成人骨性Ⅲ类错[牙合]颅底和颅颌面结构特征及识别

Characteristics and identification of cranial base and craniofacial structure of skeletal class Ⅲ malocclusion

目的:探讨成人骨性Ⅲ类错牙合颅底和颅颌面的结构特征,及影响骨性Ⅲ类颅颌面型形成的相关颅底结构因素。方法:选取64名成人骨性Ⅲ类错牙合患者(男24例,女40例)作为研究对象,另外选取91名正常人(男32例,女59例)作为对照组。对头影测量片进行描记,确定17个标志点,选取与颅底和颅颌面形态相关的10项角度指标和22项线距指标进行测量并统计分析,对成人骨性Ⅲ类错牙合与正常人的颅底及颅颌面结构特征进行比较和相关性分析。结果:与正常人相比,骨性Ⅲ类错牙合组中前颅底长度(S-N),后颅底长度(S-Ba,S-Ar)以及蝶筛点至鼻根点长度(SE-N)较小,蝶鞍点与颅底点连线(SBa)和蝶鞍点与蝶筛点连线(SSE)的交角(SESBa)、眶耳平面(FH)和蝶鞍点与蝶筛点连线(SSE)的交角(FH-SSE)较小,上颌骨长度较短,下颌骨长度明显较长,均具有显著性差异;同时SE位置更靠下,Ba位置更靠前。相关性分析显示前颅底S-SE、S-N与上颌骨矢状向位置呈明显正相关,后颅底Ba-X与下颌骨矢状向位置呈明显负相关。结论:前颅底中SSE-FH和下颌骨体Co Gn,颅底角SESBa作为参考指标NSBa的补充,可以更好地识别Ⅲ类错牙合。

Objective： To investigate the characteristics of the cranial base in adults with skeletal class Ⅲ malocclusion and analyze the function of factors relating to the formation of skeletal class Ⅲ malocclusion and craniofacial morphology. Methods： Initial lateral cephalograms from 64 adults with skeletal class Ⅲ malocclusion（ 24 males and 40 females） were compared to 91 normal person（ 32 males and 59 females）. The cephalographs were traced,and 17 homologous landmarks were identified and digitized. Cephalometric assessment using 10 angular and 22 linear measurements was performed by means of independent-samples t test and Pearson correlation coefficient. Results： The values of S-N,SE-N,S-Ba,SESBa and FH-SSE were smaller in class Ⅲ malocclusion and SE-Y located more inferior significantly and in addition more anterior in Ba-X. The class Ⅲ group had larger values for the length of mandible and smaller values for the length of maxilla. Correlation coefficients showed that S-SE,S-N was positively related to ANS-X,PNS-X,A-X and Ba-X showed negative correlation with B-X,Pog-X and Go-X. Conclusion： The SSE-FH and Co Gn of the mandible in the anterior skull base,and the SESBa of the skull base,as a supplement to the reference index NSBa,can better identify the class Ⅲ type malocclusion.