增進前上顎根尖下截骨術準確度的模型手術與腭夾板的應用

A Model Surgery Improving the Accuracy of Anterior Maxillary Subapical Osteotomy

林宏政(Hong-Jeng Lin) ； 賴聖宗(Steven Lai)

《中華民國口腔顎面外科學會雜誌》 10卷2期 (1999/09) Pp. 63-78

https://doi.org/10.7104/CJOMS.199909.0063

摘要

實施前上顎根尖下截骨術(anterior maxillary subapical osteotomy)時，前上顎骨段的術後位置，一定會影響手術結果。目前參考文獻資料中，並沒有人報告前上顎根尖下截骨術，術前預定的前上顎骨段位置和術後實際位置的比較。
本文之目的，在提出一精確度不錯的前上顎根尖下截骨術的模型手術製作過程，以及在手術中如何利用腭夾板(palatal splint)來定位並固定前上顎骨段，使它的位置能夠儘量接近術前的計畫位置，並計算前上顎骨段在模型手術的位置與術後實際位置的誤差值。
模型手術過程如下：1.先將石膏齒列模型切削成靜態顎模型(gnathostatic model)，以製模膠(modeling compound)製作齒列模型復位板。2.進行模型手術。3.在模型手術後的齒列模型腭側作一腭側夾板。4.將模擬手術，術後位置齒列模型拆開，以製模膠復位板，將前上顎骨段復位。
本研究的三十位病人，所接受的前上顎根尖下機骨術，均為溫德勒式前上顎截骨術(Wunderer Technique)。術後一週內，攝取病人側面測顱X光片，和術前側面測顱X光片作比較，所得上顎正中門齒切緣位置改變量和模型手術改變量作一比較，發現上顎正中門齒水平移動平均誤差值為：0.5867 mm±0.6720 mm (Mean±sd)，垂直移動平均誤差值：1.0533 mm±0.7413 mm (Mean±sd)。目前文獻上並沒有報告前上顎根尖下截骨術的誤差值，故無法比較。這個誤差值，以平均前後移動量6.85 mm左右的前上顎根尖下截骨術來說，在臨床上是可以接受的，術後的矯正工作也容易掌握。

關鍵字

前上顎根尖下截骨術 ； 準確度 ； 模型手術 ； 腭夾板

並列摘要

The accuracy of the postoperative position of the sectioned bone segment will affect the result of an orthognathic surgery. Reviewing literatures, there is no one presents any data concerning the deviation of the pre-operation predicting position and the real position after surgery of the anterior segment in the maxillary anterior subapical osteotomy.
This article presents a modified model surgery for improving the accuracy of the maxillary anterior subapical soteotomy, and evaluates the deviations of the pre-operation predicting position and the real position after the surgery.
Procedures of the modified model surgery: 1. Trim the upper dental cast as a gnathostatic models; 2. The antero-posterior and vertical location of the upper central incisor edge were measured; 3. Before cutting the model a reproducing plate was made by modeling compound; 4. Section the model, and put the anterior segment at the planned position, then measure the antero-posterior and vertical location of the upper central incisor edge again. At this point, the height discrepancy between the posterior margin of the anterior segment and anterior margin of the posterior segment is consistent with the horizontal cut during the surgery. 5. After a palatal splint was fabricated on this sectioned model, the anterior segment was repositioned by the reproducing plate. Then the gap between the anterior and the posterior segments, bilaterally, is consistent with the vertical bone cut during the surgery.
In the surgery the palatal splint could be used as a checking plate to sure weather the anterior segment is at the planned position or not, and also as a fixation appliance to maintain the segment in place.
In this study, thirty patients receiving anterior subapical osteotomy called Wunderer Technique were took lateral cephalometric X-rayed one week after surgery. Superimposing both X-rays from before and after the operation, we recorded the change in upper central incisors and compared it to that in the modified model surgery. An average discrepancy for upper central Incisor position was found of 0.5867 mm±0.6720 mm (Mean±sd) horizontally, and of 1.0553mm±0.7413mm (Mean±sd) vertically. There have not been discrepancies of anteiror subapical osteotomy recorded in the literature up to date. These discrepancies we found would be clinically acceptable when the changes of total horizontal average was 6.85 mm. Besides, the orthodontic works after surgery would be easy to handle.