Effect of eugenol-based endodontic cement on the adhesion of intraradicular posts

The present study evaluated, in vitro, the influence of an eugenol-based endodontic sealer (EndoFill) on the adhesion of intra-radicular posts cemented with a resin-based cement (Enforce) ou a zinc phosphate cement. Twenty-four single-rooted maxillary canines were divided into 2 groups (n=12) and obturated with either gutta-percha points plus EndoFill or gutta-percha points alone (no cement). In each group, half of intracanal posts (n=6) were cemented with Enforce resin-based cement and half with zinc phosphate cement. Specimens were submitted to pull-out test in an Instron machine and tensile force was applied at a crosshead speed of 0.5 mm/min until post dislodgement. The maximum forces required for post removal was recorded (N) and means were submitted to statistical analysis by Kruskal-Wallis test (p<0.01). Posts cemented with zinc phosphate cement were significantly more retentive (353.4 N) than those cemented with Enforce (134.9 N) (p<0.01). Regarding the influence of the eugenol-based cement (EndoFill) on post retention, there was statistically significant difference (p<0.01) only between the groups cemented with Enforce, i.e., in the canals filled with EndoFill + guta-percha there was lower bond strength than in the canals filled with gutta-percha points alone (101.5 and 168.2 N, respectively). In conclusion, the zinc-phosphate-based cement showed greater post retention than the resin-based cement. The findings of this study suggest that the eugenol-containing sealer interfered with the adhesive properties of the resin-based cement.