Daub Jacob, Berzins David W, Linn Brandon James, Bradley Thomas Gerard
Department of Developmental Sciences, Marquette University, Milwaukee, WI 53201-1881, USA.
Angle Orthod. 2006 Mar;76(2):295-300. doi: 10.1043/0003-3219(2006)076[0295:BSODAI]2.0.CO;2.
Thermocycling simulates the temperature dynamics in the oral environment. With direct bonding, thermocycling reduces the bond strength of orthodontic adhesives to tooth structure. The purpose of this study was to evaluate the shear bond strengths (SBS) of one direct and two indirect bonding methods/adhesives after thermocycling. Sixty human premolars were divided into three groups. Teeth in group 1 were bonded directly with Transbond XT. Teeth in group 2 were indirect bonded with Transbond XT/Sondhi Rapid Set, which is chemically cured. Teeth in group 3 were indirect bonded with Enlight LV/Orthosolo and light cured. Each sample was thermocycled between 5 degrees C and 55 degrees C for 500 cycles. Mean SBS in groups 1, 2, and 3 were not statistically significantly different (13.6 +/- 2.9, 12.3 +/- 3.0, and 11.6 +/- 3.2 MPa, respectively; P > .05). However, when these values were compared with the results of a previous study using the same protocol, but without thermocycling, the SBS was reduced significantly (P = .001). Weibull analysis further showed that group 3 had the lowest bonding survival rate at the minimum clinically acceptable bond-strength range. The Adhesive Remnant Index was also determined, and group 2 had a significantly (P < .05) higher percentage of bond failures at the resin/enamel interface.
热循环模拟口腔环境中的温度动态变化。对于直接粘结，热循环会降低正畸粘结剂与牙体组织之间的粘结强度。本研究的目的是评估热循环后一种直接粘结方法和两种间接粘结方法/粘结剂的剪切粘结强度（SBS）。将60颗人类前磨牙分为三组。第1组的牙齿用Transbond XT直接粘结。第2组的牙齿用化学固化的Transbond XT/Sondhi快速固化剂进行间接粘结。第3组的牙齿用Enlight LV/Orthosolo进行间接粘结并光固化。每个样本在5摄氏度至55摄氏度之间进行500次热循环。第1、2和3组的平均SBS在统计学上无显著差异（分别为13.6±2.9、12.3±3.0和11.6±3.2兆帕；P>.05）。然而，当将这些值与先前一项使用相同方案但未进行热循环的研究结果进行比较时，SBS显著降低（P=.001）。威布尔分析进一步表明，在临床上可接受的最低粘结强度范围内，第3组的粘结存活率最低。还测定了粘结剂残留指数，第2组在树脂/牙釉质界面的粘结失败百分比显著更高（P<.05）。
