烧结次数对金属烤瓷冠强度的影响

目的:通过金属烤瓷冠的破坏试验,研究烧结次数对金属烤瓷冠强度的影响.方法:用Instron万能材料测试机对不同烧结次数金属烤瓷冠试件进行破坏试验,测试其折裂时的力值,并对破坏试验力值进行统计分析.结果:不同烧结次数金属烤瓷冠的破坏试验力值差异有显著性(P＜0.01),烧结4次和6次组的破坏试验力值均分别大于烧结8、10、12次组(P＜0.01),但烧结4、6次组间及烧结8、10、12次组间的破坏试验力值差异无显著性(P＞0.05).结论:超过一定的烧结次数时,烧结次数的增加对金属烤瓷冠的强度有影响.烧结4～6次时金属烤瓷冠的强度最大,随烧结次数的增加,当烧结超过8次时,金属烤瓷冠的强度降低.在满足临床需要的前提下,应尽量减少金属烤瓷冠的烧结次数,最好控制在8次以下.

Effects of the number of firing on strength of procelain-fused-to-metal crown

Objective: By destruction tests on procelain-fused-to-metal crown (PFM), to study the effects of the numberof firing on PFM strength. Methods: With Instron testing machine, destruction test on each model with different numberof firing is performed to test fracture force values. Statistical analysis of those values was performed. Results: There wassignificant difference between destruction test values on models with different number of firing (P<0.01). The destructiontest values of group A and B were sighificantly larger than that of group C, D and E (P<0.01); there was no significantdifference between group A and B, so was group C, D and E (P>0.05). Conclusions: When certain number of firing isexceeded, increasing the number of firing has effects on PFM strength. PFM strength is maximum when firing number is4-6. When firing exceeds 8 times, its strength decreases. With the premise of satisfying clinical requirements, the numberof PFM firing should be as minimum as possible, and had better be not more than 8.