Efficacy of two different biomechanical root canal preparation techniques along with different final irrigating solutions in removing smear layer at the apical third -An invitro comparative study

Smear layer removal before obturating the root canals eliminates a bacteria-laden barrier and exposes the dentinal tubules. This allows root canal sealers to penetrate the canal walls, which significantly improves the hermetic seal, reduces microleakage, and minimizes the risk of root canal reinfection. The apical third of the root canal with its complex anatomy acts as a primary biological and mechanical barrier. Its three dimensional sealing is vital in preventing the ingress of microorganisms into the peri apical tissues.
This invitro study compares the efficacy of Hand and rotary root canal instrumentation techniques in removing the smear layer in the root canal -apical third when used with the following five different final irrigating solutions - 5.25% of sodium hypochlorite (NaOCl) , 17% EDTA, 6% morinda citrifolia (MC) extract, German chamomile extract (GCM) and 0.2% chitosan. The irrigation technique used was Passive Ultrasonic Irrigation.
The study concluded that, Hand instrumentations produced less amount of smear layer compared to rotary instrumentations. Chitosan exhibited the highest effectiveness followed by 17% EDTA, 6% GCM, 5.25% Na OCl and 6% MC, in removing the smear layer. German chamomile showed almost an equivalent ability to EDTA in removing the smear layer. 6% Morinda citrifolia showed least efficiency in removing smear layer when used with Rotary files .