Comparative study of cutting efficiency of three instrumentation techniques in C-shaped canals

Abstract

Objective: To investigate the cutting efficiency of three instrumentation techniques in the C-shaped canals.Methods: Sixty extracted mandibular second molars,which contained C-shaped canals,were selected and cross-sectioned at 2,5,8 mm from the apex by using a muffle system as described by Bramante.The teeth were randomly divided into three groups,instrumented by three different techniques respectively.The digital images of the canal cross-sections pre-and post-instrumentation were taken to evaluate the amount of dentin removed,the position and the change of minimal canal wall.Perforation were recorded.Data were analyzed by using ANOVA.Results: The cutting efficiency on the weak wall of C-shaped canals by using three instrumentation techniques,was equivalent.The frequency of minimal walls appeared in lingual sides was much more than the others.There were three perforations in manual stainless steel K-file groups.Conclusion:The lingual wall of C-shaped canals was thinner commonly than other aspects,which should be paid more attention during canal instrumentation.

目的:評價3種常用根管預備方法預備C形根管時對根管壁薄弱區的切削程度,為臨床治療提供參考。方法:收集臨床拔除的具有C形根管的下頜第二恒磨牙60顆,應用改良Bramante技術,于距根尖2、5、8mm處將牙根橫斷。將樣本隨機分為3組,使用不同預備器械和方法進行預備。比較預備前后根管橫截面形態的數碼圖像,對3種不同方法的切削程度進行評價。評價指標包括牙本質切削面積、根管壁最小厚度出現部位及最小值變化和根管壁側穿發生情況。數據進行方差分析。結果:C形根管壁的薄弱區多出現在舌側,3種預備方法對C形根管壁薄弱區的切削沒有顯著差異。手用不銹鋼器械組中發生3例側穿。結論:在C形根管預備時應特別注意避免在頰舌側薄弱區的過度切削,以免發生穿孔。