Composite-Dentin Bond Strength of Two Adhesives in Different Conditions

Introduction: The purpose of this study was to evaluate the effect of thermo-cycling and curing mode of composites (light and chemical curing) on dentin bond strength of one all-in-one and an one-bottle bonding systems. Methods and Materials: Occlusal enamels of eighty caries-free third molars were ground with a model trimmer to create flat surfaces in superficial dentin for bonding, and randomly divided into 4 groups. Teflon molds with 1 mm internal diameter were mounted on the flat surfaces, Prompt L-pop (all-in-one system) (3M-ESPE) and Single-Bond (one-bottle system) (3M-ESPE) were used and restored with FiltekZ250 (light-cured composite) (3M-RSPE) and Concise (chemically cured composite) (3M-ESPE) composites. Specimens were stored in 37°c distilled water for 24 hours. 10 specimens of each group were thermo-cycled 500 times between 5°c to 55°c. Microshear bond strength test was done with 0.5mm/min crosshead speed (Dartec, England). The data were analyzed by ANOVA and Duncan's tests. Results: The mean shear bond strengths of two adhesive systems with light-cured composite showed no significant differences with and without thermo-cycling (P<0.05). Also, there was no significant difference between bond strength of two adhesive systems with light-cured composite (P<0.05). Use of chemically cured composite reduced the bond strength of Single-Bond significantly (P<0.001). There was not any bond between chemically cured composite to dentin, using