Hasegawa Yuh, Ezura Akira, Nomintsetseg Batbayar
Department of Orthodontics, The Nippon Dental University School of Life Dentistry at Niigata, 1-8 Hamaura-chou, Chuo-ku, Niigata, 951-8580, Japan.
Orthodontics and Dentofacial Orthopedics, The Nippon Dental University Graduate School of Life Dentistry at Niigata, Niigata, Japan.
Odontology. 2017 Jan;105(1):84-90. doi: 10.1007/s10266-016-0240-y. Epub 2016 Mar 24.
This study aimed to investigate the relationship between the morphological characteristics of maxillary incisors and the anterior occlusion. The study materials comprised dental casts and lateral cephalograms of 26 modern Mongolian females with Angle Class I normal occlusion (mean age, 21 years 5 months). Computed tomography (CT) images of the dental casts were taken with an X-ray micro-CT system (SMX-100CT, Shimadzu, Kyoto Japan). The thickness of the marginal ridges and incisal edges, and the overjet and overbite, was measured on the three-dimensional images of the dental casts. On the lateral cephalogram, maxillary incisor to sella-nasion plane angle (U1 to SN angle), maxillary incisor to nasion-point A plane distance (U1 to NA distance), mandibular incisor to nasion-point B plane distance (L1 to NB distance), incisor mandibular plane angle, and interincisal angle were measured by tracing the left incisors of the maxilla and mandible. Spearman's single rank correlation coefficients were used to investigate any correlation between measurement items for each maxillary incisor. The thickness of the marginal ridges and incisal edges was positively correlated with the overbite. The thickness of the incisal edges was positively correlated with the irregularity index of the maxilla. There were significant negative correlations between overbite and U1 to SN angle, U1 to NA distance, and L1 to NB distance. Significant positive correlations were noted between the overbite and the overjet. In conclusion, there was no strong relationship between the morphological characteristics of maxillary incisors and the anterior occlusion.
本研究旨在探讨上颌切牙的形态特征与前牙咬合之间的关系。研究材料包括26名安氏I类正常咬合的现代蒙古族女性（平均年龄21岁5个月）的牙模和头颅侧位片。使用X射线微型计算机断层扫描系统（SMX - 100CT，日本岛津公司，京都）拍摄牙模的计算机断层扫描（CT）图像。在牙模的三维图像上测量边缘嵴和切缘的厚度以及覆盖和覆合。在头颅侧位片上，通过描绘上颌和下颌的左侧切牙来测量上颌切牙与蝶鞍 - 鼻根平面角（U1至SN角）、上颌切牙与鼻根 - A点平面距离（U1至NA距离）、下颌切牙与鼻根 - B点平面距离（L1至NB距离）、切牙下颌平面角和切牙间角。使用Spearman单等级相关系数来研究每个上颌切牙测量项目之间的相关性。边缘嵴和切缘的厚度与覆合呈正相关。切缘的厚度与上颌的不规则指数呈正相关。覆合与U1至SN角、U1至NA距离和L1至NB距离之间存在显著负相关。覆合与覆盖之间存在显著正相关。总之，上颌切牙的形态特征与前牙咬合之间没有密切关系。
