Abstract
Objectives: The aim of this in vitro study was to assess micro-shear bond strength (mu SBS) of tertiary-butanol-based adhesive under moist and dry conditions and correlate the results to resin-tags surface-area. Methods: Thirty-extracted human molars were used. Flat dentin surfaces were prepared on buccal and occlusal surfaces ready for bonding. Specimens were randomly divided into three-groups; G1: Prime&BondNT, applied to moist dentin (control), G2: XPBond, applied to moist dentin, and G3: XPBond, applied to dry dentin. Etch&Rinse technique was used for both adhesives as per manufacturer's instructions. For G3, dentin was air-dried for 10s before XPBond application. Three-microcylinders of composite-resin (TPH A2 shade, Dentsply) were bonded to buccal dentin of each specimen for mu SBS testing, while 2mm composite-resin was bonded to occlusal dentin for tags surface-area analysis. Curing was performed for 40s (LED, Bluephase, Ivoclar/Vivadent). All specimens were stored in distilled water at 37 degrees C for 24h. mu SBS testing was performed using testing machine (Model LRX-plus; Lloyd-Instruments Ltd., Fareham, UK) and data were recorded using software (Nexygen-MT Lloyd Instruments). Each specimen was then sectioned mesio-distally to expose resin-dentin interface, examined at 1500X using Environmental-Scanning-microscope, and tags surface-area were calculated. Data were analyzed by Pair-wise Newman-Keuls multiple comparison and regression-analysis (P<0.05). Results: G2 (29.06MPa) showed insignificantly higher mu SBS than G1 (25.45MPa), while G3 (17.3MPa) showed significantly the lowest mu SBS. G3 produced significantly highest tags surface-area (200.4 mu m(2)) compared to G1 (149.4 mu m(2)) and G2 (94.54 mu m(2)). Conclusion: - Butanol-based adhesive bonded to moist dentin, produced high mu SBS and hybrid layer with short resin-tags that showed a perfectly infiltrated and sealed dentin-resin interface, - bonding to dry dentin showed lower mu SBS, - there was significant correlation between tags surface-area and mu SBS for G1&G2, - no correlation was found for G3. Acknowledgement: Dentsply/Caulk. The purpose of this in vitro study was to compare micro-shear bond strength (mu SBS) of a tertiary-butanol-based adhesive to a 2-step etch and rinse one, under moist and dry conditions and correlate the results to resin-tags surface-area.