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.