下颌骨前突患者下颌管走行及临床价值探讨

目的：：运用锥形束CT(cone-beam CT,CBCT)分析正常人群和下颌骨前突患者下颌神经管轨迹,为临床手术方案的制订和操作时避开重要神经血管提供帮助。方法：选取28例骨性Ⅲ类下颌骨前突患者（男10例,女18例）、20例正常对照组患者（男12例,女8例）,使用CBCT拍摄下颌管影像,从下颌孔至第一磨牙区分为5个平面,在每个层面分别测量下颌管内外径、下颌骨厚度、下颌管至颊舌侧骨皮质及下颌骨下缘的距离。采用SPSS 17.0软件包对测量结果进行统计学分析。结果：下颌骨前突患者自下颌支到下颌角前部逐渐增厚,继续至下颌第一磨牙区逐渐变薄。下颌神经管的内外径自下颌支到下颌体部逐渐变细。颊侧骨皮质厚度自下颌支区域逐渐增厚,到下颌体部继续变薄。下颌骨前突患者与对照组患者下颌管的对比分析显示,骨髓腔宽度与下颌支厚度有显著差异,且具有显著相关性。结论：CBCT能够精确显示下颌神经管的走行及与周边结构的关系,下颌骨前突患者与对照组患者下颌支厚度的差异主要由颊侧骨髓腔宽度造成。

Analysis of mandibular canal in patients with prognathism and its clinical significance

PURPOSE: The aim of this study was to investigate the position and course of mandibular canal in patients with prognathism using cone-beam CT(CBCT),and explore its clinical significance. METHODS: The mandibles of 28 patients with skeletal Class Ⅲ prognathism (10 males and 18 females) and 20 normal people(12 males and 8 females) were analyzed on CBCT. The position and course of mandibular canal from the lowest point of mandibular foramen to the first molar were measured at five specific sections from the mandibular foramen to the mandibular first molar area, including inner and outer diameter, mandibular bone thickness ,distance between mandibular canal and distance to the buccal and lingual bone cortex, and the inferior border of mandible bone. Statistical analysis was performed using SPSS 17.0 software package. RESULTS: The mandibular bones of patients with prognathism gradually thickened from the mandibular ramus to the forepart of the mandibular angle and thinned forward to the position where the mandibular first molar projected on the mandibular bone. Cortical bone of buccal side of the mandibular ramus thickened forward to the mandibular angle and thinned to the mandibular body. The width of buccal bone marrow cavity and diameter of mandibular bone were statistically different between genders. CONCLUSIONS: This study found that the difference between the thickness of the mandibular ramus in patients with mandibular protrusion from the controls was mainly due to the difference between the width of the buccal bone marrow cavity. CBCT can accurately locate the mandibular canal and display anatomic structures.