Chen D C, Lai Y L, Chi L Y, Lee S Y
School of Dentistry, National Yang-ming University, Taipei, Taiwan, ROC.
J Dent. 2000 Nov;28(8):583-8. doi: 10.1016/s0300-5712(00)00041-5.
A decrease in mandibular arch width during forced opening has been documented. However, the contributing factors of mandibular deformations are still unclear. This study investigated the mandibular deformation during mouth opening, and searched for contributing factors related to this phenomenon.
Sixty-two dental students volunteered for this study. A linear variable differential transducer (LVDT) was cemented on the mandibular first molars to record mandibular deformation during mouth opening. Proposed factors including geometric factors of the mandible such as lower gonial angle, mandibular length, symphyseal width and height were measured from cephalometric analysis. Densitometric analysis was performed to detect symphyseal area and bone density.
The changes in width between the mandibular first molars ranged from 20 to 437 microm, which was negatively correlated to the symphyseal width, area, and bone density. Where the lower gonial angle had a positive influence, the arch width changed during mouth opening. A multifactorial model showed a significant correlation between the set of predictor variables (symphyseal area, bone density, and mandibular length) and mandibular deformation.
Mandibular arch width narrowed during forced opening. Subjects with smaller symphysis, lower bone density and longer mandible tend to have larger arch width changes.
已有文献记载在强制开口过程中下颌弓宽度会减小。然而，下颌变形的影响因素仍不清楚。本研究调查了开口过程中的下颌变形，并寻找与此现象相关的影响因素。
62名牙科学生自愿参与本研究。将线性可变差动变压器（LVDT）粘结在下颌第一磨牙上，以记录开口过程中的下颌变形。通过头影测量分析测量包括下颌角、下颌长度、颏部宽度和高度等下颌的几何因素等提出的因素。进行密度测定分析以检测颏部面积和骨密度。
下颌第一磨牙之间宽度的变化范围为20至437微米，这与颏部宽度、面积和骨密度呈负相关。在下颌角有正向影响的情况下，开口过程中牙弓宽度发生变化。多因素模型显示预测变量集（颏部面积、骨密度和下颌长度）与下颌变形之间存在显著相关性。
在强制开口过程中下颌弓宽度变窄。颏部较小、骨密度较低和下颌较长的受试者往往牙弓宽度变化较大。
