不同型号不锈钢根管锉的循环疲劳性能

发布时间：2018-04-03 00:07

  本文选题：牙髓腔　切入点：不锈钢　出处：《中国组织工程研究》2017年26期

【摘要】：背景:根管器械折断是一种比较常见的口腔临床并发症,因此,研究不同型号不锈钢根管锉的循环疲劳性能,具有重要的临床意义。目的:探讨根管弯曲角度及根管器械横截面积变化对不锈钢根管器械循环疲劳性能的影响。方法:选取25#、30#、35#不锈钢K锉(长25 mm,锥度相同)各30支,每种型号随机分为3组,共9组,这9组分别置于弯曲角度为45°,60°,90°的自制人工模拟弯曲根管中,用16∶1减速手机(350 r/min)驱动不锈钢K锉。记录每组器械折断所需时间,将时间转换为转数,采用扫描电镜分析折断K锉断口的显微结构,收集循环疲劳性能实验中折断的器械,电子游标卡尺测量断尖长度。结果与结论:(1)在弯曲角度相同的情况下,随着器械横截面积的增大,器械折断所旋转的周期数明显减少(P0.05)。在型号相同、横截面积相同的情况下,随着根管弯曲角度的增加,器械折断所旋转的周期数明显减少(P0.05),器械的循环疲劳性能明显下降;(2)各组不锈钢锉的断口均为韧性断口,断口表面可见一些大小不等的圆形或椭圆形韧窝并存在微观空洞,韧窝间可见延晶断裂的脆性断面。随着根管弯曲角度增大,韧窝直径逐渐增大。在30#、35#不锈钢K锉断口形貌中,随模拟根管弯曲角度增加,脆性断面有逐渐增加的趋势;(3)对于25#不锈钢K型锉,随着根管弯曲角度的增加,器械折断的断尖长度逐渐减小,但变化不明显(P0.05)。对于#30,#35不锈钢K型锉,随着根管弯曲角度的增加,器械折断的断尖长度逐渐减小(P0.05),其中#35-60°组与#35-90°组变化呈下降趋势但变化不明显(P=0.095)。在根管弯曲角度相同的情况下,随着不锈钢器械型号的增加,器械折断的断尖长度变化没有规律;(4)结果表明,不锈钢K型根管锉在长度和锥度相同的条件下,横截面积越大根管器械的循环疲劳性能越低,器械越容易折断;相同型号的不锈钢K型锉,随着根管弯曲角度增大,折断位置越靠近根尖部位,即断尖长度越短,断针取出越困难。
[Abstract]:Background: fracture of root canal instruments is a common oral clinical complication. Therefore, it is of great clinical significance to study the cyclic fatigue properties of stainless steel root canal files of different models.Objective: to investigate the effects of root canal bending angle and cross-sectional area of root canal instruments on the cyclic fatigue properties of stainless steel root canal instruments.Methods: 30 stainless steel K files (25mm long, with the same taper) were selected for 25 #CU. Each model was randomly divided into 3 groups and 9 groups. The 9 groups were placed in a self-made artificial curved root canal with a bending angle of 45 掳, 60 掳and 90 掳, respectively.Drive stainless steel K file with 16:1 deceleration phone 350 r / min.The time required for fracture of each group of instruments was recorded and converted to rotational number. The microstructures of broken K files were analyzed by scanning electron microscope (SEM). The broken instruments in cyclic fatigue test were collected and the length of broken tip was measured by electronic Vernier caliper.Results and conclusion 1) under the same bending angle, with the increase of the cross section area of the apparatus, the number of rotated cycles decreased obviously.In the case of the same type and same cross-sectional area, with the increase of the root canal bending angle, the number of rotated cycles of the instrument breaking is significantly reduced, and the cyclic fatigue property of the apparatus is obviously decreased. (2) the fracture surfaces of the stainless steel files in each group are all ductile fractures.There are some round or elliptical dimples with different sizes on the surface of the fracture surface, and there are microvoids, and brittle sections of the ductile fracture can be seen between the dimples.The dimple diameter increases with the increase of root canal bending angle.In the fracture morphology of 30#CU 3 stainless steel K file, with the increase of simulated root canal bending angle, the brittle cross section gradually increased. For 25 # stainless steel K file, with the increase of root canal bending angle, the broken tip length of the instrument gradually decreased.But the change was not obvious (P 0.05).For the #30 / #35 stainless steel K file, with the increase of the root canal bending angle, the broken tip length of the apparatus decreased gradually, and the changes of #35-60 掳group and #35-90 掳group showed a downward trend, but the change was not obvious in #35-60 掳group and #35-90 掳group.When the root canal bending angle is the same, with the increase of stainless steel instrument type, the length of broken tip of the broken instrument does not change regularly (4) the result shows that the stainless steel K type root canal file has the same length and taper under the condition of the same length and taper.The larger the cross-sectional area, the lower the cyclic fatigue performance of the root canal instruments, and the easier the apparatus to break; the same type of stainless steel K file, with the increase of the root canal bending angle, the more close the fracture position is to the root tip, that is, the shorter the length of the broken tip,The more difficult it is to take out the broken needle.
【作者单位】： 天津医科大学口腔医院综合科;北京通州区新华医院口腔科;
【基金】：天津医科大学口腔医院科研基金(2013yky02)~~
【分类号】：R781.05
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本文编号：1702723