This examination gives the insightful knowledge of smearlayer abolition proceeding and capability of conventional irrigation protocoland continuous soft chelating irrigation protocol. Satisfactory irrigation,disinfection, and obturation are main principle of shaping. Accumulation ofsmear layer is noticed while shaping of canals which need to abolish with the helpof irrigating solution. Whole activity needed from an irrigant to reduce smearlayer from dentin wall cannot be obtain by any sole irrigating solution.
Therefore, combined application of multiple irrigating solutions is obligatory foroptimal abolition of smear layer (5).Whereas Chloroquick solution is mix ofHEBP (a soft chelating agent) and NaOCl which can disinfect root canal as wellas reduces smear layer. Highlight of such combination of NaOCl and Etridonicacid is that the NaOCl doesn’t surrender its biological, antibacterial andtissue dissolving properties (13, 14), whereas the reduction and elimination ofthe inorganic element is done with help of HEBP (11, 12). Outcome of this current research demonstrate eradicationof smear layer was more decisive in middle and coronal third in comparison toapical third.
These results are in accordance with study done by Abbott PV, Heijkoop PS et al. and numerous studies, which have proved in past thatan effective cleaning action in the middle and coronal third of the root canalseven with numerous irrigation solutions, different volume, and time (15, 16).In coronal and middle third areas where a larger canal diameter allows betterflow of solution and more time to be in contact with dentine wall which allows thesolution to remove smear layer comprehensively. (3,16).
Roleof surfactant has been discussed and reviewed by numerous authors, incurrentstudy SmearClear, SmearOFF and Chloroquick contains surfactant. Abou-Rass andPatonai confirmed that reduction of surface tension of endodontic solutionsimproved their flow into slender and narrow root canals (17). Therefore, an improvedpenetration into apical narrow part of canals can be seen with addition ofsurfactants to irrigation solution. In present study, SmearClear and SmearOFFdespite having additional surfactant doesn’t show the significant removal ofsmear layer in apical third when compared to control group of 17% EDTA, whichdoes not have any addition surfactant. This result is in accordance with theobservationsof Lui et al. (18) and also, other studies have shown that calciumchelating ability of solution is not improved by reducing the surface tensionof the solution. Presentstudy results disply that the continuous softchelating irrigation shows thesignificantly better removal of smear layer thanconventional irrigation protocol at apical third level when 18% HEBP was usedin combination with 5.
25% NaOCl (Chloroquick High). Where 9% HEBP incombination with 3% NaOCl (Chloroquick Low) did not show any significancedifference compared to conventional irrigation protocol groups. These resultscanbe attributed to chelating agent being more time in canal and also chelatingprocedure is seen while instrumentation, unlike conventional irrigationprotocol where removal of smear layer is done only once instrumentation iscompleted (19). Paque et al. demonstrated that the accumulation of hard tissuedebris in root canals when irrigated with amalgamation of NaOCl and HEBP was significantly less than irrigationwas performed with 2.5% NaOCl alone (20).
Another advantage of this combinationis that it has better tissue dissolution capacity by keeping the hypochlorite-hypochlorous acid equilibrium towards hypochlorite (21). This combination isaffective on inorganic as well as organic part of smear layer at same time. Resultof this study is in contrast to the recently published study by AbyKuruvilla et al. where 7%malic acid wasmore effective in removing smear layer as compared to 17% EDTA and 18%etidronic acid (22). This observation may be seen because 18% etidronic acid whichis soft chelating agent was merely used in a final rinse irrigation protocol andnot combined with sodium hypochlorite. There arevery few studies available on use of the continuous soft chelating agent forsmear layer removal.
Future study should be aimed towards effect of both this protocolon root canal walls. In present study, continuous soft chelating irrigationprotocol shows promising results.