Conservative Dentistry Department, Faculty of Odontology, Complutense University, Plaza Ramon y Cajal s/n, Ciudad Universitaria, Madrid, Spain.
Clin Oral Investig. 2010 Apr;14(2):207-16. doi: 10.1007/s00784-009-0284-2. Epub 2009 May 30.
Polymerization contraction of composite resin luting materials is known to produce high stresses in the interfaces being cemented that are described as perpendicular to them. This study describes the effect of shearing strains of curing luting materials on microtensile bond strength (microTBS) of interfaces. A flat surface of labial dentin of bovine incisors was exposed and teeth randomly assigned to A (n = 12) or B (n = 6) groups. Adoro rectangular (2 x 3 x 11 mm) restorative composite resin blocks were cemented (Excite DSC + Variolink II) completely (group A) or partially (group B, only on extremes and center) occupying luting space. After visible light curing, stick compound bars were sectioned perpendicular to interface and submitted to tension until detachment. microTBS decreased from the center to the extremes in group A (Spearman tests p < 0.0008) and not in group B, where microTBS was higher in extremes than in correspondent locations in group A and equivalent to that in group A in the central location. Weibull's analysis showed that m modulus and characteristic stresses also decreased from the center to periphery of restorations in group A. Mechanical resistance of bonded interface of a luting material and dentin decreases peripherally, and this reduction is caused by polymerization contraction.
复合树脂水门汀聚合收缩会在被粘界面产生被描述为垂直于界面的高应力。本研究描述了固化水门汀的剪切应变对界面微拉伸结合强度（microTBS）的影响。暴露牛切牙唇面的平坦牙本质表面，将牙齿随机分配至 A 组（n = 12）或 B 组（n = 6）。将 Adoro 矩形（2 x 3 x 11 mm）修复复合树脂块完全（A 组）或部分（B 组，仅在极端和中心）粘固于牙体（Excite DSC + Variolink II）。可见光固化后，将棒状复合条垂直于界面切割，并在分离前进行张力测试。A 组从中心到极端的 microTBS 降低（Spearman 检验 p < 0.0008），而 B 组则没有，B 组的极端处 microTBS 高于 A 组相应位置，与 A 组中心位置的 microTBS 相当。威布尔分析显示，A 组修复体从中心到周围的 m 模量和特征应力也降低。水门汀和牙本质粘结界面的机械阻力从周围逐渐降低，这种降低是由聚合收缩引起的。
