| 摘要: | 確認顎位對於矯正醫師在治療病人之前是非常重要的, 時常在矯正完後顎位會有所改變，然而TMJ(顳顎關節）是否會因咬合改變而有生理性之適應性易形及易位的可能性，目前仍具爭論。隨著影像診斷學日益進步， dental CT漸漸地在牙科中被廣泛使用，因此期望藉由cone-beam CT來觀測TMJ在咬合變化後的位置改變以進而了解臨床上顎位變化時的狀況。
本研究六位受試者年齡介於23~31歲，為輕微擁擠安格氏一級不正咬合，由i-CAT cone-beam CT照射後經座標系統轉換後之影像來觀測顳顎關節的變化，照射時間點為矯正治療前、7個月純leveling治療後，使用軟體（Implant MAX4.0 、Mimics）進行2D及3D影像距離及角度評估矯正治療對顳顎關節所造成的位置變化量，採用的顳顎關節2D定位點為Fr(關節窩最高處)、 Ca(髁狀突最前緣處)、Ct(髁狀突最上緣處)、 Cp(髁狀突最後緣處)、Fp(關節窩後緣)、 Fa(關節窩前緣)、 Emtop(關節隆突最尖端點)、 Em50(介於Fr及Emtop之間的關節隆突中點處)。3D定位點為Emtop、Fp、Sco（髁狀突最上緣處）、Aco（髁狀突最前緣處）、Pco（髁狀突最後緣處）、Lco（髁狀突最外緣處）、 Mco（髁狀突最內緣處）。
統計與觀測結果顯示沒有拔牙之一級咬合不正的病人在經過七個月純leveling的矯正治療後顳顎關節透過cone-beam CT影像觀察發現在3D及2D觀測下髁狀突形態變化量沒有差異，在2D觀測下髁狀突位置變化量沒有差異，在3D觀測中發現右側髁狀突有往前方方向移動，左側condyle有往下方方向移動的趨勢(p value: 0.0625~0.125)，且本研究成功利用CBCT建立髁狀突3維空間中髁狀突形態及位置定位的方法，以供未來臨床醫師能利用3D影像來評估矯正治療或其他治療對顳顎關節所造成的影響。
To confirm mandible position is greatly important for the orthodontists before the patient accepts the treatment, because mandible position will change usually after the orthodontic treatment. However, the possibility of temporomandibular joint (TMJ) physically adaptable morphology and position change would alter for the occlusion change. With the imaging modalities development day by day, dental CT was used popularly in the dental field. In this study, we try to understand the clinical mandible position change condition by observing TMJ position change after occlusion alteration detected by cone-beam CT.
The material consisted of i-CAT cone-beam CT of 12 joints in 6 subjects with Class I malocclusion, mild crowding (age range, 23-31years). The cone-beam CT images had been taken before orthodontic treatment and pure leveling seven months later. These images changed by coordinate system were used to observe position and morphology change of temporomandibular joint(TMJ). The cone-beam CT images were digitized on screen by using software programs (Implant MAX4.0、Mimics) to assess position changes under orthodontic treatment, including 2D and 3D linear and angular measurements and certain points were located. The 2D digitized points were Fr(fossa roof), Ca(condylar anterior), Ct(condylar top), Cp(condylar posterior), Fp(fossa posterior), Fa(fossa anterior), Emtop( articular eminence top), Em50(midpoint of articular eminence curvature between points Fr and Emtop). The 3D digitized points were Emtop(articular eminence top), Fp(fossa posterior), Sco(superior mandible condyle), Aco(anterior mandible condyle), Pco(posterior mandible condyle), Lco(lateral mandible condyle), Mco(medial mandible condyle).
The TMJ changes influenced by nonextraction fixed orthodontic treatment of Class I malocclusion after seven months pure leveling resulted in no significant changes in 2D and 3D observation of condylar morphology. No other significant changes in 2D and 3D observation of condyle position were determined(P value>0.05). However while p value was 0.0625 to 0.125, the right condyle was moved trendily to anterior direction and the left condyle was moved trendily to inferior direction during pure leveling orthodontic treatement in 3D observation of condyle position. In this study, the way to establish 3D condylar morphology and locate condyle position by cone-beam CT was set up successfully and hopefully this could be used by future clinical doctors to assess the influence of TMJ in 3D images under orthodontic or other dental treatment. |
