超声洁治术对金属烤瓷冠边缘微渗漏的影响

Effect of ultrasonic scaling on marginal microleakage of porcelain-fused-to-metal crown

目的探讨超声洁治术对金属烤瓷冠边缘微渗漏的影响。方法选取离体磨牙70颗，随机分成7组（A—G组），每组10颗，按烤瓷冠要求常规牙体预备，制作钴铬合金烤瓷冠。A、B组应用聚羧酸锌水门汀粘结；C、D组应用玻璃离子水门汀粘结；E、F、G组应用树脂粘结剂粘结。各组经冷热循环实验后，B、D、F组按要求进行单次超声洁治术；G组进行3次超声洁治术；A、c、E组作为对照组，不进行超声洁治术。所有实验牙经1％亚甲蓝染色后剖开牙体和烤瓷冠，观测各组的微渗漏深度。结果超声洁治前采用不同粘结剂粘结的牙体微渗漏深度A组〉c组〉E组（均P〈O．05）。与未进行超声洁治术组比较，使用聚羧酸锌水门汀、玻璃离子水门汀粘结，进行单次超声洁治术的牙体微渗漏深度B组〉A组[（3．36＋1．11）mm比（2．55~0．71）mm，P〈0．05]，D组〉c组[（2．96~0．93）mm比（2．02＋0．79）mm，P〈0．05]。而使用树脂粘结剂的牙体进行单次和3次超声洁治术后的牙体微渗漏深度与未进行超声洁治术的牙体比较，即E、F、G3组间差异并无统计学意义（尸〉0．05）。结论超声洁治术对玻璃离子水门汀和聚羧酸锌水门汀粘结的烤瓷冠边缘封闭性产生明显破坏，而对树脂粘结剂粘结的烤瓷冠边缘封闭性无明显影响。

Objective To determine the effect of ultrasonic scaling on microleakage of porcelain- fused-to-metal crown （PFM）. Methods A total of 70 extracted human teeth was randomly assigned to 7 groups for construction of cobalt- chromium alloy PFM, based on the requirements for routine teeth preparation. The teeth were treated with zinc- polyearboxylate cement alone （group A, n=10） or in combination with single ultrasonic scaling（group B, n=10）, glass-ionomer cement alone（group C, n=lO） or in combination with single uhrasonic scaling （group D, n= 10）, or resin cement alone （group E, n= 10） or in combination with single ultrasonic sealing（group F, n=10） or ultrasonic scaling for thrice（group G, n=10）, following hot-cold recycling trial. All the PFM teeth were cross-sectioned following 1% methylene blue staining for assessment of marginal microleakage. Results Prior to ultrasonic scaling, group A yielded most significant marginal microleakage, followed by groups C and E （both P〈O.05）. As compared with the teeth not treated with ultrasonic scaling, zinc- polycarboxylate and glass- ionomer cement followed by ultrasonic scaling resulted in more significant marginal microleakage in group B than that in group A [ （3.36± 1.11 ）mm vs （2.55±0.71）mm, P〈0.05] and in group D than that in group C [ （2.96±0.93）mm vs （2.02±0.79）mm, P〈 0.05 ]. The difference in marginal microleakage of PFM crowns cemented by resin cement followed and not followed by single or thrice ultrasonic scaling was not significant （P〉0.05）. Conclusion Ultrasonic scaling may lead to considerable destruction to marginal sealing of glass-ionomcr and zinc-polycarboxylate cemented, but not resin cemented PFM.