IATs improve intracanal cleanliness across a substantial portion of the canal , and therefore , their use is recommended throughout root canal preparation .
AIMS To establish whether irrigant activation techniques ( IATs ) result in greater intracanal smear layer and debris removal than conventional needle irrigation ( CNI ) .
A comparative study of the removal of smear layer by three endodontic irrigants and two types of laser.
AIM The effects of three endodontic irrigants and two types of laser on a smear layer created by h and instrumentation were evaluated in vitro in the middle and apical thirds of root canals . METHODOLOGY Sixty human mature extracted m and ibular premolar teeth with a single root canal and a closed apex were distributed r and omly into five groups of 12 teeth each . Whilst cleaning and shaping up to a size 60 master apical file with a step-back technique , the root canals were irrigated with 3 mL of 5.25 % NaOCL and 3 % H2O2 , alternately , between each file size . Group 1 ( G1 ) were control specimens that were irrigated with a final flush of 17 % EDTA . The teeth in group 2 ( G2 ) were irrigated with a final flush of 6 % phosphoric acid , and group 3 ( G3 ) with 6 % citric acid . In the specimens of group 4 ( G4 ) the root canals were irradiated with a carbon dioxide ( CO2 ) laser , and specimens of group 5 ( G5 ) were irradiated using an Er : YAG laser . The teeth were split longitudinally and prepared for examination by scanning electron microscopy . RESULTS Control specimens ( G1 ) showed clean root-canal walls with open dentinal tubules in the middle one-third , but in some specimens thick smear layer was observed in the apical one-third . Specimens irrigated with a final flush of 6 % phosphoric acid ( G2 ) or 6 % citric acid ( G3 ) were cleaner than with 17 % EDTA , showing very clean root canal surfaces in the middle one-third but in the apical one-third the smear layer was not completely removed , especially at the openings of the dentinal tubules . The specimens irradiated with the CO2 laser ( G4 ) showed clean root-canal walls with the smear layer absent , charred , melted , recrystallized and glazed in both middle and apical thirds . The root-canal walls of the specimens irradiated with the Er : YAG laser ( G5 ) revealed an absent smear layer with open dentinal tubules in the middle and apical thirds . Statistical analysis showed no significant difference in the cleanliness of root-canal wall between G1 and G2 , and G1 and G3 . However , there were statistically significant differences ( P < 0.01 ) between G1 and G4 , and G1 and G5 in the cleanliness of the middle and apical one-thirds of the root canals . CONCLUSIONS Irrigation with 17 % EDTA , 6 % phosphoric acid and 6 % citric acid did not remove all the smear layer from the root-canal system . In addition , these acidic solutions demineralized the interbular dentine around tabular openings , which became enlarged . The CO2 laser was useful in removing and melting the smear layer on the instrumented root-canal walls and the Er : YAG laser was the most effective in removing the smear layer from the root-canal wall
IATs improve intracanal cleanliness across a substantial portion of the canal , and therefore , their use is recommended throughout root canal preparation .
AIMS To establish whether irrigant activation techniques ( IATs ) result in greater intracanal smear layer and debris removal than conventional needle irrigation ( CNI ) .