Maxillary Molar Protraction with Unilateral Scissors Bite Correction-A Case Report

Protraction of second molar due to premature loss of first molar is a common treatment in orthodontics. However, there are several challenges like maxillary sinus pneumatization, proximity of roots and the maxillary sinus, root resorption and variable degrees of tipping after treatment. Brodie bite is also a challenging problem in orthodontics. If left untreated, many complications such as uneven wear of the enamel and teeth elongation might occur. This case report presents a 28-year-old male patient with maxillary sinus pneumatization from a retained root of maxillary first molar, combined with buccal crossbite of the 2^(nd) and 3^(rd) molars. Also, mild crowding of both arches and mild protrusive profile were noted. The treatment was divided into two phases. Sectional braces and wires with the aid of upper right palatal mini-screw and lower right buccal mini-screw was performed at the first stage for 3 months to correct the right molar crossbite. Followed by the full mouth orthodontic fixed appliance combined with upper right mini-screw for 2 years and 4 months at second stage, upper right second molar was successfully protracted through the maxillary sinus. The protrusive profile was also corrected using whole arch distalization by mini-screws. The retention records of one-year follow-up showed stable results.

關鍵字

maxillary sinus pneumatization ； molar protraction ； molar crossbite

並列摘要

由於第一大臼齒的早期缺失使得第二大臼齒需要在矯正療程中合併前拉，是一個常見的矯正治療。然而，在治療的過程中可能會面臨很多的挑戰，像是：上顎竇氣室化、牙根與鼻竇的相鄰性、術後可能會有牙根吸收或牙根傾斜的問題等等。在矯正領域中，頰性錯咬也是一個相當具有挑戰性的問題，如果放置不處理，可能會有不均勻的琺瑯質磨耗與對咬牙過度萌發等併發症。本病例報告為一位28歲男性，右上第一大臼齒殘根拔除導致上顎鼻竇氣室化，合併右上第二大臼齒與第三大臼齒頰側錯咬，同時有雙側牙弓輕微擁擠與外觀前突的問題。整體治療流程可分為兩個階段：第一階段，利用局部傳統矯正裝置合併右上顎側與右下頰側骨釘治療臼齒錯咬的問題，共耗時三個月；第二階段，使用全口矯正裝置合併兩年又四個月的右上骨釘，成功將右上第二大臼齒沿著上顎竇做前拉。外觀前突的問題也在骨釘完成整體牙弓遠心移動的過程得到解決。治療後一年的追蹤紀錄顯示治療結果的穩定。

並列關鍵字

上顎鼻竇氣室化；臼齒前拉；臼齒錯咬

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