Cleaning And Shaping Ability Of Manual K-Flexofile And Rotary ProTaper In Curved Root Canals In Vitro

The incidence of canal complication is higher in curved root canal than in straight one during the instrumentation. In this study, curved root canals were prepared with different instrumentation.The incidence of apical transportation,the instrumentation time and the change of working length of different groups were compared to evaluate the shaping ability of instruments. The data established for scoring the debris and smear layer on the canal walls were separately recorded and analysed to determine the cleaning effectiveness of instruments. 1 , Cleaning effectiveness and shaping ability of manual K-Flexofile in curved canal in vitroObjective: To compare the cleaning effectiveness and shaping ability of K-Flexofile and conventional stainless steel K-file in the curved root canals in extracted human teeth. Materials and methods:30 root canals with curvatures ranging between 10.3?and 24.7?were selected. According to the degree and radius of canal curvature, 30 molars were randomly assigned into two groups,each group was selected to be prepared with K-Flexofile or conventional K-file.Two groups were both prepared with double flared balanced forces technique.After each instrument,the canal was irrigated with 2ml 2.5%NaOCl and at the end of instrumentation the canals were flushed with 10ml 2.5%NaOCl and 10ml 17%EDTA alternately.Finally with 5ml distilled water.After splitting the canals longitudinally,the amout of debris and smear layer were quantified and the data were analysed separatly using Wilcoxon's test.By double exposure radiographic technique,the incidence of apicaltransportation was analysed with Fisher's exact test. The preparation time and the change ofworking length were analysed with Mann-Whitney U test. Results: There was significant difference in the apical part between two groups(P<0.05)when the debris and smear layer were graded;In the middle part,no significant difference were found(P>0.05);The incidence of apical transportation of K-Flexofile group was significantly lower than that of the K-file group (P<0.05).The preparation time and the change of working length between two groups showed no significant difference. Conclusion:The ability of K-Flexofile to clean and shape slight and moderate curved canal is superior to the conventional K-file.2 Cleaning effectiveness and shaping ability of rotary ProTaper in severely curved canal in extracted human teethObjective:To determine the cleaning and shaping ability of rotary ProTaper stainless steel hand K-Flexofile and rotary GT during the preparation of curved root canals in vitro.Materials and methods: 45 canals with curvatures ranging between 25.3?and 41.4?were divided into three groups.The groups were balanced according to the angel,the radius of canal curvature and the root length,canals were prepared by rotary ProTaper or GT using a crown-down technique or by hand K-Flexofile using double flared technique.The irrigation methods and evaluated index were all same as the part one. Results-.None of the ProTaper and K-Flexofile but 2 GT separated. For debris removal,ProTaper achived better results than GT (P<0.05) and K-Flexofile (P>.05); For smear layer removal,K-Flexofile achived better results than ProTaper and GT(in the middle part,P<0.01).ProTaper and GT both maintain the original curvature significantly better than K-Flexofile(P<0.05).For the time taken to prepare the canals, ProTaper was significantly shorter than GT(P<0.01)and K-Flexofile (P<0.0l). Conclusions :ProTaper allowed significantly better removal of debris than GT, K-Flexofile achived better removal of smear layer than ProTaper and GT; ProTaper and GT maintained the original curvature much better and took much shorter time to prepare canals than K-Flexofile; ProTaper took shorter time to shape canals than GT.