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ePaper created 2016-03-31, 16:35:38 | version 1.38.0
| review irrigation 16 roots1 2016 Irrigation dynamics in root canal therapy Author: Prof. Anil Kishen, Canada Irrigation dynamics deals with the pattern of irrigantflow,penetration,exchangeandtheforces produced within the root canal space. Current modes of endodontic irrigation include the tradi- tional syringe needle irrigation or physical meth- ods, such as apical negative-pressure irrigation or sonic/ultrasonically assisted irrigation. Since the nature of irrigation influences the flow of irrigant up to the working length (WL) and interaction of irrigant with the canal wall, it is mandatory to un- derstand the irrigation dynamics associated with various irrigation techniques. Endodontic irrigants are liquid antimicrobials used to disinfect microbial biofilms within the root canal. The process of delivery of endodontic irrig- ants within the root canal is called irrigation. The overall objectives of root canal irrigation are to in- activate bacterial biofilms, inactivate endotoxins, and dissolve tissue remnants and the smear layer (chemical effects) in the root canals, as well as to allow the flow of irrigant entirely through the root canal system, in order to detach the biofilm struc- tures and loosen and flush out the debris from the root canals (physical effects). While the chemical effectiveness will be influenced by the concentra- tionoftheantimicrobialandthedurationofaction, the physical effectiveness will depend upon the ability of irrigation to generate optimum streaming forces within the entire root canal system. Thefinalefficiencyofendodonticdisinfectionwill depend upon both chemical and physical effective- ness.1–3 It is important to realise that even the most powerful irrigant will be of no use if it cannot pene- trate the apical portion of the root canal, interact with the root canal wall and exchange frequently within the root canal system.1 Figs.1a–d:Velocitymagnitudeofirriga- tionshowingtheextentofdeadzone. Withtheopen-endedneedletip(a),the velocityprogressivelydecreased 1.5 mmapicalfromthetip.Withthe side-ventedneedletip(b),therewasa muchlowervelocitythanwiththeopen- endedtip,anditextendedonly0.5 mm. Withtheapicalnegative-pressure irrigation(c),therewasaconstant velocityslightlyhigherthantheside- ventedneedleirrigationthatwas constantastheirrigantmovedcoronally. Theultrasonicallyassistedirrigation(d) showedthehighestmagnitudeof velocity,constanttoatleast3mm coronaltothetipplacement.35 Fig.1c Fig.1a Fig.1d Fig.1b