牙髓病治療之鎳鈦合金銼針扭轉分析

Abstract

鎳鈦合金銼針是醫治牙髓病時，首要與牙齒接觸的器械，其功能為鑿孔根管與清除遭受感染化膿的牙髓。本研究的目標就是探討鎳鈦合金銼針的機械性質，經過實驗量測與評估，歸納出銼針實際應用的扭轉受力範圍，以便日後設計或牙醫師在使用根管治療機時，可以調控扭力大小值，降低銼針毀損的可能性。 本研究藉著理論推導、電腦模擬、和實驗量測三種途徑，探討鎳鈦合金銼針的特性，其結果互相吻合貼近，實驗結果可信度高。由於銼針是非常細微且螺旋狀的切削器械，常常在治療過程中會導致斷裂，若斷裂於根管內部，將可能導致發炎的情況。為此探討銼針的機械性質，並且執行實驗，量測銼針的扭轉力矩與變形角度的關係，與量測銼針尖端受力與彎曲角度的關係。鎳鈦合金銼針之非線性扭轉變形實驗結果的分布與線性解析解的趨勢貼近，基於該結果，未來在進行根管治療時可參考線性解析解，同時考量使用上的安全，將調控扭矩的數值設定為2/3倍解析解的數值，以避免扭矩過高造成銼針斷裂的發生。

Nickel-titanium files are the primary tools when people undergo root canal treatment for teeth. Its function is to bore the root canal and clean infected pulp. This study is to investigate the mechanical properties of nickel-titanium files and provide some experimental data for designers or dentists that can regulate torque value conveniently. This research explores the characteristics of nickel-titanium files by theoretical solutions, computer simulation, and experimental measurement. These results coincide with each other so the experimental data is trustworthiness. Therefore this research aims to investigate file mechanical properties. This study investigates the relationship between torsional torque and torsional deformation by experiments. Also, this study investigates the relationship between the measured force at the file tip and bending angle in experiments. When nickel-titanium files are subject to torsional moment, the results of nonlinear deformation are close to the tendency of linear analytic solutions. Based on this reason and for safety reason of avoiding file failure, dentists can refer to the two-thirds analytic values as torque regulation for endodontic treatments.