Fabrication method to maintain mouthguard thickness regardless of the model angle.

Abstract

The safety and effectiveness of mouthguards depend on the sheet material and thickness. The aim of this study was to investigate the fabrication method for a mouthguard with appropriate thickness using a single sheet regardless of the model angle. Mouthguards were thermoformed using 4.0mm thick ethylene vinyl acetate sheets and a vacuum forming machine. The working models were three hard plaster models trimmed so that the angle of the anterior teeth to the model base was 90°, 100°, and 110°. The model position was 40mm from the front of the forming unit. The sheet was softened until it sagged 15mm, after which the sheet frame was lowered to cover the model. Next, the vacuum was turned on and held for 30seconds for the control. Under the forming conditions in which the model position (MP) was moved, after the model was covered with the sheet, a scissors handle was positioned at the rear of the model and used to push it forward 20mm, and then, the vacuum switch was turned on for 30seconds. Six specimens were formed for each condition. Mouthguard thickness after formation was measured using a specialized caliper. The differences in mouthguard thickness due to forming conditions and model angle were analyzed. The MP was significantly thicker than the control in each model (P<.01). The mouthguard thickness tended to decrease as the model angle increased. The average thickness of the labial surface in the MP was 3mm or more and was not affected by the model angle. This study suggested that the fabrication method in which moving the model forward by 20mm just before formation could produce a mouthguard with approximately 3mm thickness on the labial side with a single sheet regardless of the model angle.