EFFECT OF CALCIUM HYDROXIDE DRESSING ON SEAL OF PERMANENT ROOT FILLING

Low apical leakage along root fillings following an application of cal cium hydroxide was reported in a few methylene blue dye penetration st udies. It has been found recently that methylene blue is decolored by calcium hydroxide, indicating that the short penetration of methylene blue may not be due to a tight seal only. Of the 80 roots of human max illary central incisors used in this study 40 roots (group 1) received calcium hydroxide root canal dressing whereas another 40 roots (group 2) did not. All the roots were then obturated with gutta-percha and T ubli-Seal sealer. Leakage along 20 filled roots in each group was meas ured using a modified fluid transport model at 48 h, 2, 4, 8 and 16 we eks after obturation; whereas leakage of another 20 filled roots in ea ch group was measured using dye penetration with 1% methylene blue. Us ing the fluid transport model, no significant difference was found bet ween the two groups at any time interval (P=0.4847, 0.3875, 0.9490, 0. 4786? 0.9148 respectively after 48 h, 2, 4, 8 and 16 weeks); using the methylene blue penetration method, leakage in group 1 (with root cana l dressing) was significantly less than that in group 2 (without root canal dressing) (P=0.0374). The contradiction in results from the diff erent models indicated that problems existed with the models.