不同厚度普玛黏结剂对冠固位力的影响

Effect of Different Thickness of PermaCem-Dual on the Crown Retention

目的:探讨不同厚度普玛黏结剂对冠固位力的影响。方法:收集50颗正畸拔除的上颌前磨牙,选取其中30颗牙体按照在代型上涂布间隙剂层数的不同分为A、B、C3组制作金属冠,用普玛黏结剂黏结制成试件,于人工唾液浸泡1个月,循环加载10000次后进行冠固位力的测试。20颗牙体利用CAD/CAM系统制作全瓷冠,依黏结剂厚度分为50μm组和75μm组,分别采用自固化和光固化2种形式黏结制成试件,于人工唾液浸泡1个月后进行冠固位力的测试。结果:A组和B组的固位力明显强于C组的固位力,差异均有统计学意义(P<0.01),但A、B组的固位力差异无统计学意义(P>0.05)。全瓷冠的50μm组的固位力要大于75μm组的固位力,差异有统计学意义(P<0.05)。相同黏结厚度时,光固化和自固化黏结后冠的固位力差异均无统计学意义(P>0.05)。结论:在一定黏结厚度范围内,随着黏结厚度的增加,冠的固位力减小。

Objective： To test different thicknesses of PermaCem-Dual on the effect of crown retention. Methods： Fifty extracted human maxillary premolars from orthodontics were selected. After tooth preparation, 30 dies were made and randomly divided into 3 groups（A, B and C groups）according to different coating layers of dispacer. The metal crowns were produced. The samples were made of the crowns and teeth bonded by PermaCem-Dual, and then storage in artificial saliva for 1 month. All the metal crowns were subjected to 10 000 cyclic mechanical loading,and then they were sent to measure the force at which retention failed.All-ceramic crowns were produced by CAD/CAM system according to adhesive thickness 50 μm and 75 μm. The samples were made of the crowns and teeth were bonded by chemosetting and light-cure. All the all-ceramic samples were measured the force at which retention failed after storage in artificial saliva for 1 month. Results： The retention force was significantly higher in group A and group B than that of group C （P 〈 0.01）, but there was no significant difference between group A and group B （P 〈 0.05）. In the all-ceramic crowns groups, the retention force was higher in group of 50 μm than that of group 75 μm （P 〈 0.05）. As the same adhesive thickness, it showed no difference in the retention force between light-curing and chemosetting group （P 〉 0.05）. Conclusion： The retention force of the crown was decreased as the increase of adhesive thickness in a certain range of adhesive thickness.