Thinning factors influence on custom‐made mouthguards thermoforming

Abstract

The aim of the present study was to clarify and quantify factors on thinning during a thermoforming using a special simulation model that has three different flat surfaces of 0 degree, 45 degree, and 90 degree against a pressurizing force. Air pressure type samples were made by EVA and acrylic resin blank. Vacuum type samples were also made by EVA. Thickness Gauge was employed to measure the thickness. As results, pressure forming showed significantly larger thinning at 45 and 90 degree surfaces and smaller thinning at 0degree surface, 36 % in thinning rate by vacuum forming and 66% by the pressure forming at 90 degree surface, and 17 and 20 % at 45 degree surface, and 11 and 2% at 0 degree surfaces. Thinning rate of each surface at each heating time was significantly increased with an inclination against the pressure become steep. Promoted thinning by an increase in heating time on 0 degree surface, however, the reverse results of the thinning were restrained with an increase in heating time on 45 and 90 degree surface significantly were obtained. Thinning was increased with the increase in distance from the center in 0 degree surface and increased with the decrease in height in the vertical surface significantly. The air pressure, the material thickness in EVA (Drufosoft), difference in material color did not affect thinning rate. An acrylic resin material showed approximately 10% smaller thinning than EVA (Drufosoft).To retain enough thickness of 3 mm on 90 degree surface corresponding an incisal labial aspects for pressure laminate type, over 55 % reduction is taken into consideration, at least two 3-mm thickness materials should be laminated. On 0 degree surface showed at most 2 % reduction, occlusal thickness becomes almost 6 mm, careful occlusal adjustment to achieve 2 mm thickness should be requested.

Thermoforming method to effectively maintain mouthguard thickness: Effect of moving the model position just before vacuum formation

“…The development of devices with various characteristics is progressing such as a semi‐automatic type and a device capable of indentations of the occlusal surface . Therefore, many researchers and clinicians use forming devices for mouthguard fabrication . However, thickness reduction of fabricated mouthguards can range from 35% to 60% .…”

Thermoforming technique for maintaining the thickness of single‐layer mouthguard during pressure formation

“…However, because the thickness of mouthguards is reduced by 35%‐60% during fabrication, the conventional thermoforming method cannot produce sufficiently thick mouthguards with a single layer. Laminated mouthguards are superior in that they can arbitrarily be adjusted to a portion where the thickness is to be secured, such as the anterior portion and occlusal surface, without being influenced by the occlusal state and the dentition morphology; thus, laminated mouthguards are recommended . However, it is difficult to convince all players to use the laminated‐type mouthguard for reasons such as cost or time spent to construct the mouthguard .…”

Effect of the anteroposterior position of the model on fabricated mouthguard thickness: Part 2 Influence of sheet thickness and material

“…The sheet then stretches toward the model during molding. Factors that affect shape change during the second stage are sheet thickness, color, material, production method, and the model shape …”