Eugénio Sónia, Osorio Raquel, Sivakumar Manickam, Vilar Rui, Monticelli Francesca, Toledano Manuel
Department of Materials Engineering, Instituto Superior Técnico, Lisboa, Portugal.
Photomed Laser Surg. 2010 Feb;28(1):97-102. doi: 10.1089/pho.2008.2270.
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.
Polished dentin surfaces were subjected to the following treatments: (1) 35% phosphoric acid etching for 15 s; (2) laser surface treatment using KrF excimer laser radiation (1 J/cm(2)); and (3) laser treatment under the same conditions followed by acid etching. After treating the dentin, an etch-and-rinse adhesive (Adper Scotchbond 1 XT, 3M ESPE) was applied and composite (Esthet-X, 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 0.5 mm/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.
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 +/- 8.7 MPa) than for laser-treated (13.8 +/- 5.1 MPa) and laser-treated and etched surfaces (19.7 +/- 6.9 MPa). 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.
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.
本研究旨在评估 KrF 准分子激光处理对牙本质与酸蚀冲洗粘结系统之间粘结强度的影响。
对抛光后的牙本质表面进行以下处理：（1）用 35% 磷酸酸蚀 15 秒；（2）使用 KrF 准分子激光辐射（1 J/cm²）进行激光表面处理；（3）在相同条件下进行激光处理后再进行酸蚀。处理牙本质后，应用酸蚀冲洗粘结剂（Adper Scotchbond 1 XT，3M ESPE），并逐层构建复合树脂（Esthet-X，Dentsply Caulk，德国康斯坦茨）。在 37℃ 下储存 24 小时后，从样品上纵向切割出 1 mm² 的梁。微拉伸棒以 0.5 mm/min 的十字头速度进行拉伸加载。粘结强度数据采用单因素方差分析和 Student-Newman-Keuls 检验进行分析（p < 0.05）。在扫描电子显微镜下观察每种表面处理后的牙本质表面以及粘结强度测试产生的断裂表面。
激光处理后的表面呈现出牙本质小管明显封闭的锥形形貌，而酸蚀产生的表面更光滑，小管开放。在激光处理后的牙本质表面应用 35% 磷酸导致表面锥体部分溶解。酸蚀牙本质的平均微拉伸粘结强度（33.7±8.7 MPa）显著高于激光处理组（13.8±5.1 MPa）以及激光处理后再酸蚀的表面（19.7±6.9 MPa）。激光处理组在锥体底部发生内聚破坏的比例更高，而酸蚀样品上主要是混合破坏。
与传统酸蚀技术相比，用 KrF 激光辐射处理牙本质产生的锥形纹理并未提高所测试的酸蚀冲洗粘结系统的粘结强度。
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