Variousformer studies have shown that the dentin wall was covered with smear layerafter mechanical shaping of the root canals with instrumentation (1,2). Disregardingof the controversy over preserving 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 successful debridement of the root canals with mechanical procedures(3). There is no single effective solution available for removing both organicand inorganic parts of the smear layer. To eliminate this smear layer mix ofsodium hypochlorite (NaOCl) and strong chelating agent such as Ethylenediaminetetraaceticacid (EDTA)is recommended (8).
It has been suggested by Crumpton et al that complete evacuationof smear layer can be achieved by 17% EDTA for 1min followed by 5.25% NaOCl (9,12).Till now there is no single solution which can disinfect the root canal systemas well as remove the smear layer. On the other hand the application of strongchelating agent like EDTA for more than minute and 1ml of volume has beenreported 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 yet can still reduce smear layer Lottanti et al. 2009. Etridonicacid(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.