Apical leakage in maxillary type IV premolars with three different endodontic treatments.

The aim of this study was to evaluate the sealing ability in orthogradely filled, apicoectomised and retrogradely filled maxillary premolars with two canals and two separate apical foramina. The root canals of 51 extracted maxillary premolars of type IV were uniformly shaped and filled by means of lateral condensation and subsequently randomly divided into three groups of 17 teeth each. The teeth of groups II and III received an apicoectomy. In group III an additional retrograde seal (Ketac Fil) was applied. Group I served as control. All specimens were immersed in a methylene blue solution for 24 h. The teeth were cross-sectioned and the maximal dye-penetration was measured. The significantly least dye-penetration was observed in group II (apicoectomy only), followed by group I and group III. The differences among all groups were statistically significant (p<0.05). Most of the retrograde restorations in group III revealed circular colouration around the retrograde fillings extending to the gutta percha. Although the teeth of group II revealed the least dye-penetration, an apicoectomy cannot be favoured against an endodontic retreatment in maxillary premolars of type IV. The application of retrograde fillings using Ketac Fil must be considered critically.