title: A comparison of Profile, Hero 642, and K3 instrumentation systems in teeth using digital imaging analysis. Comparison of removed dentin thickness with hand and rotary instruments Influence of the NiTi rotary system on the debridement quality of the root canal space. Comparison of curved canals preparations using profile, GT and Hero 642 rotary files.
abstract: OBJECTIVE To evaluate the changes in cross-sectional area morphology of curved canals after instrumentation with Profile((R ) ) , Hero 642((R ) ) , and K3((R ) ) using digital imaging analysis . Study design Thirty mesial m and ibular curved canals were used ( 25 - 40 degrees ) . The molars were embedded in resin and the roots were sectioned transversely at three levels : apical , middle , and coronal . The canals were r and omly distributed into 3 groups for instrumentation using Profile.04 and .06 , Hero 642 , and K3 . The pre- and postinstrumentation sections were digitized and areas corresponding to the canals were measured with image-processing software . RESULTS Hero  eliminated significantly more dentine than K3 and Profile in all 3 sections ( P < .01 , ANOVA test ) , with no differences observed between the latter 2 systems ( P > .05 , Student-Newman-Keuls test ) . All 3 systems yielded a rounded canal morphology in the coronal , middle , and apical thirds . CONCLUSION Hero rotary instruments produced more changes in cross-sectional area of the root canal INTRODUCTION : The aim of this study was to evaluate the amount of dentine removed after canal preparation using stainless steel ( SS ) h and instruments or rotary ProFile instruments . MATERIAL S AND METHODS : Thirty-six extracted human teeth with root canal curvatures less than 30º were embedded in clear polyester resin . The roots were cut horizontally at apical 2 , 4 and 7 mm . Dentin thickness was measured at each section and the sections were accurately reassembled using a muffle . Root canals were r and omly prepared by SS h and instruments or rotary ProFile instruments . Root sections were again separated , and the remaining dentin thickness was measured . Mann-Whitney U and t tests were performed for analytic comparison of the results . RESULTS : The thickness of removed dentin was significantly different between the two used methods ( P<0.05 ) . Significantly greater amounts of dentin was removed mesially in all sections in h and instrumentation group ( P<0.001 ) . CONCLUSION : ProFile rotary instrumentation prepares root canals with a greater conservation of tooth structure OBJECTIVE The present study was design ed to test the null hypothesis that there is no significant difference in debridement quality promoted by 3 nickel-titanium ( NiTi ) rotary systems . STUDY DESIGN Sixty-seven vital m and ibular molars that were prospect ively collected in vivo were used . The teeth were extracted and then pulp tissue fixed by 10 % formalin . The use of different NiTi rotary systems result ed in 3 experimental groups with 20 specimens each : G1 : Hero 642 ; G2 : K3 ; and G3 : ProTaper Universal . Afterward , the specimens were histologically prepared and serial 0.5 microm cross-sections were obtained every 0.2 mm from the 1 - 3 mm apical levels . The remaining pulp tissue was assessed using a morphometric approach . The cross-sectional area of each root canal and remaining pulp tissue were measured ( mcirom(2 ) ) . Thus , the percentages of remaining pulp tissue area were calculated for each root canal . RESULTS Overall , the pooled data obtained from all levels revealed a variable amount of remaining pulp tissue for all experimental groups . Remaining pulp tissue existed in every specimen . However , the Kruskal-Wallis H test was unable to show significant differences among the experimental groups ( P > .05 ) for the pooled data from all levels . CONCLUSIONS The present study did not find a significant difference in the quality of canal debridement between different NiTi rotary systems , because an adequate tapered shape is obtained This study compared preparations of curved canals , using Profile , GT file and Hero 642 rotary files .  A total of 30 mesiobuccal canals of extracted first and second m and ibular molars were used in this study . The teeth were embedded in resin and a pre-operative radiograph was taken . The specimens were then r and omly divided into three instrument groups . Pre- and post-instrumentation radiographic images were scanned and superimposed using the VISI CAD/CAM program . At nine horizontal sections at 1 mm increments from the apex , it calculated pre- and post-instrumentation cross sectional areas ( mm(2 ) ) and enlargements to the inner aspect and outer aspects ( mm ) . A Kruskal-Wallis test found no statistical difference among the groups in terms of total areas removed by each instrument ( P > 0.05 ) . It also found no significant difference in any group between the total of the inner and outer enlargements ( P > 0.05 ) . However the GT file removed significantly more material from the outer side of the canal than the inside at sections 3 - 5 , and the Hero removed significantly more material from the outer side at sections 7 - 9 ( P < 0.05 ) . All instruments produced preparations that maintained original canal curvatures
target: Therefore , the rotary NiTi Hero 642 and K3 files demonstrated comparable shaping abilities and maintenance of working length
background: The aim of the present study was to compare the root canal preparation ability of rotary nickel-titanium ( NiTi ) Hero 642 and K3 files in curved m and ibular or maxillary molars .