Cone beam computed tomography is a 3-dimensional high resolution imaging method. The purpose of this study was to compare the effects of 3 different NiTi rotary instruments used to prepare curved root canals on the fi...Cone beam computed tomography is a 3-dimensional high resolution imaging method. The purpose of this study was to compare the effects of 3 different NiTi rotary instruments used to prepare curved root canals on the final shape of the curved canals and total amount of root canal transportation by using cone-beam computed tomography. A total of 81 mesial root canals from 42 extracted human mandibular molars, with a curvature ranging from 15 to 45 degrees, were selected. Canals were randomly divided into 3 groups of 27 each. After preparation with Protaper, Revo-S and Hero Shaper, the amount of transportation and centering ability that occurred were assessed by using cone beam computed tomography. Utilizing preand post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Canals were metrically assessed for changes （surface area, changes in curvature and transportation） during canal preparation by using software SimPlant; instrument failures were also recorded. Mean total widths and outer and inner width measurements were determined on each central canal path and differences were statistically analyzed. The results showed that all instruments maintained the original canal curvature well with no significant differences between the different files （P=0.226）. During preparation there was failure of only one file （the protaper group）. In conclusion, under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. Areas of uninstrumented root canal wall were left in all regions using the various systems.展开更多
[Objectives]This study is to investigate the difference in the comprehensive effects of the two types of machine-used nickel-titanium(ni-ti)instruments in removing root canal filling materials to provide guidance for ...[Objectives]This study is to investigate the difference in the comprehensive effects of the two types of machine-used nickel-titanium(ni-ti)instruments in removing root canal filling materials to provide guidance for clinical applications.[Methods]We selected 60 single-tube premolars and randomly divided them into a P group(ProTaper ni-ti file group)and a K group(K3 ni-ti file group).The root canal was prepared according to the uniform standard crown cutting and manual k-file stepwise regression method.The root canal was fully filled and the X-ray film was taken.X-rays were taken again after re-treatment.The removal rate of the root filler material was obtained using Auto CAD 2000 image analysis software.[Results]We found no statistical difference in the clearance and total time of the two nickel-titanium devices in removing the gum filling material.Both the ProTaper ni-ti file and the K3 ni-ti file were able to remove most of the root canal filling during root canal retreatment.[Conclusions]There was no significant difference between the two devices in clinical applications.展开更多
文摘Cone beam computed tomography is a 3-dimensional high resolution imaging method. The purpose of this study was to compare the effects of 3 different NiTi rotary instruments used to prepare curved root canals on the final shape of the curved canals and total amount of root canal transportation by using cone-beam computed tomography. A total of 81 mesial root canals from 42 extracted human mandibular molars, with a curvature ranging from 15 to 45 degrees, were selected. Canals were randomly divided into 3 groups of 27 each. After preparation with Protaper, Revo-S and Hero Shaper, the amount of transportation and centering ability that occurred were assessed by using cone beam computed tomography. Utilizing preand post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Canals were metrically assessed for changes （surface area, changes in curvature and transportation） during canal preparation by using software SimPlant; instrument failures were also recorded. Mean total widths and outer and inner width measurements were determined on each central canal path and differences were statistically analyzed. The results showed that all instruments maintained the original canal curvature well with no significant differences between the different files （P=0.226）. During preparation there was failure of only one file （the protaper group）. In conclusion, under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. Areas of uninstrumented root canal wall were left in all regions using the various systems.
文摘[Objectives]This study is to investigate the difference in the comprehensive effects of the two types of machine-used nickel-titanium(ni-ti)instruments in removing root canal filling materials to provide guidance for clinical applications.[Methods]We selected 60 single-tube premolars and randomly divided them into a P group(ProTaper ni-ti file group)and a K group(K3 ni-ti file group).The root canal was prepared according to the uniform standard crown cutting and manual k-file stepwise regression method.The root canal was fully filled and the X-ray film was taken.X-rays were taken again after re-treatment.The removal rate of the root filler material was obtained using Auto CAD 2000 image analysis software.[Results]We found no statistical difference in the clearance and total time of the two nickel-titanium devices in removing the gum filling material.Both the ProTaper ni-ti file and the K3 ni-ti file were able to remove most of the root canal filling during root canal retreatment.[Conclusions]There was no significant difference between the two devices in clinical applications.
