Evaluation of sealing properties of 70 degrees C thermoplasticized gutta-percha used as a retrograde root filling.

The efficacy of low temperature (70 degrees C) thermoplasticized gutta-percha used to seal root canals by the retrograde approach following apicectomy was assessed. A dye leakage technique was used, and gutta-percha was compared with amalgam. Two groups of different sized roots were apicected, and their root canals instrumented and filled conventionally with laterally condensed gutta-percha. Each group was randomly divided into four sub-groups; one was the control group in which no further treatment was carried out. In the other three groups the apical 3 mm of gutta-percha was removed, and the apical cavities filled as follows: group I with 70 degrees C thermoplasticized gutta-percha with sealer; group II with 70 degrees C thermoplasticized gutta-percha without sealer; group III with amalgam. The roots were rendered transparent by acid demineralization, and maximum dye penetration was measured. The results showed statistically significant ranking of leakage between the four sub-groups: 70 degrees C thermoplasticized gutta-percha with sealer less than 70 degrees C thermoplasticized gutta-percha without sealer less than amalgam less than control. The larger canals in all four sub-groups also exhibited significantly greater leakage than the smaller ones.