【摘要】 目的:探讨40岁以上单根管下颌第二前磨牙根尖段根管直径和锥度。方法:收集40岁以上单根管下颌第二前磨牙52颗,采用显微CT进行扫描,利用3D Med 2.2软件重建后,分别对距离解剖性根尖孔1,2,3,4,5 mm处进行根管颊舌向和近远中向直径测量,并计算颊舌向、近远中向锥度和观测根管横截面形态变化。结果:根管根尖段平均直径颊舌向大于近远中向(P<0.05),颊舌径和近远中向平均锥度分别为0.09±0.10,0.05±0.03,根尖段80%根管形态为椭圆形。结论:单根管下颌第二前磨牙根尖段个体差异大,颊舌向直径和锥度均大于近远中向,常用根管器械难以兼顾所有根管,根管预备时需引起注意。更多还原

【Abstract】 Objective:To determine the root canal diameter and taper of the apical region of mandibular second premolars in individuals aged 40 years or above.Methods;Fifty-two single root canals of mandibular second premolars in individuals aged 40 years or above were collected for subsequent scanning by micro-CT and re-construction by using the software of 3D Med 2.2.The bucco-lingual and mesio-distal diameters and the taper in the root canals at 1,2,3,4 and 5 mm to the anatomical apex were measured.The morphology of crosssections of the root canals was determined.Results;The average bucco-lingual diameter was considerably greater than that of mesio-distal section(P < 0.05).Mean taper was(0.09±0.10) for bucco-lingual section and (0.05±0.03) for mesio-distal section,respectively.Oval canals in apical region of root canal may account for 80%of all morphologies.Conclusion:Owing to significant between-individual difference in the apical region of root canals of mandibular second premolars,as featured by an increased taper and diameter in buccal-lingual than in mesio-distal section,dental specialists should be alert inasmuch that not all root canals may be thoroughly emptied.更多还原