To compare ex vivo the penetration of three brands of gutta-percha cones, compacted under a constant force and heated to different temperatures, into artificial lateral canals.Methodology
Resin blocks with simulated main canals, each having two lateral canals (C at 6.5 and A at 13 mm from the surface of the resin block), were selected. A gutta-percha cone, either Mynol MF, Hygenic MF or GT Tulsa 0.04 was compacted into each main canal for 5 s using a wire rod with a diameter of 0.7 mm soldered to the bottom of a metal cylinder, with a force of 2.7 kg at controlled temperatures of 37, 42, 47, 52, 60 °C. The penetration of each brand of gutta-percha into 60 lateral canals (10 at each temperature) was measured using a stereomicroscope. Statistical analysis was performed using the ANOVA, the Scheffè test and the t-test.Results
None of the three brands of cones entered up to 0.1 mm within either lateral canal until a temperature of 47 °C was reached; at that temperature only Mynol cones (P ≤ 0.05) penetrated in four of 10 A-level canals (mean 0.13 ± 0.19 mm) and in all 10 C-level canals (mean 0.43 ± 0.12 mm).Results
The A-level lateral canals were penetrated at 52 °C by Mynol cones (mean 0.76 ± 0.34 mm) to a significantly greater distance (P ≤ 0.05) than Tulsa cones (mean 0.31 ± 0.12 mm) and Hygenic cones (mean 0.11 ± 0.08 mm). At 60 °C the Mynol cones (mean 1.93 ± 0.34 mm) penetrated significantly more (P ≤ 0.05) than the Tulsa cones (mean 0.86 ± 0.22 mm) and Hygenic cones (mean 0.67 ± 0.19 mm). The C-level lateral canals were penetrated at 52 °C by Mynol cones (mean 0.91 ± 0.29 mm) to a significantly greater distance (P ≤ 0.05) than Tulsa cones (mean 0.47 ± 0.16 mm) and Hygenic cones (mean 0.46 ± 0.15 mm), whilst no significant difference was found at 60 °C.Conclusions
When heated and compacted, the three gutta-percha cones penetrated the lateral canals to different degrees. They penetrated more than 0.43 mm into the lateral canals only at temperatures higher than 47 °C.