Isfahan University of Medical SciencesDental Research Journal1735-33274120080120Composite-Dentin Bond Strength of Two Adhesives in Different Conditions4747P.Samimi. drj@dnt.mui.ac.irA.FilsoufiK.Fathpour20101106Introduction 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 re-stored with FiltekZ250 (light-cured composite) (3M-RSPE) and Concise (chemically cured compos-ite) (3M-ESPE) composites. Specimens were stored in 37°c distilled water for 24 hours. 10 speci-mens of each group were thermo-cycled 500 times between 5°c to 55°c. Micro- shear 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