Sealing ability of thermoplasticized gutta-percha fill techniques as assessed by a new method of determining apical...

One hundred fifty-nine extracted single-rooted maxillary human teeth were instrumented and randomly divided into nine groups of 17 teeth each and 6 control teeth. Experimental groups were obturated with Thermafil, Obtura II, Ultrafil Regular Set gutta-percha, and Ultrafil Firm Set gutta-percha, each with or without root canal sealer. A control group was obturated using the lateral condensation technique and sealer. Teeth were immersed in a resorcinol-formaldehyde resin for 5 days at 4 degrees C, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were then sectioned horizontally at 1.5, 2.5, and 3.5 mm from the anatomical apex, and examined under a stereomicroscope at x25 magnification. The resin filled the spaces in the gap between the canal wall and the gutta-percha and this was measured at each of the three levels. The ratio of the area of the resin to the total area of the canal was obtained as the mean leakage area. The results showed no significant difference in the mean leakage area at the same level for the different obturation materials. However, the leakage was significantly less for all materials when root canal sealer was used.