上顎單側多顆阻生齒在矯正治療過程中之骨內移動現象－－病例報告

Intraosseous Movement of Multiple Impacted Teeth Occurred in Unilateral Maxilla During Orthodontic Treatment– A Case Report

同側多顆阻生牙之矯正治療極具挑戰性，常須配合大範圍的阻生齒露出手術，及精準的矯正力學應用，始能將其拉出並保留。本病例報告為14歲男性，左上顎有殘留乳犬齒、第一及第二乳大臼齒，其中第一乳大臼齒有鄰接面齲齒及牙齦膿腫；環口Ｘ光顯示水平阻生恆犬齒、第一小臼齒，及垂直阻生第二小臼齒。我們先拔除乳牙及清除膿腫以去除阻生病因，第二小臼齒隨即萌出；矯正牽引低位第一小臼齒時，水平高位阻生犬齒出現自發性骨內移動現象，逐漸轉直並往咬合面萌發，而後搭配犬齒牙齦切除術即完成治療，大幅縮小手術範圍及複雜的矯正牽引。據此經驗，若牙周韌帶中之夏庇氏纖維（Sharpey’s fibers）維持完整，矯正牽引鄰近低位阻生牙時，即有機會引導高位阻生齒自發性萌出。

The orthodontic treatment of unilateral multiple impacted teeth is challenging. It is often accompanied with a wide range of surgical exposure for impacted teeth. We reported a 14-year-old male patient who had a retained primary canine, first and second molars in left maxilla, complicated with proximal caries and gingival abscess over the primary first molar. The panoramic radiography revealed with a horizontally impacted canine, first premolar and vertically impacted second premolar in left maxilla. After relive the underlined pathogenesis of the tooth impaction by removing the primary teeth and abscess, the second premolar erupted subsequently. During traction of the inferiorly impacted fist premolar, the superior horizontally impacted canine uprighted gradually and moved downward to the occlusion. The spontaneously intraosseous movement of the impacted canine allowed us to perform only gingvectomy instead of the aggressive wide surgical exposure. By preserving the integrity of periodontal ligament and Sharpey's fiber, the highly impacted tooth might erupt spontaneously during the traction of the adjacent lower impacted tooth.