Shear bond strength of adhesive systems to enamel and dentin. Thermocycling influence

Objectives: The purpose of the this study was to evaluate the influence of thermocycling on shear bond strength on bovine enamel and dentin surfaces of different adhesive systems. Methods: Thirty sound bovine incisors were sectioned in mesiodistal and inciso-cervical direction obtaining 60 incisal surfaces (enamel) and 60 cervical surfaces (dentin). Specimens were randomly assigned to 3 groups of equal size (n = 40), according to the adhesive system used: I—Single Bond; II—Prime & Bond NT/NRC; III—One Coat Bond. After 24-h storage in distilled water at 37oC, each main group was divided into two subgroups: A- specimens tested after 24 h storage in distilled water at 37 ∘C; B - specimens submitted to thermocycling (500 cycles). Shear bond strength tests were performed. Data were submitted to ANOVA and Tukey test. Results: Means (MPa) of different groups were: I—AE-16.96, AD-17.46; BE-21.60, BD-12.79; II—AE-17.20, AD-11.93; BE-20.67, BD-13.94; III—AE-25.66, AD-17.53; BE-24.20, BD-19.38. Significance: Thermocycling did not influence significantly the shear bond strength of the tested adhesive systems; enamel was the dental substrate that showed larger adhesive strength; One Coat Bond system showed the best adhesive strength averages regardless of substrate or thermocycling.