Effect of Thermocycling on the Shear Bond Strength of Different Resins Bonded to Thermoplastic Foil Applied in Occlusal Splint Therapy

Purpose Temporomandibular disorders are a group of symptoms related to the impaired function of the temporomandibular joints and associated muscles. Occlusal splint therapy is a common treatment in the aforementioned syndrome. One of the methods of manufacturing occlusal splints is to place a polymer on thermoplastic foil. The aim of this study was to evaluate the shear bond strength of light- and self-cured resins bonded to thermoplastic foil dependent on artificial aging. Materials and Methods Thirty cylinders composed of light-cured resin and 30 cylinders made of self-cured resin were attached to 60 rectangular thermoplastic plates. All specimens were divided into six groups. A control study was conducted for groups 1 and 2. The other preparation groups were subjected to thermocycling by setting appropriately 1000 cycles for groups 3 and 4 and 3000 cycles for groups 5 and 6 in distilled water. Bond strength was measured in a universal testing machine. The results were subjected to statistical analysis using the Mann-Whitney U test (p ≤ 0.05). Results The statistics revealed that the values of the shear bond strength for specimens composed of self-cured resin after 1000 and 3000 thermocycles were significantly higher than on those made of light-cured resin (p = 0.003 and p = 0.002). Conclusion The shear bond strength between the self-cured resin and the thermoplastic foil was higher and more resistant to aging than the shear bond strength between the light-cured resin and the thermoplastic foil.