冠部预处理对磨牙重度弯曲根管工作长度影响的研究

Study the effect of coronal preflaring on the working length measurement of molar's heavy curved root canals

目的：观察根管冠部预处理对磨牙重度弯曲根管工作长度的影响。方法：选择磨牙根管弯曲度在25°～45°的牙髓炎、根尖炎的460颗患牙588个重度弯曲根管，随机分为A、B、C组，A组153颗磨牙192个根管不预处理冠部，手用不锈钢K锉逐步后退法预备根管，分别测量预备前、后根管长度；B、C组分别用GG钻、机用ProTaper成形锉进行冠部预处理后测量根管工作长度，之后B组151颗磨牙196个根管手用不锈钢K锉逐步后退法预备根管；C组156颗磨牙200个根管机用ProTaper器械完成锉预备根管，两组预备完成后测量根管长度，并对数据进行统计学分析。结果：A组磨牙重度弯曲根管预备前后长度有明显改变（P＜0．01），B、C组经根管冠部预处理后长度改变差异无统计学意义（P＞0．05）。结论：磨牙重度弯曲根管冠部预处理后测量根管工作长度可以提高根管工作长度测量的准确性。

Objective：To observe the effect of coronal preflaring on the working length measurement of molar＇s heavy curved root canals. Method：588 root canals from 460 molar of curvature of 25-45 degrees were choosed to divide into the A、B、C group randomly. The A group 192 root canals from 153 molar were not prepare crown and prepared with K file ,mea-sure the working length before and after the preparation. The B、C group coronal preflaring by Gates-Glidden and Protaper Rotary Instruments,and then B group 196 root canals from 151 molars were prepared with K file,measure the working length before preparation and after the preparation.The C group 200 root canals from 156 molars were prepared with Protaper Rotary Instruments,measure the working length before preparation and after preparing by complete file. Result：there is significant change in group A （P 〈0.01）,and there is no significant differences between B and C group after coronal preflaring （P 〉0.05）. Conclusion：Preflaring the coronal portion of the curved molar＇s root canals could significantlv increase the accurate measurements of the working length.