Sanggarnjanavanich Seetala, Sekiya Toshiko, Nomura Yoshiaki, Nakayama Takahiro, Hanada Nobuhiro, Nakamura Yoshiki
Postgraduate student, Departments of Orthodontics and Translational Research, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
Assistant professor, Department of Orthodontics, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
Am J Orthod Dentofacial Orthop. 2014 Jul;146(1):82-91. doi: 10.1016/j.ajodo.2014.04.014.
The objectives of this study were to clarify the characteristics of cranial-base morphology in adults with skeletal Class III malocclusion and investigate factors relating to the establishment of a skeletal Class III malocclusion.
Initial lateral cephalograms of women were examined. Subjects with an ANB angle of 0° to 4°, normal overjet and overbite, and a Class I molar relationship were classified as Class I (n = 86). Those with an ANB angle less than -1°, a Wits appraisal less than 2 mm, a negative overjet, and a Class III molar relationship were the Class III group (n = 86) in this study. Angular, linear, and coordinate measurements were made. Multivariate analysis of variance and the Student t test were used to analyze significant differences between the 2 groups. Discriminant analysis, logistic regression analysis, and decision analysis were used to identify which cranial-base and maxillomandibular variables influenced the establishment of a skeletal Class III malocclusion.
The Class III group had smaller values for NSBa, SeSBa, FH-SSe, and FH-SBa. Sphenoidale and basion were more inferior and anterior than those of the Class I group. There was no difference in the anterior and posterior cranial-base lengths between the groups. Greater mandibular length was the first major characteristic in the Class III group, followed by smaller values for SeSBa and NSBa.
Cranial-base morphology in adults with a skeletal Class III malocclusion is different from that in a skeletal Class I malocclusion. Smaller cranial-base angles, steeper posterior cranial bases, more inferiorly positioned sphenoidale, and more anteriorly positioned basion are major characteristics of skeletal Class III malocclusions. These characteristics play important roles in the establishment of a skeletal Class III malocclusion.
本研究的目的是阐明成人骨性III类错牙合患者颅底形态的特征，并探究与骨性III类错牙合形成相关的因素。
对女性的初始头颅侧位片进行检查。ANB角为0°至4°、覆盖和覆牙合正常且磨牙关系为I类的受试者被归类为I类（n = 86）。本研究中，ANB角小于-1°、Wits值小于2 mm、覆盖为负值且磨牙关系为III类的受试者为III类组（n = 86）。进行了角度、线性和坐标测量。采用多因素方差分析和学生t检验分析两组之间的显著差异。判别分析、逻辑回归分析和决策分析用于确定哪些颅底和上颌下颌变量影响骨性III类错牙合的形成。
III类组的NSBa、SeSBa、FH-SSe和FH-SBa值较小。蝶鞍点和颅底点比I类组更靠下和靠前。两组之间颅底前后长度无差异。下颌长度增加是III类组的首要主要特征，其次是SeSBa和NSBa值较小。
成人骨性III类错牙合患者的颅底形态与骨性I类错牙合患者不同。颅底角较小、后颅底较陡、蝶鞍点位置更低、颅底点位置更靠前是骨性III类错牙合的主要特征。这些特征在骨性III类错牙合的形成中起重要作用。
