Study on length of finishing line of abutment teeth prepared for full crown restoration

目的:初步调查成人恒牙全冠预备体肩台周径,便于在全冠预备采取印模前准确裁取排龈线长度进行排龈操作,并对预成冠的制作及为CAD/CAM数字化修复的数据库提供数据支持.方法:收集全冠预备后的合格工作模型,对除第三磨牙之外的所有牙位的全冠预备体终止线(肩台)的外缘用0号缝合丝线和游标卡尺进行周径测量.对左右侧对称牙位、男女之间相同牙位、及不同牙位之间的周径之差进行统计学分析,P＜0.05为差异有统计学意义.结果:获得了全牙列每牙位30颗共计840颗牙的全冠预备体肩台周径值.其中,左右侧对称牙位之间的周径差异无统计学意义P＞0.05,男、女性之间上颌中切牙、侧切牙、第二前磨牙、和下颌第一磨牙之间差异有统计学意义P＜0.05,各个牙位之间差异有统计学意义P＜0.05.结论:本研究初步获得了除第三磨牙外全牙列所有牙位(每个牙位平均30颗牙)的全冠预备体肩台周径值,为临床上精确裁取排龈线长度和需要肩台周径的数字化数据库提供了参考数值.Objective:To investigate the length of finishing line of human abutment permanent teeth for full crown restoration for accurate gingival retraction cords and CAD/CAM crown fabrication.Methods:840 clear working models for full crown restoration were collected,and the outside margin of cervical finishing line of all prepared teeth were measured with thin silk thread and vernier caliper.The mean values of each tooth were recorded and the differences of mean values of teeth among genders,left and right sides,upper and lower teeth,and locations of teeth were analyzed with an independentsamples T test.Results:The length of finishing line of all prepared abutment teeth (30 teeth at each location and totally 840 teeth) were obtained.There were no significant differences in the mean lengths between right and left sides of symmetric teeth,and between male and female (P＞0.05),and there were no significant difference between upper and lower teeth (P＜0.05) except of maxillary incisor teeth,maxillary first premolar,and mandibular first molar(P＜0.05.Conclusion:The lengths of finishing line of prepared abutment teeth for full crown restoration were investigated,and can be a valuable reference for accurate gingival retraction cords and CAD/CAM crown fabrication.北京市自然科学基金中国科技核心期刊(ISTIC)4216-2191