Retention of Adhesively Bonded Posts: Effect of Pretreatment of the Root Canal

Purpose: To evaluate the effect of three different root canal pretreatments on the retention of prefabricated titanium posts luted in the root canal with one of three resin cements. Materials and Methods: After removal of the clinical crowns of 216 extracted premolars, the root canals were prepared with the ParaPost system (length = 5 mm, diameter = 1.25 mm). The walls of the roots were subjected to either none (control) or one of three pretreatments: etching with citric acid, application of EDTA C, or mechanical roughening with a diamond-coated bur (n = 18 per group). CoJet-treated ParaPost XH posts were luted in the root canals with one of three resin cements: Panavia 2.0 F, Rely X Unicem, or ParaCem. Following water storage at 37°C for 7 days, retention was determined by extraction of the posts. Results: Mechanical roughening of root canal walls resulted in improved retention of posts, irrespective of the type of resin cement. Etching of root canal walls with citric acid resulted in improved retention only when Panavia 2.0 F was used. Depending on the resin cement, application of EDTA C had either no effect or a negative effect. Luting of posts with Panavia 2.0 F resulted in higher retention than did luting with Rely X Unicem or ParaCem. Conclusion: Mechanical roughening of the root canal walls with a diamond-coated bur was the most effective method to improve retention of posts. The use of Panavia 2.0 F resulted in higher retention than did the use of Rely X Unicem or ParaCem. Keywords: dowel, cementation, luting