AccScience Publishing / MSAM / Volume 4 / Issue 2 / DOI: 10.36922/MSAM025130018
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ORIGINAL RESEARCH ARTICLE

Disinfection efficiency and its impact on the mechanical properties of multi-material mouthguards fabricated via fused filament fabrication

Leonor Bispo1 ,  Joana F. Henriques1 ,  Ana P. Piedade1* ,  Ana M. Sousa1
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1 Department of Mechanical Engineering, CEMMPRE, University of Coimbra, 3030-788 Coimbra, Portugal
MSAM 2025, 4(2), 025130018 https://doi.org/10.36922/MSAM025130018
Received: 28 March 2025 | Accepted: 22 April 2025 | Published online: 20 May 2025
© 2025 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
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Abstract

Mouthguards are orthodontic devices designed to prevent orofacial injuries during sports activities. To ensure comfort and correct positioning, they must fit the athlete’s dental arch precisely. Customization through additive manufacturing offers a practical solution for producing well-fitted mouthguards. The present study aimed to investigate the use of 3D-printed multi-material parts in the fabrication of protective mouthguards. Three polymeric materials were employed: High-impact polystyrene (HIPS), thermoplastic polyurethane, and poly(methyl methacrylate) (PMMA). Two configurations – bi-layered and tri-layered – were analyzed to assess the influence of material arrangement on mechanical performance. The impact of disinfection methods on mechanical properties was also evaluated, comparing physical (ultraviolet [UV]-C light exposure) and chemical (Polident cleaning tablet solution) disinfection strategies. In addition, the effects of artificial saliva aging on all material types and configurations were examined. Mechanical testing revealed that multi-material configurations containing HIPS exhibited superior mechanical performance, with flexural stiffness values 8 – 40% higher than PMMA-based samples, Vickers microhardness 40 – 128% greater, and absorbed energy and impact strength improved by 11 – 105%. Moreover, the tri-layered configuration demonstrated enhanced mechanical behavior, showing approximately 40% higher transverse impact resistance and increases of ~35% and ~77% in flexural strength and modulus, respectively, relative to the bi-layered configuration. Disinfection studies confirmed the efficacy of both approaches, reducing Staphylococcus aureus colony-forming units by 95% (Polident) and 97% (UVC light). These findings are promising for the development of protective mouthguards, where changes in mechanical properties over time – particularly due to saliva exposure and disinfection – are of critical importance.

Graphical abstract
Keywords
Mouthguards
Multi-material configuration
Disinfection
Material characterization
Additive manufacturing
Funding
Joana F. Henriques and Ana M. Sousa acknowledge financial support from FCT, Portugal, through the PhD grants 2023.00752.BD and UI/BD/150913/2020, respectively.
Conflict of interest
Ana P. Piedade serves as the Editorial Board Member of the journal but did not in any way involved in the editorial and peer-review process conducted for this paper, directly or indirectly. Other authors declare they have no competing interests.
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Materials Science in Additive Manufacturing, Electronic ISSN: 2810-9635 Published by AccScience Publishing
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