青少年颞下颌关节形态特征与下颌骨三维方向生长的相关性研究

Correlation between morphological characteristics of the temporomandibular joint and three-dimensional mandibular growth in adolescents

目的通过测量具有不同颞下颌关节形态特征的青少年生长高峰期前后下颌骨在三维方向的生长量,探索颞下颌关节形态特征与下颌骨生长潜力的关系。方法选取生长发育正常、未经正畸治疗的青少年横向样本226例,收集各样本的锥形束计算机断层扫描(CBCT)资料,根据蝶枕软骨联合融合程度分为生长期前组及生长期后组,测量并计算髁突位置、髁突高颈比、髁突角、髁头直立角,根据结果分为具有不同颞下颌关节形态特征的各组,测量分析各组下颌骨在三维方向的生长量。结果无论髁突在关节窝中处于何种位置,生长高峰期前后,均可观察到下颌长度及高度显著增长,仅在髁突非正中位时,观察到下颌宽度增长差异具有统计学意义;髁突短而粗,可观察到下颌在三维方向生长均显著,髁突长而细,可观察到下颌骨长度与高度显著增长而宽度增长差异无统计学意义;髁突角较大,可观察到下颌在三维方向生长均显著,髁突角较小,可观察到下颌长度与高度增长显著而宽度增长差异无统计学意义;髁头直立角较大,可观察到下颌的长度及高度增长显著而宽度增长差异无统计学意义,髁头直立角较小,可观察到下颌长度与宽度增长显著而高度增长差异无统计学意义。结论颞下颌关节形态特征可作为预测下颌骨生长潜力的参考指标,具有不同颞下颌关节形态特征的下颌骨在生长高峰期间在各方向的生长量存在差异。

Objective The aim of the study was to explore the correlation between temporomandibular joint(TMJ)morphological characteristics and mandibular growth potential by measuring the three-dimensional growth of the mandible before and after the growth spurt in adolescents with different TMJ morphological characteristics.Methods A transverse sample of 226 adolescents with normal growth and without orthodontic treatment was selected,and the cone beam computed tomography(CBCT)image of each patient was collected.All the samples were divided into pregrowth groups and post-growth groups based on the stages of spheno-occipital synchondrosis fusion.The condylar position,condylar height-neck ratio,condylar angle,and condylar head vertical angle were measured and calculated.According to the measurement results,all the samples were divided into groups with different TMJ morphological characteristics,and each group’s mandibular three-dimensional growth was measured and analyzed.Results Regardless where the condyle was located in the joint fossa,a significant increase in mandibular length and height was observed during the growth spurt.When the condyle was not in the median position,the growth of mandibular width was statistically significant.The growth of mandibles with short and thick condyles was significant in all directions,whereas the growth of those with long and thin condyles was statistically significant in length and height but not in width.The growth of mandibles with relatively large condyle angle was statistically significant in all three-dimensional directions,whereas those with relatively small condyle angle showed statistical significance in length and height but not in width.Mandibles with relatively large condylar head vertical angle showed significant growth in the length and height but not in width,whereas mandibles with relatively small condylar head vertical angle had statistically significant length and width growth,with no statistical significance in height.Conclusion The morphological characteristics of the TMJ can be used as a reference index to predict the growth potential of the mandible.The growth volume of mandibles with different TMJ characteristics changes in various directions.