Evaluation of microleakage with and without smear layer : A bacterial penetration study.

Abstract

The effectiveness of root canal obturation after removal of smear layer by examining the rate of microbial leakage from the coronal direction was evaluated in this in -vitro study. Fifty freshly extracted human central incisors were decoronated and instrumented in a uniform manner. Following instrumentation, the root canals of 20 teeth were rinsed with 17% EDTA and 5.25% NaOCl to remove the smear layer before obturation. A second group of 20 teeth was flushed with NaOCl alone.The teeth in both the groups were obturated by lateral condensation of cold gutta percha using zinc oxide eugenol as sealer. The third group consisted of five teeth which served as positive control and the fourth group also having five teeth served as negative control. Each tooth was placed in a test tube containing sterile Trypticase Soy Broth (TSB). An inoculum of Proteus Vulgaris in Trypticase Soy Broth was placed in each coronal chamber at five days interval. Daily observation was made for bacterial growth in the apical reservoir for twenty one days. The frequency of bacterial penetration through teeth obturated with intact smear layer was significantly greater than that of teeth from which smear layer had been removed.