根管预备型号与充填温度对热牙胶充填根尖微渗漏的影响

Effect of size of preparation and temperature of obturation on apical leakage of root canal in vitro

目的评价根管预备型号与充填温度对充填后根管根尖微渗漏的影响。方法收集健康单根管前磨牙,Protaper镍钛系统行根管预备,根据完成锉型号分为F1～F6组（其中F6指0.60 mm,0.06锥度,是预备至F5后采用K锉逐步后退法预备而成）。组内根据充填温度分为高、低温组,各7颗。除根尖3 mm,牙体表面涂布2层指甲油。染色,制作透明牙后,牙科显微镜下测量根尖染料渗入深度,记录并统计分析。结果充填温度对根尖微渗漏的影响无统计学差异（P〉0.05）,根管预备型号（F1～F6）对根尖微渗漏的影响有统计学差异（P〈0.05）,充填温度与预备型号两因素间无交互效应（P〉0.05）。F2与其他各组根尖微渗漏差异均有统计学意义（P〈0.05）,F1与F3和F4组差异无统计学意义（P〉0.05）,与其他组间差异有统计学意义（P〈0.05）;F6与F1～F3组差异有统计学意义（P〈0.05）,与F4和F5组差异无统计学意义（P〉0.05）。结论热牙胶充填温度对根尖微渗漏无影响,而根管预备型号对根尖微渗漏有影响,预备型号为F2时,根尖微渗漏最小。

Objective To determine the effect of the size of preparation and the temperature of obturation on apical leakage of root canal in vitro. Methods A number of healthy premolars with single canal were collected. The root canals were prepared with Protaper nickel titanium instruments and divided into group F1 to F6 （ F6 meant 0.60 mm, tapered 0. 06, to which the root canals were prepared with K files by step back technique after prepared to F5） according to the finishing files. Teeth of every group were divided into low and high temperature subgroups according to the obturation temperature, with 7 teeth in each subgroup. The surfaces of the teeth were coated with 2 layers of nail polish except the apical 3 mm of the roots. All teeth were stained and made to transparent teeth, and the depth of dye from apices was measured and recorded under a dental microscope. The results were analyzed statistically. Results The effect of obturation temperature on apical microleakage had no significant difference （ P 〉 0.05 ）, but the effects of root canal preparation sizes （ F1 to F6） on apical microleakage had significant differences （P 〈 0.05 ）, and there was no interaction between 2 factors of obturation temperature and preparation sizes （ P 〉 0.05 ）. There was significant difference in apical microleakage between F2 and any other group （ P 〈 0. 05 ）, no significant difference between F1 and F3 or F4 （ P 〉 0. 05 ）, but there was significant difference between F1 and any other groups （P 〈 0. 05） ; there were significant differences of F6 with F1 to F3 groups （P 〈 0.05 ） and no significant difference of F6 with F4 or F5 group （P 〉 0.05 ）. Conclusion Obturation temperature has no effect on apical microleakage, and root canal preparation size has effect on apical microleakage. Apical microleakage will be minimum when the preparation size is F2.