Evaluation of Sealers and Bonding Protocols on Fiber Post Retention

Objectives: To evaluate two endodontic sealers, two bonding systems and two application techniques on fiber post retention.

Methods: Human extracted canines (n=45) were cut to a standardized length of 16mm and divided equally into five groups. The root canals were cleaned, prepared and filled with gutta percha after which post spaces were prepared for #2 size D.T. Light fiber post (Bisco) using the manufacturer's protocol. Posts were cemented using Nexus3 dual cure resin cement (Kerr). Group A: Obturated with gutta-percha and eugenol sealer (Roth's 801), etched, rinsed and dried with paper points (conventional technique) and posts cemented using Optibond Solo Plus adhesive (Kerr). Group B: Same as group A except etched, rinsed and dried using the Deliver-Eze system (Ultradent). Group C: Same as group B except Optibond All-in-One adhesive (Kerr) was used. Group D: Same as group B except resin sealer (AH Plus, Dentsply) was used with the gutta percha filling. Group E: Same as group C except resin sealer was used. Post shear bond strengths were measured using pull-out test after 24 hours using a Universal Testing Apparatus at a crosshead speed of 1.0mm/min.

Results: The mean forces (Newtons) were 149.25, 212.88, 232.90, 242.66 and 265.37 for groups A to E respectively. Kruskal-Wallis rank test and Wilcoxon-Mann-Whitney rank sum test (p<0.05) revealed statistically significant lower bond strengths in group A; higher in group E as compared to group B; no difference between groups B, C and D. Both the post-cement and the cement-dentin bonds failed when using the conventional technique. Post-cement bond consistently failed before the cement-dentin bond when using the Deliver-Eze system.

Conclusions: Conventional technique resulted in lower bond strength when compared to the Deliver-Eze system. The bonding technique used during post cementation had greater impact on bond strength than the type of sealer or bonding system used.