[Asymmetric index analysis on the orthodontic-orthognathic treatment of facial asymmetry patients in skull positioning posterior-anterior radiographs]

Abstract

Objective: To analyze the asymmetry of measurements in facial asymmetry patients with skull positioning posterior-anterior radiographs after orthodontic-orthognathic treatment.

Methods: Posterior-anterior cephalometric radiography and cephalometric analysis were performed in forty-five patients with different degrees of facial asymmetry. A single sample t-test was conducted to compare the asymmetry of measurements before treatment and individual normal occlusion. The measurement and reference values in facial asymmetry patients who underwent orthodontic-orthognathic treatment were summated by analyzing the correlation coefficient. The paired t-test was employed to compare the difference between the two groups before and after the treatment.

Results: Fourteen measurements were significantly different before the treatment and individual normal occlusion (P < 0.05). Me[X] exhibited a higher correlation index of Ag[X] in forty-five cases. Twenty-eight patients showed the main asymmetry in the mandibular body, whereas fifteen patients in the ramus. Two patients showed the main asymmetry in both mandibular body and ramus. Fifteen measurements were significantly different before and after the treatment (P < 0.05).

Conclusion: Facial asymmetry is mainly concentrated in one-third of the surface, primarily manifested in the mandibular body. Orthodontic-orthognathic treatment is preferred when Ag[X] is greater than the minimum reference value of 11.31%, Go[X] is greater than 9.79%, and Me[X] is greater than 5.2 mm.

图 1. 头颅定位后前位片各测量标志点和测量角度

Fig 1 Measurement landmarks and angels in skull positioning posterior-anterior radiograph 1：Cg；2：ANS；3：Umid；4：Lmid；5：L；6：Z；7：Co；8：Cd；9：Ms；10：ZA；11：NC；12：J；13：Pa；14：U6；15：Go；16：Ag；17：Me；a：Cg-Pa-Umid；b：Cg-Co-Me。

图 2. 水平向测量指标

Fig 2 Horizontal measurement 1：Z[X]；2：Co[X]；3：Cd[X]；4：Ms[X]；5：ZA[X]；6：NC[X]；7：J[X]；8：Pa[X]；9：U6[X]；10：Go[X]；11：Ag[X]；12：Me[X]。

图 3. 垂直向及长度测量指标

Fig 3 Vertical and length measurement 1：Cg；2：ANS；3：Umid；4：Lmid；5：L；6：Z；7：Co；8：Cd；9：Ms；10：ZA；11：NC；12：J；13：Pa；14：U6；15：Go；16：Ag；17：Me；a：Co-Go[Y]；b：Co-Me[Y]；c：Go-Me[Y]；d：U6-J[Y]；e：Go-Me[L]；f：Co-Go[L]；g：Co-Me[L]；h：Ms[Y]；i：ZA[Y]。

图 4. 治疗前后面像及头颅定位后前位片

Fig 4 Pretreatment and posttreatment facial photographs and skull positioning posterior-anterior radiograph 上：治疗前；下：治疗后；从左至右依次为正面像、正面微笑像、90°侧貌、45°侧貌、头颅定位后前位片。

图 5. 治疗前口内像

Fig 5 Pretreatment intraoral photographs A：右侧像；B：正面像；C：左侧像；D：上颌面像；E：下颌面像。

图 6. 治疗后口内像

Fig 6 Posttreatment intraoral photographs A：右侧像；B：正面像；C：左侧像；D：上颌面像；E：下颌面像。