以3.3釐米攻螺釘分析人造骨密度與切削阻抗之關係

Abstract

判斷植牙區骨質對於擬定人工牙根治療計畫有關鍵性的影響。但是時至今日，臨床上仍未有ㄧ安全有效而客觀的標準來判斷植牙區骨質的良劣。 本實驗的目的是試圖建立起切削阻力與人造骨塊密度的關連性，以供臨床上骨質判斷的參考。實驗方法是使用3.3釐米的攻螺釘在不同密度的人造骨塊上攻螺紋，將攻螺紋時的切削阻力記錄下來，分析切削阻力與人造骨密度的關係。均質骨塊密度共有五種，每種以三種不同的扭力設定20Ncm、30Ncm以及50Ncm攻螺紋。不同密度組合成的非均質骨塊共有六種，用以模擬臨床上不同的皮質骨與髓質骨組合，均以扭力設定50Ncm攻螺紋，每一樣本攻螺紋五次。 得到的切削阻力以作圖、平均以及估計斜率等方式得到每一種骨質切削阻力的特性。再用變異數分析、獨立樣本t-檢定以及複迴歸分析，檢定每一特性與骨質密度的關係。另外請四位手術醫師對不同骨質組合做測試，就醫師主觀的手感與切削阻力得到的結果作一比較。 結論是切削阻力與骨質密度的確有關聯性。骨質為均質或非均質可以由切削阻力平均-記錄點的圖形判斷出來。均質骨骨質可以由記錄到的切削阻力平均或是曲線上升斜率判斷，密度越大平均值越高，斜率越大。非均質骨的表層骨質可以藉由一般均質骨的方式來判斷，裏層骨質可以由曲線上升斜率來做推測。利用切削阻力的平均可以將均質骨以及非均質骨做一密度上的排列。以不同的手機對不同骨質做切削阻力的測試，需要校正。以機器所得到的切削阻力判斷骨質，要比手術醫師主觀的手感來的準確。臨床上以切削阻力判斷骨質應該是一個可行的方式。

Correctly classifying the bone quality of possible implantation area is of great importance in treatment planning.However, until very recently, a way to objectively, safely, and effeciently judging bone quality is still lacking. The purpose of this study is trying to figure out the correlation between cutting resistance and the density of artificial bone block for further clinicalutilization. By tapping with 3.3mm screw tap on different bone blocks with various denity, data of cutting resistance was collected for analyzation. Five homogeneous bone blocks were chosen, all was tapped with 20Ncm, 30Ncm, and 50Ncm of torque. Six different types of inhomogeneous bone blocks, which were combinations of different homogeneous bone blocks, were designed to mimic the various combinations of cancellous bone and cortical bone. All the six combination of bone blocks were tapped with 50Ncm of torque. Each of the sample was repeatedly tapped for five times. The data collected were analyzed by several stastistic methods to characterize different density of bone blocks by cutting resistance. Then ANOVA, t-test, and multiple regression analysis were utilized for further analysis. Four surgen were invited to tapping on bone-block-combinations, to verify subjective feeling from cutting resistance. The conclusion of this study is that, there really is correlation between cutting resistance and bone density. There is differences between curves of homogeneous and inhomogemeous density. In the curve of homogeneous test blocks, the higher the density, the higher the cutting resistance, as well as the slope of the curve rises. For inhomogeneous density, the outer bone is similar to general homogeneous blocks, and the inner bone can be speculated by the slope of the rising curve. Both homogeneous and inhomogeneous bone can be ranked by average cutting resistance. Verification is needed for different handpiece. Comparisons between subjective feeling of surgeons and objective cutting resistance records, the later is more accurate. Therefore, clinically, it might be able to verify various bone density with cutting resistance.