THERMAFIL RETREATMENT WITH AND WITHOUT CHLOROFORM SOLVENT

A previous study reported that retreatment of Thermafil-obturated cana ls resulted in significantly more remaining gutta-percha than retreatm ent of those obturated with laterally condensed gutta-percha. The purp ose of this study was to evaluate two retreatment methods in Thermafil -obturated canals. Thirty canals were cleaned and shaped. They were ob turated with Thermafil and sealer. One-half were retreated using chlor oform to aid in gutta-percha removal (group 1). The others were retrea ted without chloroform (group 2). The ease or difficulty of removing t he metal carrier was assessed during each retreatment. The teeth were split longitudinally; the canal area and remaining gutta-percha area w ere measured in the coronal, middle, and apical thirds. The results we re analyzed by analysis of variance. In each group, seven Thermafil de vices were easy to remove and eight were difficult. No significant dif ferences were found in comparing the two groups. However, when the fac tor of ease of removal was added there were significant differences. G roup 2 had significantly less gutta-percha in the apical third (5.9%) when the device was easily removed than when it was hard to remove (54 .2%). Group 2 canals were significantly cleaner in the apical third th an group 1 canals whether the device was difficult (38.3%) or easy to remove (42.5%). Adequacy of Thermafil retreatment may be related more to the ability to easily remove the carrier than to the technique of g utta-percha removal.