Comparative Evaluation of Surface Roughness Using Two Different Mechanical Surface Treatments and their Effect on Microshear Bond Strength Using Different Nanocomposites: An In vitro Sem Study

Abstract

Introduction: This study compared the impact of surface roughness on the microshear bond strength of nanocomposites to dentin that underwent airborne abrasion and conventional rotary tools as two distinct mechanical surface treatments. The study also sought to determine how well the Self Etch Adhesive method worked in creating a strong bond following dentinal air abrasion. Materials and Methodology: Fourty six extracted human molars were used for this in-vitro study. The occlusal third of the crown was sectioned to the expose the dentin and the specimen were randomly assigned into two main groups based on the mechanical surface treatment. Each group was further subdivided into two subgroups based on the nature of composite resin used. Group 1A : abrasion with diamond bur followed by restoration with nanohybrid resin. Group 1B: abrasion with diamond bur followed by restoration with nanofilled resin. Group 2A: air-borne dentin abrasion followed by restoration with nanohybrid resin. Group 2B: air-borne dentin abrasion followed by restoration with nanofilled resin. Results: Results showed that Group 1A demonstrated significantly higher mean Microshear bond strength as compared to Group 2A & Group 2B at P<0.001. This was followed next by Group 1B  showing significantly higher mean Microshear bond strength as compared to Group 2A & Group 2B at P <0.001.These results  infer that air abrasion with aluminum oxide particles decreased the bond strength for the self adhesive system tested, irrespective of the type of nanocomposite used when tested under UTM. The study also concluded that the Nanohybrid composites performed better in terms of bond strengths in comparison with the Nanofilled composites regardless of the surface treatment.