Apical sealing ability of Thermafil following immediate and delayed post space preparations.

Sixty extracted human teeth were prepared in a step-back flare method. Forty-five were obturated with plastic Thermafil and 15 were filled with lateral condensation. The Thermafil filled teeth were divided into three groups consisting of no post preparation, immediate post preparation, or delayed post preparation. Post preparations were not performed (controls) on the laterally condensed specimens. After 10 days of exposure to methylene blue dye, the specimens were decalcified in nitric acid for 72 h. A volumetric analysis measuring absorbance was then performed on each specimen. Within the testing parameters, no significant differences in leakage were observed among the tested groups.