骨性三級咬合異常併發上顎正中門齒逆生埋伏的齒顎矯正介入治療－－病例報告

Orthopedic-Orthodontic Intervention for a Skeletal Class III Malocclusion with an Inverted Maxillary Central Incisor Impaction – A Case Report

第三級異常咬合的成因可能包括下顎突出、上顎不足或是兩者兼具。對於發育中第三級異常咬合而且上顎發育不足之孩童，可以考慮將上顎往前牽引的治療方式。發育中骨性三級咬合如果經由生長調節（growth modification）促進顏面骨向前發育，減少上下顎骨前後向異常程度，也許可避免日後需要進行正顎手術。除此之外，時常使用於第三級異常咬合患者的上顎擴張裝置，可以有效增加上顎牙弓寬度而舒緩牙齒萌發空間不足的問題。本文報告一位中臉部凹陷骨性第三級異常咬合的八歲男孩，其齒列有前牙錯咬、上顎正中門齒阻生及上顎齒列嚴重空間不足達 10 mm 等複雜問題。患者左上正中門齒阻生併發牙根彎曲，我們利用局部固定矯正裝置及上顎弓延伸臂（palatal arch with extension arm）將手術暴露的阻生門齒拉出，之後利用快速上顎擴張器及面罩促進中臉部發育而明顯改善第三級骨性咬合異常程度，後續只在上顎使用固定式矯正裝置治療擁擠齒列，改善上下顎牙齒排列並達成正常咬合關係，顯著改善患者的顏面美觀及咬合功能，由於患者尚有生長潛力，故須持續追蹤其治療結果及下顎生長變化。

The etiologies of Class III malocclusions may result from mandibular prognathism, maxilla deficiency, or both. For growing children with Class III malocclusions characterized with deficient maxilla, the treatment of choice would be protraction of the maxilla. Successful orthopedic treatment through growth modification has increased the possibility to correct developing Class III malocclusion with non-surgical method. In addition, maxillary expansion is frequently required in treatment of Class III malocclusions by increase the transverse width of the maxilla, and possibly enhance the protraction effect of the facemask through disrupting the maxillary suture system. Herein we report a case of 8-year-old boy presenting a concave profile, deficient midface, and Class III malocclusion with anterior crossbite. Severe space deficiency (10 mm) was noted for the upper arch. Moreover, his upper left central incisor was impacted with root dilaceration. Surgical exposure and orthodontic traction of the impacted incisor was performed by using partial fixed appliance and a palatal arch with extension arm. The Class III malocclusion was corrected after the treatment with a rapid palatal expander and a facemask followed by full-arch bonding to gain the space for alignment of second premolars. Class I canine and molar relationship was achieved, and the facial profile was improved. Close follow-up is required to monitor the mandibular growth and the long-term treatment outcome.