桩核粘固后不同间隔时间预备对冠方微渗漏的影响

目的 比较铸造桩核粘结后不同间隔时间备牙对冠方微渗漏的影响。方法 66颗离体单根管下颌前磨牙，其中60颗随机分为6组，制作铸造桩核。2、4、6组分别于铸造桩 核用磷酸锌水门汀粘结2、10、30 min后备牙，1、3、5组桩核粘结后不备牙作为对照，其余6颗牙分别作为阴性及阳性对照。所有牙齿经1周染色后，作透明处理，评价冠方微渗漏的情况。结果 间隔时间相同的各备牙组与不备牙组的微渗漏差异有统计学意义（P<0.05）；不备牙组之间的微渗漏差异无统计学意义（P>0.05）；间隔2 min和10 min备牙组与间隔30 min备牙组的微渗漏差异亦有统计学意义（P<0.05）。结论 备牙时高速手机产生的震动会明显增加桩冠的冠方微渗漏，桩核粘结后备牙的间隔时间至少为10～30 min。

Influence of Timing Preparation on Coronal Microleakage of Cemented Cast Posts and Cores

Objective To investigate the effect of coronal microleakage of cemented cast posts and cores after different interval time preparation. Methods Cast posts and cores were fabricated for 60 of 66 extracted single-root mandibular premolars which randomly divided into 6 groups and cemented with zinc phosphate cement. The other 6 specimens acted as negative control group and positive control group. After 2, 10, 30 minutes interval time, preparation would do for preparation groups and three control groups without preparation. After dying and making transparent, the assessment of the coronal microleakage was done. Results The results showed significant differences betwecn each prepared group and unprepared group. No differences were defected in 3 unprepared groups. But significant differences were recorded between after 2, 10 minutes preparation groups and 30 minutes group. Conclusion High-speed preparation had a sign/ficant negative effect on the coronal microleakage of posts. The interval time of preparation after cemented cast trusts and cores was at least between 10 and 30 minutes.