Shiau J Y, Rasmussen S T, Phelps A E, Enlow D H, Wolf G R
Department of Orthodontics, School of Dentistry, Case Western Reserve University, Cleveland, Ohio 44106.
J Dent Res. 1993 Sep;72(9):1291-7. doi: 10.1177/00220345930720090601.
Investigations of the repair of composites have shown that bond strengths can be significantly reduced at an interface involving an aged composite. Brackets placed by some indirect bonding techniques also have an interface involving an aged composite. This study investigated some of the properties of sealant-composite interfaces and parameters affecting these properties independent of other regions and interfaces found in the total enamel-sealant-composite-bracket system using a shear bond-strength test and fractographic analysis. The effects of various pretreatments of 7-day-old composite surfaces on the bond strength and contact angle of a mixed sealant on these pretreated surfaces were determined. Fractured specimens with adhesive failure closest to the point of force application had low bond strengths (17.62 MPa), which could be correlated with surface pretreatment. Preliminary tests showed that acetone pretreatment produced the most consistently strong interfaces with the fewest adhesive failures of this type. Specimens with adhesive failure only in other regions had higher bond strengths (23.41 MPa), which showed no dependence on pretreatment. There was no statistical relationship between contact angle and bond strength. The data coupled with fracture path analysis suggest that: first, the critical region for fracture analysis is that part of the adhesive interface which is closest to the point of force application; second, failure during some dental shear bond strength tests probably occurs as a consequence of tensile stress induced by a bending moment rather than by shear stress; and third, specifying bond strength as breaking load/area may be incorrect.
对复合材料修复的研究表明，在涉及老化复合材料的界面处，粘结强度可能会显著降低。一些间接粘结技术放置的托槽也存在涉及老化复合材料的界面。本研究使用剪切粘结强度测试和断口分析，研究了密封剂 - 复合材料界面的一些性能以及影响这些性能的参数，这些参数独立于全牙釉质 - 密封剂 - 复合材料 - 托槽系统中发现的其他区域和界面。确定了对7日龄复合材料表面进行各种预处理对混合密封剂在这些预处理表面上的粘结强度和接触角的影响。在最靠近施力点处发生粘结破坏的断裂试样粘结强度较低（17.62MPa），这可能与表面预处理有关。初步测试表明，丙酮预处理产生的界面最持久牢固，这种类型的粘结破坏最少。仅在其他区域发生粘结破坏的试样粘结强度较高（23.41MPa），这表明其不依赖于预处理。接触角与粘结强度之间没有统计关系。这些数据与断裂路径分析表明：第一，断裂分析的关键区域是粘结界面中最靠近施力点的部分；第二，一些牙科剪切粘结强度测试期间的破坏可能是由弯矩引起的拉应力而非剪应力导致的；第三，将粘结强度指定为断裂载荷/面积可能是不正确的。
