Assessing change in mouthguard thickness according to the thickness of the original mouthguard sheet

The aim of this study was to examine changes in thickness and differences in rate of change of mouthguard thickness according to the thickness of the original sheet used to form the mouthguard. The material used in this study was Sports Mouthguard (3.0, 3.8, and 5.0 mm thicknesses, ethylene vinyl acetate sheet). The sheets were heated until they hung 15 mm from the baseline and were then vacuum formed. The thickness of the mouthguard was measured, and the rate of change of thickness was calculated. The differences in thickness and rate of change of thickness at the labial surface of the central incisor and buccal surface of the first molar according to the thickness of sheet were analyzed by one-way anova, and that of the occlusal surface of the first molar was analyzed by the Kruskal-Wallis test. The results showed that the thickness of mouthguard increased as the thickness of sheet increased (P < 0.05 or P < 0.01). The thickness of the sheet did not affect the rate of change of thickness at the central incisor and occlusal surface of the first molar. Adequate thickness could be obtained using the original sheet with a thickness >3.8 mm at the buccal surface of the first molar and >3.0 mm at the occlusal surface of the first molar. At the central incisor, the necessary thickness of the original sheet was calculated as 5.6 mm. These results would be useful for selecting the appropriate mouthguard sheet material.