The influence of temperature on sheet lamination process when fabricating mouthguard on dental thermoforming machine

Abstract

Laminated custom-made mouthguards tend to delaminate with use; this is a problem in clinical use. Insufficient bonding strength causes delamination, and bonding strength is strongly affected by heating temperature during lamination. The present study aimed to evaluate the influence of heating temperature on the sheet lamination process. Seven mouthguard sheet products were laminated together at different heating temperatures. To evaluate the bonding strength, a delamination test (n = 6) was performed, and the fracture patterns were inspected visually. To evaluate the shock absorption capability, a falling impact test (n = 5) was performed, and the specimen thicknesses were measured. All recorded values were analyzed using two-way analysis of variance and Tukey's Honest Significant Difference Test (P < 0.05). The present study confirmed that bonding strength was dependent on heating temperature: In ethylene-vinyl acetate copolymer products, the bonding strength was almost constant at 130°C and above, and it was constant at 110°C and above in polyolefin products. The thickness of every specimen decreased and, in some specimens, the shock absorption capability decreased with increasing heating temperature. The present study concludes that the heating temperature during the sheet lamination process when laminated custom-made mouthguards are fabricated may not be less than 120°C in ethylene-vinyl acetate copolymer products and 110°C in polyolefin products.

Present Status in Polymeric Mouthguards. A Future Area for Additive Manufacturing?

“…In dentistry, the first reported application of these polymers was for the production of dentures. With the increased knowledge of these materials' properties, they started to be pointed as good alternatives for custom-made mouthguards production [57,92]. Compared with EVA, these polymers show higher tensile and tear strength with similar shock absorption capacity [92].…”

“…The weak interfacial adhesion can explain this fact, which may be related to contamination of the polymeric sheets’ surface and the temperature of the thermoforming process. Higher temperatures usually imply stronger bonds [ 55 , 56 , 57 ].…”

Use of the fiberglass reinforcement method in thermoplastic mouthguard materials to improve flexural properties for enhancement of functionality

“…Their report inferred that the temperature of the adhesive surface was approximately 110°C just before forming. However, some studies showed that higher adhesive strengths could be obtained using solvents and by adjusting the heating conditions 20,35) . This could be attributed to the fact that although the preparation of the specimens was different, their results were comparable.…”

“…The present study was conducted under normal atmospheric pressure in dry conditions without using any resin modifier or any processing agent. The bond strength is considered to be clinically more than 4 N/mm 35) . The bond strength might be improved by examining the surface treatment method of the glass fiber.…”

Fabrication of Shock Absorbing Photopolymer Composite Material for 3D Printing Sports Mouthguard

“…Many different impact tests exist, including the Charpy test, Izod test, tensile test, and drop test. The steel ball drop test was selected in this study because it is a popular method that yields results that correspond closely to the actual impact strength of the examined material [38]. The impact force was generated by a free-falling stainless-steel ball (weight: 32.6 g, diameter: 20 mm) dropped from a 60-cm height onto the test specimen, which was placed on a steel platform that was supported by a load cell sensor system.…”