新型套索装置取根管内折断器械的体外评价

In vitro study of a new lasso device for intra-canal broken instrument removal

目的:通过体外实验,评估新型套索装置取根管内折断器械的疗效。方法:选择半年内拔除的完整下颌恒磨牙,拔除后保存于生理盐水中。要求根尖孔已闭合,无隐裂,冠根长18 mm以上,牙根弯曲角度小于90°。根管通畅后,将截短5 mm的30#04锥度镍钛锉尖端折断3 mm于近颊根管中上段。离体牙随机分为套索组和超声组,每组20颗;套索组使用超声工作尖配合Yoshi新型套索装置取折断器械,超声组仅使用超声工作尖取折断器械。记录操作时间,计算取出成功率。折断前、折断后、取折断器械后分别拍摄锥形束CT(CBCT),测量根管容积、根管弯曲度、折断器械断端深度和折断位置。采用SPSS 13.0软件包对数据进行统计学分析。结果:2组间根管弯曲度、断端深度和折断位置无显著差异,折断器械取出成功率无显著差异(P>0.05);套索组操作时间显著短于超声组,根管容积增大显著小于超声组(P<0.01)。结论:套索装置取根管内折断器械有较高的成功率,较单纯使用超声器械能保留更多根管壁牙本质;同时缩短操作时间,可作为取根管内折断器械的辅助手段。

PURPOSE:This in vitro study was aimed to evaluate the efficacy of intra-canal broken instrument removal using a new lasso device.METHODS:Mandibular molars that were freshly extracted within 6 months were used in this study.The teeth were examined under magnification to rule out cracks.Only teeth with closed apices and measured longer than 18 mm from cusp tip to root tip were chosen.Root curvature should be less than 90°.After root canal negotiation,3 mm of a size 30#04 taper nickel titanium file,which was shortened by 5 mm before,was intentionally fractured in the coronal to mid-third of the mesial buccal canal.The teeth were randomly assigned to the lasso and ultrasonic group,each group had 20 teeth.All teeth underwent broken instrument removal procedures.The procedure time and removal success rate were recorded.Cone-beam CT(CBCT)was taken before and after instrument breakage,and after instrument removal.Root curvature,depth of fracture,level of broken instrument,and canal volume were recorded for each group.Statistical analysis was performed using SPSS 13.0 software package.RESULTS:There was no significant difference in terms of root curvature,depth of fracture,level of broken instrument and removal success rate between the two groups(P>0.05).The procedure time was significantly shorter and root canal volume increase was significantly less in the lasso group(P<0.01).CONCLUSIONS:The new lasso device for intra-canal broken instrument removal has a high success rate in this in vitro study.Its usage can preserve more root dentine and shorten treatment time.It can be an useful adjunct to ultrasonic instrument in removing broken instrument from the root canal.