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目的:研究上颌第一前磨牙的根管锥度。方法:将离体的101个上颌第一前磨牙髓腔作“颊-舌向”和“近-远中向”X线摄影后输入计算机行图象处理,统计该牙根管全长数值、根管中1/2处颊-舌向直径和近-远中向直径、距根尖端0.5 mm处根管的颊-舌向和近-远中向直径,然后代入公式计算根管的锥度。结果:上颌第一前磨牙根管平均长11.4 mm,根管中段颊-舌径平均宽1.8 mm、近-远中径平均宽0.8 mm,靠近根尖的根管颊-舌径平均宽0.6 mm、近-远中径平均宽0.4 mm;将上述数值代入公式得到该牙根管下段的锥度,在颊-舌象限为0.175,在近-远中象限为0.035。结论:上颌第一前磨牙根管下段并非呈圆锥形空间,而是呈颊-舌径>近-远中径的扁形腔隙;该牙根管预备之初,选择Profile的I号锉较为适宜。
Objective: To study the root canal conicity of maxillary first premolar. Methods: The 101 maxillary first premolar pulp chambers were excised into “cheek - lingual” and “near - far” radiographs and then input to the computer for image processing. The root canal Full-length values, 1/2 at the root canal in the buccal-lingual diameter and proximal-distal diameter, 0.5 mm from the root tip of the root canal in the buccal-lingual and proximal-distal diameter, and then substituted into the formula to calculate the root Pipe taper. RESULTS: The root canal of the maxillary first premolar had an average length of 11.4 mm. The mean diameter of the canal was 1.8 mm in the mid canal and 0.8 mm in the mesial-distal diameter. The mean diameter of the root canal was 0.6 mm , The average diameter of near-distal diameter 0.4 mm wide; the above values were substituted into the formula to obtain the taper of the lower end of the root canal, the cheek - tongue was 0.175, near-far in the quadrant 0.035. Conclusion: The lower root canal of the maxillary first premolar is not a conical space, but a flat lacunar with buccal-lingual diameter> near-distal diameter. At the beginning of preparation of this root canal, Profile I file is more suitable .