Appropriate fabrication method for vacuum-formed mouthguards using polyolefin sheets

Background/Aims The appropriate heating conditions for polyolefin sheets have not yet been determined and polyolefin sheets are usually formed in the same manner as ethylene vinyl acetate sheets. The aim of this study was to examine the appropriate heating conditions for polyolefin sheets when fabricating vacuum-formed mouthguards. Materials and methods Mouthguard sheets of 3.0 mm polyolefin were vacuum formed on working models at three heating temperatures: 90 degrees C, 105 degrees C, and 120 degrees C. The thickness of the mouthguard was measured at the labial surface of the central incisor, and the buccal and occlusal surfaces of the first molar. The fit of the mouthguard was examined at the central incisor and the first molar by measuring the distance between the mouthguard and the cervical margin of the working model. Differences in the thickness and fit of the mouthguards according to the heating conditions and the measured regions were analyzed by two-way analysis of variance. Results Mouthguard thickness varied among the measured regions of the central incisors and first molars (P < .01). The smallest thickness was found at the labial surface of the central incisor in mouthguards fabricated at 90 degrees C (P < .01). The smallest thickness was found at the buccal and occlusal surface of the first molar in mouthguards fabricated at 120 degrees C (P < .01). The worst fit was obtained with the heating temperature of 90 degrees C (P < .01). Conclusions The appropriate heating temperature for polyolefin sheets was 105 degrees C to maintain mouthguard thickness and to obtain proper fit.