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摘要
Objective: The aim of this work was to evaluate the effect of KrF excimer laser treatment on the bond strength between dentin and an etch-and-rinse adhesive system. Materials and Methods: Polished dentin surfaces were subjected to the following treatments: (1) 35% phosphoric acid etching for 15s; (2) laser surface treatment using KrF excimer laser radiation (1J/cm(2)); and (3) laser treatment under the same conditions followed by acid etching. After treating the dentin, an etch-and-rinse adhesive (Adper (TM) Scotchbond (TM) 1 XT, 3M ESPE) was applied and composite (Esthet-X (R), Dentsply Caulk, Konstanz, Germany) build-ups were incrementally constructed. After 24 h of water storage at 37 degrees C, 1 mm(2) beams were longitudinally cut from the samples. Microtensile sticks were loaded in tension at a crosshead speed of 0.5mm/min. Bond strength data were analyzed with one-way ANOVA and the Student-Newman-Keuls test (p<0.05). The dentin surfaces resulting from each surface treatment and the fracture surfaces originated by the bond-strength tests were observed under a scanning electron microscope. Results: Laser-treated surfaces exhibited a cone-shaped topography with a frank occlusion of dentinal tubules, while acid etching produced a smoother surface with open tubules. Application of 35% phosphoric acid on laser-treated dentin surfaces resulted in the partial dissolution of the surface cones. Mean microtensile bond strengths for acid-etched dentin was significantly higher (33.7 +/- 8.7MPa) than for laser-treated (13.8 +/- 5.1MPa) and laser-treated and etched surfaces (19.7 +/- 6.9MPa). A higher percentage of cohesive failures at the base of the cones occurred in the laser-treated group, whereas mixed failures were predominant on acid-etched samples. Conclusion: The cone-shaped texture produced by treating dentin with KrF laser radiation does not improve the bond strength of the tested etch-and rinse adhesive system when compared to the traditional acid-etching technique.
- 出版日期2010-2
