THE ADAPTATION OF MECHANICALLY SOFTENED GUTTA-PERCHA TO THE CANAL WALLS IN THE PRESENCE OR ABSENCE OF SMEAR LAYER - A SCANNING ELECTRON-MICROSCOPIC STUDY

The objective of this study was to compare the adaptation of mechanica lly softened gutta-percha to the root canal wall in the presence and a bsence of smear layer, The root canals of 20 freshly extracted human m axillary incisors were cleaned and shaped, Prior to obturation, 10 roo t canals were irrigated with 20 mi of 50% citric acid followed by 20 m i of 5.25% sodium hypochlorite. All canals were obturated with mechani cal compaction of gutta-percha and AH-26 sealer, After 72h, each tooth was fractured in half, Scanning electron microscopy demonstrated that the sealer had formed a continuous layer in contact with the canal wa lls, becoming progressively thinner towards the apex, The sealer penet rated into the dentinal tubules along with projections of gutta-percha only in those teeth without smear layer.