In vitro evaluation of the effect of deproteinization on the marginal leakage of resin restorations using three bonding agents

The perfect sealing of the tooth/restoration interface is important to prevent bacteria penetration that may lead to secondary caries and also, when dentin is involved, prevent excessive fluid movement in the dentinal tubules that may cause hypersensitivity. The aim of this study was to evaluate the effect of deproteinization and application of reducing agent on the marginal integrity of composite restorations using three different bonding agents (Prime & Bond NT, AdheSE and G-Bond). Class V cavities were prepared on the buccal surface of 90 recently extracted human premolars and were divided into three groups (I, II, and III) based on the adhesives. Each group was subdivided into three subgroups of 10 each according to the surface treatment: application according to clinical protocol; etching with 37% phosphoric acid for 15 seconds/5% NaOCl; 10% sodium ascorbate after etching/NaOCl. The cavities were restored with Filtek Z 350 nanocomposite. The specimens were sectioned and evaluated under stereomicroscope. The morphology of the resin-dentin interface was visualized using SEM. Statistical analysis was done using Kruskal-Wallis one-way ANOVA followed by a Mann-Whitney U- test (P<0.05). Group I showed significantly least microleakage among the groups. No significant difference in microleakage was found between groups I and II. Within the subgroups for each group, no significant difference in microleakage scores was observed. SEM micrographs presented gap free areas in group I and varying degrees of gaps in the other two groups. Etch and rinse adhesives were tenable for deproteinization than self etch adhesives.