.001). Cleaning methods designed for thermoformed aligners can alter surface properties and degrade 3D-printed aligners. Tailored cleaning protocols are essential to preserve their integrity and functionality.
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spelling doaj-art-7c7bb3efe6d5481d874ba60704ed9c962025-08-20T02:00:08ZengNature PortfolioScientific Reports2045-23222025-05-0115111310.1038/s41598-025-04096-zImpact of various cleaning protocols on the physical and aesthetic properties of 3D-printed orthodontic alignersLuka Šimunović0Paula Pečanić1Antun Jakob Marić2Tatjana Haramina3Iva Šrut Rakić4Senka Meštrović5Department of Orthodontics, School of Dental Medicine, University of ZagrebDepartment of Physics, Faculty of Science, University of ZagrebFaculty of Mechanical Engineering and Naval Architecture, University of ZagrebDepartment of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of ZagrebInstitute of Physics, Centre for Advanced Laser TechniquesDepartment of Orthodontics, School of Dental Medicine, University of ZagrebAbstract The surface similarity phenomenon describes how users apply maintenance habits from one material to another based on perceived similarities. Cleaning protocols for thermoformed aligners are often used for three-dimensional (3D) printed aligners, despite their different material properties. This study aimed to evaluate how such practices impact the physical and aesthetic properties of 3D-printed aligners. A total of 84 polyurethane-based specimens were fabricated using direct light processing. They were divided into three groups: brushing only, brushing with toothpaste, and immersion in an alkaline solution (Corega). Each protocol simulated two weeks of daily cleaning. Surface roughness was assessed via profilometry and AFM, hardness via the Ball Indentation Method, and color change via VITA Easyshade before and after cleaning. Water absorption was measured daily over 14 days during immersion in either Corega or saline. Statistical analyses included Wilcoxon signed-rank tests, paired t-tests, one-way ANOVA with LSD post-hoc tests, and Kruskal-Wallis tests with post-hoc Dunn test. Brushing with toothpaste caused the greatest increase in surface roughness (ΔSa = 37.45 nm), followed by brushing alone (ΔSa = 10.55 nm); Corega slightly reduced roughness (ΔSa = -4.86 nm). Surface hardness increased after brushing but decreased with Corega (p < 0.05). No significant ΔE color differences were found, though “b” values decreased with brushing (p = 0.012). Water absorption stabilized at 8.47% in saline, while Corega immersion led to peak absorption on day 8 before degradation (p < 0.001). Cleaning methods designed for thermoformed aligners can alter surface properties and degrade 3D-printed aligners. Tailored cleaning protocols are essential to preserve their integrity and functionality.https://doi.org/10.1038/s41598-025-04096-zClear aligner applianceCleaning methods3D printing
spellingShingle Luka Šimunović
Paula Pečanić
Antun Jakob Marić
Tatjana Haramina
Iva Šrut Rakić
Senka Meštrović
Impact of various cleaning protocols on the physical and aesthetic properties of 3D-printed orthodontic aligners
Scientific Reports
Clear aligner appliance
Cleaning methods
3D printing
title Impact of various cleaning protocols on the physical and aesthetic properties of 3D-printed orthodontic aligners
title_full Impact of various cleaning protocols on the physical and aesthetic properties of 3D-printed orthodontic aligners
title_fullStr Impact of various cleaning protocols on the physical and aesthetic properties of 3D-printed orthodontic aligners
title_full_unstemmed Impact of various cleaning protocols on the physical and aesthetic properties of 3D-printed orthodontic aligners
title_short Impact of various cleaning protocols on the physical and aesthetic properties of 3D-printed orthodontic aligners
title_sort impact of various cleaning protocols on the physical and aesthetic properties of 3d printed orthodontic aligners
topic Clear aligner appliance
Cleaning methods
3D printing
url https://doi.org/10.1038/s41598-025-04096-z
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