Page 124 - MSAM-4-2

Materials Science in

Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Disinfection efficiency and its impact on

the mechanical properties of multi-material
mouthguards fabricated via fused filament

fabrication

Leonor Bispo , Joana F. Henriques , Ana P. Piedade* , and Ana M. Sousa
Department of Mechanical Engineering, CEMMPRE, University of Coimbra, 3030-788 Coimbra,
Portugal

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
*Corresponding author:
Ana Piedade on mechanical properties was also evaluated, comparing physical (ultraviolet [UV]-C
(ana.piedade@dem.uc.pt) light exposure) and chemical (Polident cleaning tablet solution) disinfection strategies.
Citation: Bispo L, Henriques JF, In addition, the effects of artificial saliva aging on all material types and configurations
Piedade AP, Sousa AM. Disinfection were examined. Mechanical testing revealed that multi-material configurations
efficiency and its impact on the containing HIPS exhibited superior mechanical performance, with flexural stiffness
mechanical properties of multi-
material mouthguards fabricated via values 8 – 40% higher than PMMA-based samples, Vickers microhardness 40 – 128%
fused filament fabrication. Mater Sci greater, and absorbed energy and impact strength improved by 11 – 105%. Moreover,
Add Manuf. 2025;4(2):025130018. the tri-layered configuration demonstrated enhanced mechanical behavior, showing
doi: 10.36922/MSAM025130018
approximately 40% higher transverse impact resistance and increases of ~35%
Received: March 28, 2025 and ~77% in flexural strength and modulus, respectively, relative to the bi-layered
Revised: April 13, 2025 configuration. Disinfection studies confirmed the efficacy of both approaches,
reducing Staphylococcus aureus colony-forming units by 95% (Polident) and 97% (UVC
Accepted: April 22, 2025
light). These findings are promising for the development of protective mouthguards,
Published online: May 20, 2025 where changes in mechanical properties over time – particularly due to saliva exposure
Copyright: © 2025 Author(s). and disinfection – are of critical importance.
This is an Open-Access article
distributed under the terms of the
Creative Commons Attribution Keywords: Mouthguards; Multi-material configuration; Disinfection; Material
License, permitting distribution, characterization; Additive manufacturing
and reproduction in any medium,
provided the original work is
properly cited.
Publisher’s Note: AccScience
Publishing remains neutral with 1. Introduction
regard to jurisdictional claims in
published maps and institutional Orofacial injuries are common in contact sports, where athletes are frequently exposed
affiliations. to high-impact forces. Sports such as boxing, rugby, karate, wrestling, and hockey are

Volume 4 Issue 2 (2025) 1 doi: 10.36922/MSAM025130018