上颌第一前磨牙根管颊舌向弯曲情况的研究

目的研究上颌第一前磨牙根管颊舌向的弯曲情况。方法选择100个上颌第一前磨牙为研究对象，开髓并充分暴露根管口后，将1个K型锉插入根管内直至根尖孔处。利用数字成像系统（RVG）拍摄每个牙的近远中向影像，采用Schneider法测量根管的弯曲角度，计算弯曲半径和弯曲部分长度。结果1）100颗上颌第一前磨牙共有176个根管，88个根管存在颊舌向弯曲，其中53个位于根尖1/3；21个根管存在“S”形弯曲，其第一弯曲多见于根中1/3，第二弯曲均见于根尖1/3处。2）颊腭侧根管弯曲情况无统计学差异（P>0.05），但“S”形根管第二弯曲的弯曲情况更为复杂。3）弯曲角度与弯曲半径无相关关系（r=0.002，P>0.05），但与弯曲部分长度呈正相关关系（r=0.489，P<0.01）。结论上颌第一前磨牙根管颊舌向弯曲发生率较高，其中“S”形根管的弯曲情况更为复杂。

Investigation of Root Canal Curvature of Human Maxillary First Premolar in Buccolingual Directions

Objective To investigate root canal curvatures of human maxillary first premolars in buccolingual di-rections.Methods One hundred extracted permanent maxillary first premolars were used.After access preparation,a K-file was inserted into the canals and gently advanced until it reached the apical foramen.Then standardized periapical radiovisiography(RVG) images were taken from mesiodistal direction.The angle of curvature was determined according to the method described by Schneider.The radiu of curvature and length of the curved part of the root canal were calculated.Results 1)The total 50.00%(88/176) of root canal curves were in buccolingual directions,and 53 curves were showed in apical 1/3 of root region.11.93%(21/176) of S-shaped canals were detected,and the first curves were mostly showed in middle 1/3 of root region,the secondary curves were totally showed in apical 1/3 of root region.2)There was no difference of curvatures between buccal and lingual root canals,but the secondary curves of S-shaped canals were more complicated than other root canals.3)There was no correlation between the angle of curvature and the radius of curvature(r=0.002,P>0.05),but significantly correlation between the angle of curvature and length of the curved part of the root canal(r=0.489,P<0.01).Conclusion The occurrence of curved root canals in buccolingual directions may be high in human maxillary first premolars,and the curvatures of S-shaped canals were more complicated than others.