Evaluation of shear bond strength of amalgam restorations repaired with composite resin by different surface treatments

Abstract

Aim: Repairing amalgam restorations with composite resins is a clinical practice with many advantages. An effective adhesion is achieved between amalgam and composite by applied different surface treatment on amalgam surface. In this study, the effect of adhesive systems applied on amalgam surface on composite-amalgam connection was investigated. Methodology: Standard cavities were opened in 70 acrylic molds that had completed their polymerization and amalgams were placed in these cavities. Seven groups were randomly assigned to different surface treatments on amalgam. In group 1 only roughening with diamond bur, in group 2 acid etch, in group 3 acid application after roughening with diamond bur, in group 4 roughening with diamond bur and silane, in group 5 acid etch and silane, in group 6 roughening with diamond bur and Alloy Primer and finally 7. acid etch and Alloy Primer was applied in the samples. After the application of clearfil universal bond to all groups, composite resins were placed and polymerized. Shear bond strengths were tested with a Universal testing machine. Obtained data were evaluated by one way ANOVA and Tukey B tests. Results: In the statistical evaluation of the groups, the highest shear bond strength between amalgam-composite was seen in the 3rd group where both roughening with diamond bur and acid were applied together, and the lowest shear bond strength was seen in the first group with only roughening with diamond bur. The differences between the groups were statistically significant (p<0.05). Conclusions: The roughening of the amalgam surface affects the shear bond strength between amalgam and composite resin. These results obtained in vitro conditions should be supported with clinical studies.