The effect of variation in thermomechanical compaction techniques upon the quality of the apical seal

The purpose of the present study was to assess the effect of compactor design, alterations in rotational speed and modification to the basic technique of thermomechanical compaction on the quality of the apical seal produced by gutta-percha and sealer cement. The integrity of the apical seal achieved using two different configurations of compactor, rotational speeds of 8000 and 16,000 rev/minute and a hybrid technique which combined thermomechanical compaction with lateral condensation were compared with conventional lateral condensation. The same brand of gutta-percha and type of sealer were used throughout the investigation. A cleared tooth technique that allowed the three-dimensional assessment of Indian ink leakage was employed. Instrument fracture, a problem experienced in some other investigations, did not occur with either design of compactor used. Apical dye leakage was found to be a relatively frequent occurrence with each variation in obturation technique studied, including that of lateral condensation of cold gutta-percha and sealer. The results showed no significant difference in the mean degree of leakage for each of the groups or in the proportion of specimens that showed leakage (P greater than 0.1). The advantages of the hybrid method of root canal obturation were discussed.