Coronal dye penetration of the apical filling materials after post space preparation

Forty canals of palatal and distal roots of molars were cleaned and shaped with the use of a step-back technique. Thirty canals were obturated, 10 each with lateral, vertical, and thermafil techniques. Five root canals were obturated without a root canal sealer and served as positive controls. Another five root canals were obturated, and their coronal half was sealed with sticky wax and served as negative controls. The apical 5 to 6 mm of the filling materials were exposed to india ink for 48 hours. The depth of dye penetration was measured in all groups and statistically analyzed. The apical plugs in the thermafil group had the highest degree of coronal leakage. The ANOVA test showed a significant statistical difference between coronal dye leakage between this group and those found in canals filled by lateral or vertical condensation techniques. The results indicate that the apical filling materials obtained by lateral or vertical condensation leak less than those obtained by thermafil.