Variousformer studies have shown that the dentin wall was covered with smear layerafter mechanical shaping of the root canals with instrument (1,2). Disregardingof the controversy over retaining the smear layer it has been recognized that thesmear layer itself may be infected and may protect the bacteria within thedentinal tubules (3). Smear layer not only contains organic components but alsohave inorganic component in the form of dentin chips etc (1). The penetrationof intracanal disinfectants (4) and sealers into dentinal tubules wereprevented by smear layer, which affects the final seal of the root canalfilling (5, 6, 7). Irrigantsare paramount for complete debridement of the root canals with mechanical procedures(3). There is no single potent solution is appropriate for removing bothorganic and inorganic parts of the smear layer. To eliminate this smear layer mixof sodium hypochlorite (NaOCl) and strong chelating agent such as EDTA (Ethylenediaminetetraacetic acid) isrecommended (8). Crumpton et al.
proposedthat complete evacuation of smear layer can be achieved by 17% EDTA for 1minfollowed by 5.25% NaOCl (9,12). Till now there is no single solution which candisinfect the root canal system as well as remove the smear layer. On the otherhand the application of strong chelating agent like EDTA for more than minuteand 1ml of volume has been reported to be associated with dentinal erosion(10,11).SmearClear(Sybron Endo, Orange, CA) is a product introduced for eliminating the smearlayer. It contains 17% EDTA solution in conjunction with a cationic (Cetrimide)and an anionic surfactant.
SmearOFF (Vista Detal Products) is Proprietary EDTAand Chlrohexidine mix. It is prepared with combination of wetting agents andsurface modifiers for best outcomes. These solutions are used only as finalrinse.Etridonic acid which is soft chelating agent appearsto have a nominal effect on dentine walls and still cut down smear layer. Lottanti et al.showed that Etridonic acid (HEBP) can be used in combinationwith NaOCl without affecting its proteolytic or antimicrobial properties (13,14).
In contrast to EDTA, Etridonicacid is a weak decalcifying agent and hence cannot be used as a mere finalrinse there for it is suggested that HEBP to be mixed with NaOCl to be used asmore complete root canal irrigation solution. Chloroquick(innovationsendo, India) is a combination of NaOCl and HEBP. Chloroquick Highcontains 18% HEBP and 5.
25% NaOCl while Chloroquick Low contains 9% HEBP and 3%NaOCl both be mixed with surfactant tween 80 for complete root canal irrigationsolution. There for this study aims to compare the efficacy of continuous softchelating irrigation protocol with Chloroquick solutions to conventionalirrigation protocol on smear layer removal in coronal, middle, and apicalthirds of the instrumented root canals.