Influence of irradiation seguence on physical properties of dual-cured resin cements.

据报道，双固化树脂粘结剂的粘结强度受通过树脂材料的光能的影响。本研究的目的是研究双固化树脂粘固剂的轻活化顺序与树脂粘结剂粘结强度之间的关系。并从临床角度对不同照射方式下的凝结时间和胶膜厚度进行了评价。设计了三个实验来研究以下因素的影响：(1)预拌活化(仅在搅拌前激活液体)，(2)按照制造商的说明进行搅拌后激活，(3)无光激活。在水泥混合料的膜厚度方面，预拌激发组和未激发组之间没有观察到差异。辐照顺序对材料的抗压强度和抗折强度均有影响。随着预混活化度的增加，纵向截面表面的努普硬化数增加。在水泥搅拌前对液体进行预拌辐照，即使在浇筑后不对水泥进行辐照也是有效的。通过活化，液体中的樟脑酚处于反应状态。这种情况显然会产生自由基，并在处理过程中持续。这种活化条件使得预混粘接强度在贴片后不需要辐照。樟脑对苯二酚固化体系的动力学和机理还有待进一步研究。

IT has been reported that the bond strength of dual-cured resin cements is influenced by the light energy through the resin materials. The purpose of this study was to examine the relationship between the order in which a dual-cured resin cement is light activated and the bond strength of the reshin cement. Also, the setting time and film thickness with various irradiation procedures were evaluated from the clinical perspective.Three experiments were designed to study the influence of the following factors : (1) pre-mix activation (activation of only the liquid prior to mixing), (2) post-mix activation according to the manufacturer's instructions, (3) no-light activation.The setting time of cement mix with pre-mix activation was shorter than that with no activation. No difference was observed between the specimen with pre-mix activation and that with no activation regarding the film thickness of the cement mix. The compressive strength and flexural strength were influenced by irradiation sequences. The Knoop Hardness Number on the longitudinally sectioned surface increased with the pre-mix activation. The pre-mix irradiation to the liquid before cement mixing is effective even without irradiation to the cement after placement. Camphoroquinone in the liquid is placed in a reactive condition by activation. This condition apparently generates free radicals and continues during handling time. This active condition makes the pre-mixed bond strength without irradiation after placement.Further studies are needed to define the kinetics and mechanisms of the camphoroquinone curing system.