下颌第一磨牙近中根根管形态的研究

目的：评价下颌第一磨牙近中根根管形态。方法：取100个下颌第一磨牙近中根,印度墨水染色,硝酸脱钙,酒精脱水,于水杨酸甲脂透明,体式显微镜下观察。结果：Ⅰ类根管9例,Ⅱ类根管31例,Ⅲ类根管1例,Ⅳ类根管49例,Ⅴ类根管2例,Ⅵ类根管6例,无Ⅶ、Ⅷ类根管。根管侧支41例,其中75%位于根管冠1/3,21.95%位于根管中1/3,68.03%位于根管尖1/3。根管峡部58例,13.79%位于根管冠1/3,75.86%位于根管中1/3,10.34%位于根尖1/3。结论：下颌第一磨牙根管形态复杂,根管峡部多位于根管中部。

Root Canal Morphology of Single-Mesial-rooted of the Mandibular First Molar

Objective：To evaluate root canal morphology of single-mesial-rooted of the mandibular first molar.Methods：100single-mesial-rooted of the mandibular first molars were selected.The roots were injected with India ink,demineralized with nitric,dehydrated with ethanol,cleared with methylsalicylate and evaluated under magnification（×3）.Results：There were 9 cases in typeⅠ,31 cases in typeⅡ,1 case in typeⅢ,49 cases in typeⅣ,2cases in typeⅤ,6 cases in typeⅥ,no case in typeⅦ and typeⅧ.The number of lateral canal was 41,in which there were 9.75% in coronal third,21.95% in middle third and 68.30% in apical third.The number of isthmus was 58,in which there were 13.79% cases in coronal third,75.86% in middle third,10.34% in apical third.Conclusion：The single mesial-rooted of the mandibular first molar usually has two canals.The isthmus were more concentrated on middle third of root canal.