在齒顎矯正治療時，對於關閉因拔牙所產生的空間，其治療力學通常有兩種：就是線圈機制及滑動機制。
雖然在滑動機制的最大優點是僅需最少的彎線、較少的門診時間、有足夠的空間起動、以及容易達到牙齒的整體移動。其缺點包括了中繼的力量系統、橡皮筋或彈力線的開始時過度起動傾向、因磨擦力產生的黏連、和搖擺效應。
隨著矯正產品的發展，如暫時錨定裝置在關閉空間時，扮演著良好的矯正錨定，不管在何種矯正力學下，解決了錨定的問題，以及容易達成前牙整體的往後移動。雖然暫時錨定裝置(TAD)和其他矯正產品提供了這些好處，仍然時有爭論某一矯正力學誰屬優劣和差異，尤以牙齒移動的原理和速度。因此現在的文獻仍無明確指出誰在牙齒移動和拔牙後空間關閉是最有效。
目的：
本實驗目的是比較在實際的臨床情況下，以不同的矯正力學機制，比較牙齒的移動效應。
材料與方法：
本實驗共有六組臘質矯正操作模型以比較以不同矯正力學對牙齒移動的比率及形式。根據在本實驗的嘗試錯誤的模擬測試結果，選定以300公克的往內拉力量。
結果：
雖然本研究中以三種不同的矯正力學進行，但在浸泡程序後的結果並無顯著差異。而從曲線圖中顏示出以下的明顯差別：
1. 滑動力學在前牙弓長度上呈現最多的收縮，但在拔牙後的空間並無大量收縮。
2. 犬齒及臼齒間的寬度應維持接近起始時的大小，以確定其穩定度。
3. 連續性蕈狀線圈則對牙弓寬度呈現最少的改變。
4. 雖然可以用牙弓分段化機制的力學方法來快速關閉空間，但是有明顯的牙弓變形，因此應格外注意。
5. 在垂直方向的移動，所有力學均對後牙產生壓入效果，以及前牙的拉出，而連續性蕈狀線圈則對前牙有最明顯的拉出。
6. 相較於牙齒的長時間移動模式與短時間一次過移動模式應有差異。
結論：
此三種矯正力學在統計上雖無差異，可能歸因於樣本不足，但曲線圖卻有明顯差異，所以在臨床上仍可能有提供參意義！
Treatment mechanics for closure of extraction spaces are accomplished in two approaches, namely: the loop mechanics and the sliding mechanics.
With the development of orthodontic products such as Temporary Anchorage Device (TAD), en-masse retraction of the anterior teeth were easily achieved. However, in spite of the benefits offered by the TADs, there is still a constant debate between the superiority and difference of one type of orthodontic mechanics over another especially in the rate and response of tooth movement. Thus, there is still no clear consensus on the most efficient way to move teeth and close the extraction spaces in the literature.
Purpose:
The purpose of this study is to compare the tooth movement responses with different orthodontic mechanics that were used in typical clinical situation.
Materials and Methods:
Six Innovated wax Typodont Models (ITM) as study samples used in this study to evaluate the tooth movement responses with different orthodontic mechanic. A retraction force of 300 grams was chosen based on the results of the pilot study.
Results & Discussion:
Although the results of this study showed no significant difference between the 3 orthodontic mechanics after the dunking process due to small sample size, the plotted graph showed the following distinct differences:
1. Sliding mechanics showed the greatest reduction of the anterior arch length but the amount of extraction space did not shorten much.
2. Inter-canine width and inter-molar width should be kept as close to the starting dimension as possible to ensure stability.
3. The continuous mushroom loop mechanics showed the least amount of arch width change.
4. Although rapid space closure was seen with segmented arch mechanics, distortion of the arch form was very noticeable with segmented arch mechanics.
5. Extrusion of the anterior teeth and intrusion of posterior teeth were seen most in continuous mushroom loop mechanics.
6. The long term tooth movement pattern seemed to be different with the initial tooth movement pattern was seen in this study.
Conclusion:
Although there is no statistical difference between the 3 orthodontic mechanics due to the small sample size of this study, the plotted graphs showed distinct differences of each of the orthodontic mechanic variables which may provide valuable clinical reference.
