Aim: this study was subjected to investigate the effect of different caries removal methods on immediate and delayed microtensile bond strength of universal adhesives to artificial caries affected dentin.
Materials and methods: 60 anonymous extracted human molar teeth were used in this study. The teeth were mounted into acrylic blocks then the coronal enamel and dentin was removed exposing a flat surface of dentin. Then all the specimens were submitted to a pH-cycling model to simulate artificial caries-affected dentin. Two universal adhesives were used GPDM and 10-MDP containing universal adhesive. Teeth were divided into three groups (n=20) according to the type of caries removal method gp 1: diamond bur, gp 2: smart bur, gp 3: laser. Then each group was further subdivided into two subgroups (n=10) according to the type of universal adhesive used. Half of the specimens from each group were tested for Microtensile bond strength (μTBS) immediately and the other half were tested for (μTBS) after 6 months of storage.
Results: The diamond bur recorded significantly higher values of μTBS than other methods, while smart prep bur recorded the lowest bond strength. 10-MDP containing universal adhesive showed significantly immediate stronger microtensile bond strength but showed non -significant higher bond deterioration in delayed μTBS than GPDM containing universal adhesive
Conclusion: The bond strength changes under various circumstances and at different times between different types of dentin bonding systems and different caries removal methods