A SCANNING ELECTRON-MICROSCOPIC EVALUATION OF THE DEBRIDEMENT CAPABILITY OF SODIUM-HYPOCHLORITE AT DIFFERENT TEMPERATURES

The effect of raising the temperature of the irrigant solution on the smear layer was evaluated in the middle and apical third of 22 human u pper incisors, A 5% sodium hypochlorite (NaOCl) solution was used at 2 1 degrees C and at 50 degrees C. After hand instrumentation and treatm ent with the irrigant, teeth were fractured into halves and examined b y scanning electron microscopy, Characteristics of the smear layer in the two groups of specimens were compared. In the middle third, where NaOCl had been used at 50 degrees C, the smear layer was thinner and m ade of finer, less well-organized particles than where it had been use d at 21 degrees C. In the apical third, the smear layer was of almost the same thickness in the two groups of specimens, although the partic les were finer where the NaOCl had been used at 50 degrees C.