Longitudinal Deterioration of Custom‐Made Mouthguard Fit During 12 Months of Use in Athletes: Implications for Traumatic Dental Injury Prevention

OBJECTIVES: To investigate longitudinal changes in fit and user-reported outcomes of custom-made ethylene vinyl acetate (EVA) mouthguards during 12 months of athletic use, and to explore implications for traumatic dental injury prevention. METHODS: This prospective 12-month longitudinal observational study included 41 athletes using custom-made EVA mouthguards during training and competition. Mouthguard fit was evaluated at baseline, 6 months, and 12 months using a validated intraoral silicone weight method. User-reported outcomes were assessed using visual analogue scale questionnaires. Changes over time were analyzed using the Friedman test. RESULTS: Fit-checking material weight increased significantly over time, representing a 48% relative increase at 12 months compared with baseline (p < 0.05), indicating progressive loss of fit. In contrast, most user-reported comfort and function scores showed no significant changes across time points. CONCLUSION: Custom-made EVA mouthguards show progressive fit deterioration over time despite stable user-reported comfort. These findings suggest that subjective perception alone may not accurately reflect changes in mouthguard fit, highlighting the importance of objective fit assessment during routine sports dental care.