Evaluation of effect of adding silica fillers to adhesive on microleakage of composite restorations in different times

Abstract Background and Aim: Dental adhesives are widely used in modern dentistry to pro-vide retention of composite resin restoration and to reduce associated marginal micro-leakage. We aimed to evaluate the effect of adding silica fillers to adhesive on micro-leakage of composite restorations in different times. Materials and Methods: Forty-eight premolars were collected in 0.5% chloramine T solution. The teeth were divided into two groups. CLV cavities were prepared. In the first group, SE bond and in the second group, experimental unfilled SE bond were applied. In subgroups 1 of both groups, the teeth were incubated for 3 months then evaluated. In subgroups 2 of both groups, evaluation was performed after 24 hours. Cavities were filled with Z250 composite resin. Before incubation, samples were thermocycled at 5 to 55° C in 1000 cycles, then immersed in silver nitrate solution and afterwards developer solution for microleakage evaluation. They were then mounted, sectioned and observed under steriomicroscope and scanning electron microscope for scoring. The data were analyzed with Kruskal-Wallis and Mann-Whitney tests. Results: There was significant difference in microleakage between groups in different times. There was no significant difference between occlusal microleakage regardless of time (p < 0.001). The difference between cervical microleakage of two adhesive types was not significant (p=0.533). There was significant difference between 24 hours and 3 months storage (p < 0.001). No significant difference was detected between filled and unfilled adhesives regardless of time (p < 0.001). Conclusion: Although there was no significant difference between the two adhesives, unfilled adhesives performed slightly better than filled adhesives. Key Words: Microleakage – Filled adhesive – Composite filling