下颌切牙管的锥体束CT测量研究

Measurement of mandibular incisive canal by cone beam CT

目的通过锥体束CT（CBCT）±量下颌切牙管（MIC）的三维位置、走向和毗邻关系，为下颌颏孔间区手术确定安全区提供依据。方法对83例CBCT影像中的下颌切牙管进行观察和测量，统计下颌切牙管的检出率，在尖牙和侧切牙处分别测量下颌切牙管的直径及到根尖、唇颊侧壁、舌侧壁和下颌骨下缘的距离。结果CBCT上57例（68．7％）显示下颌切牙管，下颌切牙管的直径及距根尖、唇颊侧、舌侧和下颌骨下缘的距离在尖牙处分别为（1.3±0．4）、（8．9±2．9）、（4．3±0．9）、（5．2±1．1）和（8．6±1．5mm，在侧切牙处分别为（1．0±0．3）、（13．3±4．0）、（4．2±0．9）、（5．9±0．9）和（8．9±1．8）mm。结论CBCT可以清晰显示下颌骨中MIC的三维位置、走向及毗邻关系；能为下颌骨颏孔间区手术的术前评估提供重要信息。

Objective This study was conducted to measure the mandibular incisive canal （MIC） by cone beam computed tomography （CBCT） and to assess 3-dimensional structure, course and adjacent structure of the MIC , in order to ensure safe region for surgery of the mandibular interforaminal area. Methods A total of the CBCT images from 83 patients were studied and measured. The detection rates of MIC were calculated The diameter of the MIC and the distances from MIC to the labial and lingual cortices and the inferior border of the mandible and tooth tips were measured at canines and lateral incisors. Results MIC was found in 67.8% of the patients. In the position of canine, the diameter of MIC, the mean distance of the MIC to the tips of the teeth, to the buccal border of the mandible, to the lingual border of the mandible and the inferior border of the mandible were （1.3±0.4）, （8.9±2.9）, （4.3±0.9）, （5.2±1.1） and （8.6± 1.5） mm, respectively. In the position of the incisor, the distance of MIC, the mean distance of the MIC to the tips of the teeth, to the buccal border of the mandible, to the lingual border of the mandible and the inferior border of the mandible were （1.0± 0.3）, （13.3 ± 4.0）, （4.2 ± 0.9）, （5.9 ± 0.9） and （8.9 ± 1.8） mm, respectively. Conclusion CBCT clearly show three dimensional structure, course and adjacent structure of the MIC. Preoperative CBCT can provide vital information for surgery of the mandibular interforaminal area.