Conclusions The results of this systematic review suggested that NiTi rotary instruments were associated with lower canal transportation and apical extrusion when compared to SST h and files , whereas both groups had similar outcomes in terms of success of therapy , amount of residual bacteria , and cleansing ability after treatment .
Introduction This systematic review evaluated the effectiveness of  nickel‐titanium ( NiTi ) rotary files compared to stainless‐steel ( SST ) h and files .
Ex vivo study on root canal instrumentation of two rotary nickel-titanium systems in comparison to stainless steel hand instruments.
AIM To investigate instrumentation time , working safety and the shaping ability of two rotary nickel-titanium ( NiTi ) systems ( Alpha System and ProTaper Universal ) in comparison to stainless steel h and instruments . METHODOLOGY A total of 45 mesial root canals of extracted human m and ibular molars were selected . On the basis of the degree of curvature the matched teeth were allocated r and omly into three groups of 15 teeth each . In group 1 root canals were prepared to size 30 using a st and ardized manual preparation technique ; in group 2 and 3 rotary NiTi instruments were used following the manufacturers ' instructions . Instrumentation time and procedural errors were recorded . With the aid of pre- and postoperative radiographs , apical straightening of the canal curvature was determined . Photographs of the coronal , middle and apical cross-sections of the pre- and postoperative canals were taken , and superimposed using a st and ard software . Based on these composite images the portion of uninstrumented canal walls was evaluated . RESULTS Active instrumentation time of the  Alpha System  was significantly reduced compared with ProTaper Universal and h and instrumentation ( P < 0.05 ; anova ) . No instrument fractures occurred in any of the groups . The Alpha System revealed significantly less apical straightening compared with the other instruments ( P < 0.05 ; Mann-Whitney U test ) . In the apical cross-sections Alpha System result ed in significantly less uninstrumented canal walls compared with stainless steel files ( P < 0.05 ; chi-squared test ) . CONCLUSION Despite the demonstrated differences between the systems , an apical straightening effect could not be prevented ; areas of uninstrumented root canal wall were left in all regions using the various systems
Conclusions The results of this systematic review suggested that NiTi rotary instruments were associated with lower canal transportation and apical extrusion when compared to SST h and files , whereas both groups had similar outcomes in terms of success of therapy , amount of residual bacteria , and cleansing ability after treatment .
Introduction This systematic review evaluated the effectiveness of  nickel‐titanium ( NiTi ) rotary files compared to stainless‐steel ( SST ) h and files .