基于CBCT的下颌后牙区骨内重要解剖结构研究

目的利用锥形束CT（cone beam computed tomography，CBCT）软件分析系统NNTViewer对活体下颌骨三维影像重建测量，研究下颌神经管与邻近解剖结构之间的关系。方法选取100例CBCT影像资料，在下颌骨横截面上测量：①下颌第一前磨牙至同侧第二磨牙各牙牙根中点、根尖与颊舌侧骨壁的距离；②下颌神经管与每个后牙根尖之间及与之相对应的颊舌侧骨壁、牙槽嵴顶和下颌骨下缘的距离。结果下颌第一前磨牙至同侧第二磨牙各牙牙根与颊、舌侧骨壁之间的距离，在牙根中点处分别为1．26—5．02mm、3．74～4．45mm，在根尖处分别为3．85—9．23mm、5．43—7．94mm；下颌第二前磨牙至同侧第二磨牙各牙根尖与下颌神经管之间的距离为5．31～8．19mm。下颌第二前磨牙至同侧第二磨牙各牙根尖下方处的下颌神经管与颊、舌侧骨壁之间的距离分别为3．71～7．62mm、2．91～4．12mm，与牙槽嵴顶之间的距离为17．09-19．22mm，与下颌骨下缘之间的距离为8．22～9．28mm。结论下颌后牙（下颌第三磨牙除外）牙根及下颌神经管与颊侧骨壁之间的距离由前往后逐渐变大。下颌神经管距离第二磨牙远中根最近，距离第一磨牙两根最远；与牙槽嵴顶的距离，在第一磨牙处最大，第二磨牙处最小；与下颌骨下缘的距离，在第二磨牙处最大，第一磨牙近中根处最小。

Applied anatomy study of anatomical structure within the bone in the mandibular posterior area based on CBCT

Objective To study the relationship among the mandibular canal in the mandibular posterior and the ana tomical structure adjacent to it based on cone beam computed tomography （CBCT）. Methods CBCT images of 100 ca-ses were collected from the affiliated Stomatology Hospital of Guangzbou Medical University. At the cross section of the mandibular, the distances from the mandibular canal to the anatomical structure adjacent to it were measured respective ly. Results The distance from the apical to the upper edge of the mandibular canal right below them was 5.31 - 8.19 ram; the distance from half the root to the buccal （lingual） cortex of the mandible was 1.26 - 5.02 mm （3.74 - 4.45 nun） ; the distance from the apical to the buccal （lingual） cortex of the mandible was 3.85 - 9.23 mm（ 5.43 - 7.94） mm; the distance from the lateral border of the mandible canal to the buccal（lingual） cortex of the mandible was 3.71 -7.62 mm （2.91 -4.12） mm; the distance from the upper edge of the mandibular canal to the alveolar crest was 17.09 - 19.22 nun. , and the distance from the inferior border of mandible canal to the inferior border of mandible was 8.22 - 9.28 mm. Condnsion The distances from the buccal cortex of the mandible to the root apex of mandibular pos- terior teeth （ excluding the mandibular third molar）, and to the half length of the teeth root, and to the lateral border of the mandibular canal gradually increased. The distance between the upper border of mandibular canal and the distal root apex of mandibular second molar is the shortest. The distance between the upper border of mandibular canal and the man dibular first molar is the farthest.