RESIDUE OF GUTTA-PERCHA AND A GLASS-IONOMER CEMENT SEALER FOLLOWING ROOT-CANAL RETREATMENT

A previous report indicates that root canals obturated with a new glas s ionomer cement endodontic sealer (Ketac-Endo, Espe, Germany) and lat erally condensed gutta-percha can be retreated by ultrasonic instrumen tation. To address the possibility of Ketac-Endo being used without co ndensation of gutta-percha, the purpose of this study was to evaluate the efficacy of ultrasonic retreatment in canals obturated with single -cone gutta-percha and Ketac-Endo. Thirty root canals were prepared in a standardized way to ISO size 40 and obturated with gutta-percha and Ketac-Endo. Either a size 40 gutta-percha cone was used with and with out lateral condensation, or a size 2 5 single cone, without condensat ion. After 14 days, the canals were retreated using chloroform and ult rasonic instrumentation. The roots were split vertically, and the amou nt of residual debris on the canal walls was assessed by three examine rs using a dissecting microscope. Debris was recorded in the apical, m iddle and coronal canal levels according to a preset evaluation scale. The mean scores for each group were compared by ANOVA and Mann-Whitne y U-test, with a 5% level of significance. In the roots obturated with lateral condensation the amount of residual debris in the coronal and middle canal levels was lower than in the other two groups, whereas i n the apical level it was higher. Statistically, only the differences in the apical level were significant (P<0.03). It was concluded that u ltrasonic retreatment may be performed effectively in root canals obtu rated with single-cone gutta-percha and Ketac-Endo.