Tang Na, Zhao Zhi-he, Liao Chun-hui, Zhao Mei-ying
Dept. of Orthodontics, West China College of Stomatology, Sichuan University, Chengdu 610041, China.
Hua Xi Kou Qiang Yi Xue Za Zhi. 2010 Aug;28(4):395-8.
To figure out the differences of the morphological characteristics of mandibular symphysis between Class II and Class III adult skeletal malocclusions with different abnormal vertical skeletal patterns.
109 Chinese female adults of skeletal Class II and Class III were chosen and divided into four groups according to vertical and sagittal skeletal pattern: Class II--vertical-growth-pattern group (n=30), Class III--vertical-growth-pattern group (n=25), Class II--horizontal-growth-pattern group (n=29), Class III--horizontal-growth-pattern (n=25). Lateral cephalograms were taken. The symphyseal widths and heights, along with lower incisor positions were evaluated. Observation and statistics analysis were done to clarify the morphological characteristics of the symphyseal region of different skeletal patterns.
There were morphological differences of symphyseal region between Class II and Class III skeletal malocclusions, but not significant in width and total height. With a vertical-growth-pattern, Class II malocclusions had higher alveolus than Class III, but smaller chin prominence and lower basal bone (P < 0.01). With a horizontal-growth-pattern, Class II malocclusions had higher alveolus (P < 0.05) and larger alveolar top width (P < 0.001). With a same sagittal skeletal pattern, vertical-growth-pattern group had thinner but higher symphyseal region and bigger chin prominence (P < 0.001 in Class II while P < 0.05 in Class III). Besides, a vertical-growth-pattern malocclusion was prone to have a cucurbit-morph chin, of which Id width was larger than basal width (P < 0.01).
There are morphological differences in symphyseal region between Class II and Class III skeletal malocclusions with different abnormal vertical skeletal patterns. The influence of abnormal vertical skeletal pattern to symphyseal morphological characteristics is greater than that of abnormal sagittal skeletal pattern. There is a risk of orthodontic movement of low incisors in vertical-growth-pattern skeletal malocclusion.
探讨不同垂直骨面型的安氏II类与安氏III类成人骨性错牙合畸形下颌骨联合处形态学特征的差异。
选取109名中国成年女性骨性安氏II类和安氏III类患者，根据垂直和矢状骨面型分为四组：安氏II类-垂直生长型组（n = 30）、安氏III类-垂直生长型组（n = 25）、安氏II类-水平生长型组（n = 29）、安氏III类-水平生长型组（n = 25）。拍摄头颅侧位片，评估联合处宽度和高度以及下切牙位置。进行观察和统计分析以明确不同骨面型联合处区域的形态学特征。
安氏II类与安氏III类骨性错牙合畸形联合处区域存在形态学差异，但宽度和总高度差异不显著。垂直生长型时，安氏II类错牙合畸形的牙槽高度高于安氏III类，但颏部突度较小且基骨较低（P < 0.01）。水平生长型时，安氏II类错牙合畸形的牙槽高度更高（P < 0.05）且牙槽顶宽度更大（P < 0.001）。矢状骨面型相同时，垂直生长型组联合处区域更薄但更高且颏部突度更大（安氏II类中P < 0.001，安氏III类中P < 0.05）。此外，垂直生长型错牙合畸形易出现葫芦形颏部，其Id宽度大于基骨宽度（P < 0.01）。
不同垂直骨面型的安氏II类与安氏III类骨性错牙合畸形联合处区域存在形态学差异。垂直骨面型异常对联合处形态学特征的影响大于矢状骨面型异常。垂直生长型骨性错牙合畸形存在下切牙正畸移动的风险。
