Marginal Leakage in Interfaces Formed by Bovine Dentin and Adhesive Cements Applied with Different Bonding Techniques

Objectives: The aim of this in vitro study was to evaluate the marginal microleakage in interfaces formed by bovine dentin and adhesive cements applied with different bonding techniques. Materials and Methods: Thirty bovine teeth dentin blocks measuring 5 mm x 5 mm x 1 mm were made with one side completely in dentin substract (20 mm2). The dentin blocks were randomly divided into three groups according to the cementation technique used: CTS+RX (conventional 3-step adhesive + dual-activation resin cement), SBS+RX (single-bottle self-etching adhesive + dual-activation resin cement), and SAC (self-adhesive cement). A photopolymerizable composite resin block with the same dimensions was fixed on the dentin block according to the instructions for each adhesive technique. The dentin-composite resin blocks made with each adhesive technique were separated into subgroups (n = 5) for 7 days (control) and for 6 months of water storage. After each period, the blocks were individually immersed in test tubes containing neutral methylene blue dye for 2 hours. The samples were washed, dried, and evaluated with a stereoscopic magnifying glass, and the amount of infiltrated pigment was analyzed using spectrophotometry (Beckman DU 65). The data were submitted to two-way ANOVA and Tukey’s test (5%). Results: Microleakage level for the conventional 3-step or self-etching technique remained similar for 7 days (18 ± 25 and 43 ± 45 μm, respectively) or 6 months (42 ± 55 and 52 ± 87 μm, respectively). The self-adhesive technique showed higher microleakage levels for 7-day (263 ± 98 μm) and 6-month periods (441 ± 226 μm) compared to other adhesive techniques. There was a statistically significant difference between evaluation times only for the self-adhesive technique. Conclusions: Higher microleakage levels by storage in water occurred with the self-adhesive technique in both evaluation periods. Clinical Relevance: The different microleakage levels promoted at the dentin-composite resin interface should be considered in adhesive clinical procedures in relation to long-term use.