Department of Orthodontics, Nihon University School of Dentistry, Tokyo, Japan.
Eur J Orthod. 2011 Dec;33(6):654-9. doi: 10.1093/ejo/cjq152. Epub 2011 Jan 24.
The aim of this study was to investigate the relationship between masseter muscle size and craniofacial morphology, focusing on the maxilla. Twenty-four patients (11 males and 13 females; mean age 27.6 ± 5.6 years) underwent cephalometric analyses. Ultrasonography was used to measure the cross-sectional area (CSA) of the masseter muscle and bite force was measured using pressure sensitive film. The results showed that CSA-relaxed was positively correlated with upper anterior face height (UAFH)/total anterior face height (TAFH) and negatively with lower anterior face height (LAFH)/TAFH and LAFH (P < 0.05). CSA-clenched was correlated positively with SN-palatal, FH-palatal, UAFH/TAFH, and lower posterior face height (LPFH)/total posterior face height (TPFH) and negatively with LAFH/TAFH, LAFH, upper posterior face height (UPFH)/TPFH, and UPFH (P < 0.05). Bite force was positively correlated with LPFH/TPFH and negatively with UPFH/TPFH (P < 0.05). As the masseter became larger, the anterior maxillary region tended to shift downwards relative to the cranial base, whereas the posterior region tended to shift upwards. The decrease in LAFH/TAFH and increase in LPFH/TPFH as the size of the masseter muscle increases may be influenced not only by the inclination of the mandibular plane but also by the clockwise rotation of the maxilla.
本研究旨在探讨咬肌大小与颅面形态的关系，重点关注上颌骨。24 名患者（男性 11 名，女性 13 名；平均年龄 27.6 ± 5.6 岁）接受了头颅分析法。超声用于测量咬肌的横截面积（CSA），并使用压力敏感膜测量咬合力。结果表明，CSA-松弛与上前面高（UAFH）/总前面高（TAFH）呈正相关，与下前面高（LAFH）/TAFH 和 LAFH 呈负相关（P < 0.05）。CSA-紧咬与 SN-腭、FH-腭、UAFH/TAFH 和下后脸高（LPFH）/总后脸高（TPFH）呈正相关，与 LAFH/TAFH、LAFH、上后脸高（UPFH）/TPFH 和 UPFH 呈负相关（P < 0.05）。咬合力与 LPFH/TPFH 呈正相关，与 UPFH/TPFH 呈负相关（P < 0.05）。随着咬肌增大，上颌前区相对于颅底向下移动，而后区向上移动。LAFH/TAFH 的减少和 LPFH/TPFH 的增加可能不仅受到下颌平面倾斜的影响，还受到上颌顺时针旋转的影响。
