An in vitro comparison of adhesive techniques and rotary instrumentation on shear bond strength of nanocomposite with simulated pulpal pressure.

Aim: The aim of this study is to evaluate the shear bond strength of composite to tooth using different adhesive techniques and rotary instruments under simulated pulpal pressure. Materials and Methods: Sixty extracted human molars were randomly divided into two groups of 30 samples each (group I and II), according to the adhesive technique followed (i.e. total etch and self etch groups). Each group was further divided into two sub-groups (Sub-groups A and B) of 15 samples each according to the cutting instrument (diamond abrasive or carbide burs) used. Class II cavities were made with diamond abrasive or carbide burs, and restored with nano-composite under positive intra-pulpal pressure. Shear bond strength of the specimens were recorded simultaneously. Results: After statistical evaluation using two-way ANOVA and t-test, the mean shear bond strength values of the groups are as follows: Group IA- 4.69 MPa, Group IB-6.15 MPa, Group IIA-4.3 MPa, and Group IIB-6.24 MPa. It was seen that group IIB showed highest bond strength followed by group IB. Group II A showed the least bond strength. Conclusions: Within the limitations of the study, diamond abrasive gave better bond strength than carbide bur with both the adhesive techniques.