Comparison of different techniques for obturating experimental internal resorptive cavities

Forty extracted maxillary central incisors were instrumented at the working length to a #50 file. The roots were sectioned transversely with a diamond disk at 7 mm from the anatomical apex. At the opening of the root canal of each section, hemi-circular cavities were drilled with a specially designe d bur. The corresponding root sections were cemented with glue, thus obtain ing root canals with Similar cavities that simulated internal resorptions. Teeth were embedded in plaster casts to facilitate their handling. The spec imens were randomly separated into four groups of 10. The following obturat ion techniques were evaluated: lateral compaction (group A), hybrid techniq ue (group B), Obtura II (group C), and Thermafil (group D). AH26 was used a s the sealer. After obturation, the plaster was removed and the teeth were radiographed in buccolingual and mesiodistal directions to evaluate the qua lity of the obturation at the IRC. The incisors were then cut with a scalpe l at the same level as the previous section, to examine, under a stereomicr oscope, the type of material that filled the IRC. Obtura II gave the best r esults and in most of the specimens obturated with this technique, the IRC were filled mainly with gutta-percha. Statistical analysis of the data indi cated that the differences between group C and the other groups were signif icant (P<0.05).