錐束電腦斷層在阻生齒治療上的優勢

Application of Cone Beam Computed Tomography(CBCT) in the Treatment of Impacted Teeth

專為口腔頭頸部設計的錐束電腦斷層（cone beam computed tomography, CBCT）為近年來逐漸普遍用於牙科的立體放射影像技術。不同於傳統二維影像，錐束電腦斷層的三維影像能在植牙、正顎手術、阻生多生牙拔除、病理評估、口腔癌與各類顎顏面外科上提供有效的診斷和模擬資訊。阻生齒最常出現的位置是第三大臼齒和上顎犬齒，因其阻生的程度不同可能造成鄰近組織和牙根的傷害。我們提出三則病例報告：21 歲男性左下第二與第三大臼齒阻生；14 歲男性右上犬齒、第二小臼齒、右下第二小臼齒阻生；18 歲女性右上正中門齒、左上犬齒阻生。經過錐束電腦斷層拍攝的高品質影像，分別訂定了拔除、手術暴露合併矯正等不同的治療計畫。錐束電腦斷層的影像提供了醫療團隊準確的立體三度空間資訊，進而減少手術風險；且其影像解析度極佳，卻又不造成過多的暴露劑量，皆是錐束電腦斷層相較傳統平面放射影像應用在阻生齒的重要優勢。

CBCT satisfies various dental requests, including evaluation and imitation of implant surgery, orthognathic surgery, impaction and supernumerary teeth. Besides, it provides sub-millimeter resolution images with reasonable radiation dose. Third molars and maxillary canines are the most common impacted teeth. Impacted teeth may cause root resorption, inflammation reaction of teeth or periodontal tissue. Here we reported three cases: The first case was a 21 y/o male with impacted mandibular 2nd and 3rd molars. The second case was a 14 y/o male with impacted maxillary canine, 2nd premolar, and mandibular 2nd premolar. The third case was a 18 y/o female with multiple impacted maxillary incisors and canines. Various degrees of root resorption were also noted. According to the accurate CBCT 3D images, the impacted teeth per se and their nearby tissues could be clearly shown. Thus, individualized treatment plans, including extraction, or surgical exposures combined with orthodontic treatments were developed. Since CBCT provides abundant information under acceptable radiation exposure, it is no doubt an ideal tool for treatment planning in impaction cases.