The effect of 10% citric acid, 7% maleic acid & MTAD on intracanal smear layer removal - An sem study

Various organic acids,ultrasonic instruments,and lasers have been used to remove the smear layer from the surface of instrumented root canals. The purpose of this study was to determine the effectiveness of MTAD(a mixture of tetracycline isomer,an acid,and a detergent) as the final irrigant to remove the smear layer,compared with that of 10% Citric acid and 7% Maleic acid all of them following root canal irrigation with 5.25% Sodium hypochlorite (NaOCl). Forty eight extracted single rooted human teeth were randomly divided into 4 groups and instrumented with crown down technique using rotary nickel titanium files.5.25% sodium hypochlorite was used as the intracanal irrigant. The canals were treated with 5ml of one of the following solutions as final rinse:5.25% sodium hypochlorite,10% Citric acid,7% Maleic acid,MTAD. The presence or absence of smear layer on the surface of root canal walls at the coronal,middle and apical portion of each canal were examined under a scanning electron microscope. The results showed that MTAD is an effective final rinse solution for removing the smear layer in canals irrigated with sodium hypochlorite. When 10% Citric acid and 7% Maleic acid were used as a final rinse, the smear layer was removed from the middle and coronal thirds of canal preparations, but it was less effective in the apical third of the canals.