4种机动镍钛器械根管预备后对牙根抗折性的影响

Influence of 4 kinds of Ni-Ti instruments on the fracture resistance of root after canal preparation

目的:比较单支锉往复运动器械Reciproc、WaveOne与全序列旋转运动器械ProTaper和BLX根管预备后牙根抗折性的差异。方法:收集上、下颌离体前牙各50颗,分别随机分成5组(n=10)。分别用上述4种根管预备器械对4组牙进行根管预备,1组对照牙不进行根管预备。预备后将标本置于电子万能实验机上加压直至根折,记录折断瞬间所受的压力值(N)并进行统计学分析。结果:根管预备后实验组牙根的抗折力均低于对照组(P<0.05);Reciproc组与WaveOne组、ProTaper组与BLX组预备后牙根抗折力无统计学差异(P>0.05);Reciproc组和WaveOne组牙根抗折力高于ProTaper组和BLX组(P<0.05);当应用同种器械预备至同等号数时,上颌牙根的抗折力高于下颌牙根(P<0.05)。结论:往复运动预备系统器械根管预备后牙根的抗折性优于全序列旋转预备系统器械,上颌切牙预备后牙根的抗折性均高于下颌切牙。

Objective： To evaluate the fracture resistance of roots instrumented with Reciproc, WaveOne, ProTaper and BLX respectively. Methods： 50 extracted maxillary and 50 extracted mandibular anterior teeth were selected and randomly divided into 5 groups respectively（n = 10）. The teeth in the 4 experimental groups were instrumented by 4 the instruments respectively and the teeth in the control group were not treated. A vertical load was applied to the roots and the fracture load for each sample was recorded. The data were analyzed with SPSS 19.0 software. Results： After preparition the fracture load of the experimental groups was lower than that of the control （P 〈 0.05 ）, between the Reciproc and WaveOne groups （P 〉 0.05 ）, between ProTaper and BLX groups for maxi teeth （P 〉 0.05）, for mandibular teeth（P 〈0.05）. The fracture load of Reciproc and WaveOne was higher than that of ProTaper and BLX（P 〈 0.05 ）. After making same taper shape using same root canal instrument, the mandibular anterior teeth had lower fracture resistances than the maxillary anterior teeth （P 〈 0.05 ）. Conclusion： Single-file reciprocating systems groups may decrease less fracture resistance than fullsequence rotary systems, with or without instrumentation, maxillary anterior teeth have higher fracture resistance than mandibular anterior teeth.