Abstract:

Objective

To evaluate the efficacy of R-Endo Nickel-Titanium rotary instruments in endodontic retreatment in vitro.

Methods

Extracted caries-free mature single-rooted permanent teeth were collected and divided into 6 groups according to the canal curvature. The teeth were obturated by gutta-percha and RealSeal resin obturation system， and retreated by Gates-Glidden drills. K files， HERO 642 Nickel-Titanium rotary instruments and R-Endo Nickel-Titanium rotary instruments， respectively. The total time of retreatment was recorded， extruded debris was collected and weighed. Moreover， the image of residual filling materials was outlined and measured by AutoCAD 2008 software.

Results

R-Endo system took more operating time than the other 2 methods （P=0.003）. And R-Endo system produced significantly less debris extrusion than by Gates-Glidden drill and K file （P=0.001）， but there was no significant difference between R-Endo an HERO 642 （P=0.239）. Moreover， the mean ratios of remaining fillings versus the area of groups retreated by R-Endo system was lower than other 2 groups， but of no statistically difference （P=0.157）. Besides， canals obturated by RealSeal resin obturation system took less operating time （P=0.001） and produced less debris extrusion （P=0.028） than by gutta-percha （P ＜0.05）.

Conclusions

R-Endo Nickel-Titanium rotary system is effective in endodontic retreatment. In comparison with hand instruments， it is more effective in canal wall cleanliness and less irritative to the periapical tissue. But the necessity for improvement on its safety should be recognized.

Key words: Endodontic retreatment, Nickel-Titanium, R-Endo rotary instruments