In Vitro Microleakage Evaluation of Total- etch and Self- etch Bonding Systems

Statement of Problem: Bonded restorations have a number of advantages over traditional, non-adhesive methods. Adhesion reduces the microleakage at the restoration- tooth interface. Prevention of microleakage, or the ingress of oral fluids and bacteria along the cavity wall, reduces the clinical problems such as postoperative sensitivity, marginal staining, and recurrent caries, all of which may jeopardize the clinical longevity of restorative efforts. The aim of this study was to evaluate the microleakage in class V composite restoration with total-etch and self-etch adhesive systems. In this in- vitro study, 48 standard class V cavities were prepared in the buccal surface of human extracted premolars so that the occlusal margins of the cavities were in the enamel and the gingival margins in the dentin (cementum). The teeth were divided into two groups of 24. In the first group, the cavities were restored with total- etch system (Excite) and composite. The teeth in the second group were restored with self-etch system (Prompt L- Pop) and the same composite. The teeth were thermocycled 500 times between 5 - 55°c and then were covered with nail- polish and adhesive wax except for 1 mm around cavities, and all teeth were immersed into the 2% methylene blue for 10 hours. The samples were mounted in polyester blocks, sectioned longitudinally at the middle of the cavities, and evaluated for microleakage under a stereomicroscope at 40x magnification. Dye penetration was scored between 0-3. Data were analyzed with Mann Whitney and Wilcoxon tests. In the enamel and dentin margins, microleakage for the total-etch group was found to be less than the self-etch group (p <0.05). A significant difference in the microleakage mean rank of the enamel and dentin margins was observed (p < 0.05). Microleakage in the enamel margins was less than that in the dentin margins. Total-etch adhesive system showed a significant difference on the microleakage of class V composite restorations especially in the enamel margin.