[摘要] 目的：分析上颌第一恒磨牙根管弯曲发生情况、弯曲位置、弯曲方向及弯曲程度。方法：收集南京地区80例上颌第一恒磨牙，在根管中分别插入15#~20#扩大针，拍摄近远中向和颊舌向X线片，用Photoshop 6.0软件测量分析根管弯曲位置、弯曲方向和弯曲角度。结果：1)上颌第一磨牙腭侧根管通畅、较直。 2)远中颊侧根管在近远中方向有80%，颊舌方向有45%出现大于5°的明显弯曲，弯曲位置多位于根中1/3，且近远中向的弯曲明显大于颊舌向(P<0.05)。 3)上颌第一恒磨牙近中颊根颊侧根管在近远中方向、颊舌方向分别有82.5%、77.5%出现大于5°的明显弯曲。两个方向上的弯曲程度无明显差异(P>0.05)。 4)本研究中有35%的标本探通了近颊根舌侧根管，其在近远中向、颊舌向出现明显弯曲的比例达91%、83%。结论：上颌第一恒磨牙四个根管在近远中方向、颊舌方向均有不同程度的弯曲，其第二弯曲出现的情况也各不相同。

    [关键词] 上颌第一恒磨牙 根管 弯曲

    Study of Canal Curvatures in the Roots of First Maxillary Molars.

    SU Han, YAN Xiang, WANG Wen-mei, et al.

    Nanjing General Hospital of Nanjing Military Command PLA, Nanjing 210002

    [Abstract]Objective: To analysis the curvature frequency,position,direction and degree of the maxillary first molars. Mehtods: 80 randomly selected first maxillary molars were used in the study.Radiograph of teeth in buccolingual and mesiodistal directions with 15#~20# reamers in root canals calculated and recorded for both views using Photoshop6.0 by computer. Results: 1) Lingual root canals of first maxillary molars showed no curvatures. 2) Distobuccal root canals were found obvious curve out by the rate of 80% in mesiodistal direction,45% in buccolingual direction.The curvature was often found out in the middle 1/3 region and the curvature in mesiodistal direction was more obvious than that in buccolingual direction(P<0.05). 3) MB1 root canals of the mesiobuccal root canals in maxillary molars were found obvious curve out by the rate of 82.5% in mesiodistal direction,77.5% in buccolingual direction and there is no difference of curvature degree in the two directions. 4) In this research,MB2 root canals of the mesiobuccal root canal were found out by the rate of 35%and they were found obvious curve out by the rate of 91% in mesiodistal direction,83% in buccolingual direction. Conclusion: Majority of the four root canals of first maxillary molars showed curvatures at varing degrees in mesiodistal and buccolingual directions, and the second curvatures of them were different too. ......