利用CBCT对不同年龄组下颌偏斜患者髁突进行的三维形态研究

Condylar 3-dimensional morphological analysis for different-age-group patients with mandibular deviation by Cone Beam Computed Tomography

目的建立不同年龄组下颌偏斜患者CT三维重建模型,测量、分析不同年龄组下颌偏斜患者髁突形态三维特征,并比较双侧髁突对称性。方法选择3个不同年龄组:替牙组(8～11岁)和年轻恒牙列组(11～16岁),成人组(18～30岁)的偏颌患者各12例,进行CBCT扫描,采集颅面部DICOM数据,使用Sim plant对骨组织进行三维重建和参数测量,对结果进行统计学分析。结果不同年龄组偏颌患者髁突三维形态存在差异性。替牙组下颌偏斜患者两侧髁突形态无明显差异;年轻恒牙列组髁突高度、髁突内外径、下颌支高度、髁突后斜面长度、髁突后斜面倾角偏斜侧与对侧比较出现了差异,双侧髁突形态发生了非对称性改变;成人组下颌偏斜患者双侧髁突形态发生了明显的非对称性改变,偏斜对侧髁突高度、下颌升支高度、髁突内外径较偏斜侧增大,髁突后斜面长度、后斜面倾斜角较偏斜侧减小。结论下颌偏斜可引起髁突的非对称性改建,从替牙组到成人组,下颌偏斜有从下颌移位向骨骼异常发展的趋势,故下颌偏斜患者应该早期矫治。

Objective To evaluate asymmetry of bilateral condyle in different-age-group patients with mandible deviation based on 3D model reconstructed with 3D CT images.Methods A total of thirty-six patients diagnosed with mandibular deviation were included,and they were divided into three groups by age.The first group included twelve children aged 8 to 11 years old in their mixed dentition period;the second group included twelve youngs aged 11 to 16 years old with early permanent dentition;the third group included twelve adults aged 18 to 30 years old.Every person was scanned with 3-dimensional cone-beam computed tomography（CBCT）.Craniofacial DICOM data were acquired.Three-dimensional reconstruction and parameter measurement were done to bone tissue with Simplant software.The results were analyzed statistically.Results There were differences in condylar morphology among different-age-group patients.There was no significant difference in condylar morphology on two sides in mixed dentition period.In the young permanent dentition stage,there was difference in condylar height,condylar transverse dimension,mandibular ramus height,and condylar gradient of back bevel between the contralateral side and ipsilateral side.Bilateral condylar morphology changed asymmetrically.There was significant asymmetrical difference of bilateral condylar morphology in adult patients with mandibular deviation.Compared with the ipsilateral side,condylar height,mandibular ramus height,and condylar transverse dimension were larger on the contralateral side while both the inclination and length of the posterior cant of condyle on the contralateral side were smaller.Conclusions Mandibular deviation may lead to asymmetric remodeling in the condyle.From patients in mixed dentition period to adult patients with mandibular deviation,there is a trend from the mandibular shift to the skeleton abnormal development,so patients with mandibular deviation should receive early treatment.