本文選題：預(yù)加載應(yīng)力 + 疲勞折斷��； 參考：《口腔醫(yī)學(xué)研究》2017年08期

【摘要】：目的:比較K3XF和K3經(jīng)過預(yù)加載疲勞應(yīng)力后的表面形態(tài)和疲勞折斷性能。方法:25 mm長(zhǎng)、25#/0.06錐度的K3XF和K3各48支,隨機(jī)分為4組(n=12),組1不做預(yù)加載。組2~組4分別使用60°彎曲角度、3.5mm彎曲半徑的模擬金屬根管預(yù)加載疲勞應(yīng)力5s、10s、20s。每組隨機(jī)選取2支銼在SEM下觀察表面形態(tài),其余10支銼使用上述模擬根管進(jìn)行疲勞折斷實(shí)驗(yàn)。記錄疲勞折斷時(shí)間,計(jì)算疲勞折斷圈數(shù);測(cè)量折斷段長(zhǎng)度,并對(duì)折斷斷口進(jìn)行SEM觀察。SAS 9.3軟件進(jìn)行雙因素的方差分析,顯著性水平0.05。結(jié)果:SEM見兩種根管銼彎曲最大處的切割刃明顯磨損、出現(xiàn)大量裂紋、邊緣不整齊。K3XF表面缺陷明顯少于K3。K3XF預(yù)加載疲勞應(yīng)力20s后的疲勞折斷圈數(shù)從新銼的(210±59)降低為(156±37),差異有顯著性(P0.05)。K3預(yù)加載疲勞應(yīng)力5s、10s、20s后的疲勞折斷圈數(shù)從新銼的(145±38)分別降低為(110±27)、(101±31)和(62±31),5s和10s組無顯著差異,其余兩兩之間差異有顯著性(P0.05)。結(jié)論:K3XF對(duì)預(yù)加載疲勞應(yīng)力的抵抗性優(yōu)于K3。
[Abstract]:Aim: to compare the surface morphology and fatigue fracture properties of K3XF and K3 after pre-loading fatigue stress. Methods 48 K3XF and K3 with the taper of 25 #10 / 0.06 were randomly divided into 4 groups, without preloading in group 1. Group 2 ~ 4 used simulated metal root canal pre-loading fatigue stress of 5s10 ~ 10s ~ 20s with 60 擄bending angle and 3.5 mm bending radius respectively. In each group, two files were randomly selected to observe the surface morphology under SEM, and the other 10 files were tested for fatigue fracture using the simulated root canal mentioned above. The fatigue fracture time was recorded, the number of fatigue fracture circles was calculated, the length of fracture segment was measured, and the SEM observation. SAS9.3 software was used to analyze the variance of two factors. The significant level was 0.05. The results showed that the cutting edge of the two kinds of root canal file had obvious wear and tear and a large number of cracks appeared in the maximum bend of the root canal file. The number of fatigue broken rings decreased from 210 鹵59 to 156 鹵37 when the surface defects of K3XF were obviously less than those of K3.K3XF preloaded fatigue stress 20s. The difference was significant after pre-loading fatigue stress of 5s ~ 10s ~ 20 s. The number of fatigue broken rings was 145 鹵38 from the new file. There was no significant difference between 10 s and 10 s groups. There was significant difference between the other two groups (P 0.05). Conclusion the resistance to preloading fatigue stress of K3XF is better than that of K3XF.
【作者單位】： 首都醫(yī)科大學(xué)口腔醫(yī)學(xué)院牙體牙髓科;北京大學(xué)口腔醫(yī)院第二門診部;
【基金】：國家自然科學(xué)基金項(xiàng)目(編號(hào):81200826)
【分類號(hào)】：R781.05
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本文編號(hào)：1955175