3种黏固剂及牙体预备时机对铸造桩核固位力的影响

Effect of three types of cements and the timing of tooth preparation on the retention of cast posts and cores

目的:评价3种黏固剂及铸造桩核黏固后不同时间牙体预备对桩核固位力的影响。方法:收集因正畸需要拔除的新鲜无龋的下颌单根前磨牙60颗,行根管治疗、根管预备和铸造桩核制作。随机分成3组,每组20颗,分别使用磷酸锌水门汀(ZPC)、聚羧酸锌水门汀(ZPCC)和玻璃离子水门汀(GIC)3种黏固剂黏固桩核,每组内随机分成A、B、C、D4个亚组,每组5颗,分别在黏固后10min、30min、1h、24h进行牙体预备。黏固1周后使用CMT5105微机控制万能试验机对每一标本进行拉伸实验,测出桩从牙根内脱位时的力值,即桩核固位力值。使用SPSS11.5软件包对结果进行统计学分析。结果:桩核黏固后不同时机进行牙体预备,桩核的固位力有显著差别;黏固后24h,牙体预备桩核固位力值显著高于其他组,P<0.05;磷酸锌水门汀黏固组桩核固位力值最大,ZPC>ZPCC,P<0.01;ZPC>GIC,P<0.01;GIC>ZPCC,P<0.05。结论:牙体预备时机对桩核固位力有影响,为了获得较大的桩核固位力值,应尽量在桩核黏固24h后进行牙体预备;3种黏固剂的黏固力大小顺序为ZPC>GIC>ZPCC。磷酸锌水门汀仍不失为一种性能良好、价廉物美的黏结材料,用其黏固桩冠可获得满意的黏固力。

PURPOSE：The aim of this laboratory experiment was to study the effects of the timing of tooth preparation after cemented with three kinds of cements on the retention of cast posts and cores.METHODS：Sixty extracted intact mandibular human premolars with single root were involved in this study.Cast posts and cores were fabricated for each tooth and randomly divided into three groups of 20 specimens each,cemented with three different cements：zinc phosphate cement （ZPC）,zinc poly crylate cement （ZPCC）and glass-ionomer cement（GIC）.Three groups were then randomly divided into four subgroups of 5 specimens each which were subjected to preparation of their cores at 10 minutes,30minutes,1 hour and 24 hours after cement.After one week of cement,each post core system was subjected to an axially directed removal force using an universal testing machine at a speed of 1 mm /min.Difference among the three groups was determined using SPSS11.5 software package.The data was analyzed by one-way variance analysis and Student-Newman-Keuls （SNK） pairwise multiple comparisons.RESULTS：Retention of cast posts significantly increased as the timing of tooth preparation increased for both groups,the value of group D（24h） was significantly greater than the other three groups,P〈 0.05;the posts cemented with ZPC provided significantly greater retention,ZPC〉ZPCC,P〈0.01;ZPC〉GIC,P〈0.01;GIC〉ZPCC,P〈0.05.CONCLUSIONS：The timing of tooth preparation has a significant effect on the retention of cast posts and cores;tooth preparation at 24 hours after cementation is suggested.And in the same timing of tooth preparation,the posts cemented with ZPC provided significantly greater tensile resistance,ZPC is still a high-performance cement to cement post compared to other cements.