- 學位論文
齒顎矯正用LH鎳鈦合金線電解拋光處理及其力學特性之研究
Study on Electrochemical Polishing and Mechanical Properties of LH Nickel-Titanium Alloy Wire for Orthodontics
摘要
鎳鈦合金(Nickel-Titanium)在生醫領域具有廣泛的應用，也被製作成齒顎矯正線，鎳鈦合金線比起不鏽鋼線彈性佳且可隨口腔溫度調整彈性，可利用形狀記憶的特性矯正牙齒，瞬間作用力小可減輕矯正過程中的疼痛感。然而矯正治療期間牙齒與矯正線仍然有很多死角難以清潔，因此必需使用表面處理的方法改善矯正線的表面粗糙度，目的在於使病患容易清潔，又根據牙齒矯正的臨床結果指出Omega loop對於第三類咬合不正的患者是有效的治療方式，比一般矯正時間還要快速。本研究使用電解拋光的方式改善鎳鈦合金矯正線的表面粗糙度，以訊號產生器、功率放大器及多功能電錶組成量測電化學反應曲線的系統，根據量測的結果選擇適合的電壓範圍後使用直流/交流電源供應器進行電解拋光實驗，固定電解液濃度(2 M)、電解液溫度(50 °C)及電壓(2.1 V)，改變電極間隙(1 mm、2 mm、3 mm、4 mm)、拋光時間(5 min、10 min、15 min、20 min)、頻率(100 Hz、300 Hz、500 Hz)等拋光參數，使用探針式表面粗糙度儀量測表面粗糙度並使用統計學假設檢定方法驗證拋光前後的表面粗糙度數值的顯著差異，結果顯示電極間隙2mm、4mm，拋光時間10min為最佳參數，但頻率未有最佳結果。再來使用萬能材料試驗機進行拉伸試驗實驗，3D列印機製作夾持鎳鈦線的Omega loop成形夾具，比較拋光前以及拋光後鎳鈦線的力學特性(彈性係數)是否有改變，並根據實驗量測原長度(L)及夾持後的長度(L1)計算變形量(△L)以及應變(ε)，最後以虎克定律計算出變形後的實際力量大小。結果顯示，直流電解拋光與交流電解拋光均可改善鎳鈦合金矯正線的表面粗糙度，且直流電解拋光不會改變鎳鈦矯正線的力學特性，但交流電解拋光因為氫脆化使鎳合金矯正線的力學特性嚴重退化，又根據虎克定律證實了鎳鈦合金矯正線在Omega loop的變形下對於第三類咬合不正的患者是有效的治療方式。
並列摘要
Nickel-Titanium Alloy has wide applications in the field of bio-medicinal, it is also made into orthodontic wires. Compare with stainless steel wire, nickel-titanium alloy wires Nitinol wire have better elasticity than stainless steel wire and can be adjusted with oral temperature. It can utilize the characteristics of shape memory to correct the teeth, and the instantaneous force is small to reduce the pain during the correction process. However, during the orthodontic treatment, there are still many dead corners of the teeth and orthodontics that are difficult to clean. Therefore, it is necessary to use surface treatment to improve the surface roughness of the orthodontic wires. The purpose is to make the patient easy to clean. According to the clinical results of orthodontics, it is pointed out that Omega loop is an effective treatment for patients with the third type of malocclusion. In this study used electrochemical polishing was used to improve the surface roughness of the nickel-titanium alloy orthodontic wires, a signal generator, power amplifier, and multi-function meter were used to measure the electrochemical reaction curve. After selecting the appropriate voltage range based on the measurement results by using DC/AC power supply for an electrolytic polishing experiment, fix electrolyte concentration (2 M), electrolyte temperature (50 °C) and voltage (2.1 V), change electrode gap (1 mm, 2 mm, 3 mm, 4 mm), polishing time (5 min, 10 min, 15 min, 20 min), frequency (100 Hz, 300 Hz, 500 Hz) and other polishing parameters, use probe-type surface roughness meter he probe of surface roughness meter to measure the surface roughness., Moreover, the statistical hypothesis verification method was used to verify the significant difference in surface roughness values surface roughness value before and after polishing significant difference. The results show that the electrode gap is 2mm and 4mm, and the polishing time is 10min as the best parameters, but the frequency , not the best parameters ,and then use the universal material testing machine to carry out the tensile test experiment, the 3D printer to make the Omega loop forming jig holding the nickel titanium wire, and compare whether the mechanical properties (elasticity) of the nickel titanium wire have changed before and after polishing, and calculate the amount of deformation (△L) and strain (ε) according to the original length (L) and the length after clamping (L1) measured by the experiment. Finally, the actual strength after deformation was calculated by Hooke’s law, proving which proves that the deformation given by the Ni-Ti correction wire is indeed faster than the normal correction time. The results show that both DC electrolytic polishing and AC electrolytic polishing can improve the surface roughness of Nitinol wire, and DC electrolytic polishing will not change the mechanical properties of Nitinol wire, but AC electropolishing makes nickel alloy straightened due to hydrogen embrittlement. The mechanical properties of the thread are severely degraded, and according to Hooke’s law, it is confirmed that the Nitinol correction wire is an effective treatment for the third type of malocclusion under the deformation of the Omega loop.