EVALUATION OF PENETRATION DEPTH OF SODIUM HYPOCHLORITE INTO DENTINAL TUBULES AFTER PASSIVE ULTRASONIC IRRIGATION COMPARED TO ER;YAG LASER ACTIVATION. AN IN-VITRO STUDY

Abstract

Objectives: The aim of this study was to compare penetration depth ofsodium hypochlorite into dentinal tubules after passive ultrasonic agitationand ER; YAG activation.Materials and methods:Twenty-four single rooted human maturemandibular premolars were decoronated and accessed. After locating theapex and determining the working length, preparation of root canal was doneup to #35 file using Mtwo system and with 5.25%NaOCl irrigation. Teethwere then sealed apically with wax and submerged in a crystal violet dye for48 hours to stain dentin. NaOCl Irrigation was activated with eitherUltrasonic or ER;YAG laser. Specimens were sectioned longitudinally anddepth of bleached zone was evaluated under a stereomicroscope 40X.Results:Penetration depth was significantly higher in overall root canal inultrasonic group than ER;YAG laser group (P=.000). In ER;YAG Lasergroup, the highest penetration depth was in the coronal third followed bymiddle and apical, with significant difference between apical third and bothmiddle and coronal thirds (P=.009, .003 respectively), and no significantdifference between middle and coronal thirds (P=.083).Highest penetrationdepth was seen in the middle third, followed by coronal and apical,withnosignificant difference in penetration depth between the three sections of theroot canal activated with Ultrasonic (P=.664).Conclusion: ultrasonic activation can lead to more NaOCl penetration intodentinal tubules than activation with ER;YAG.