The Effect of Metal Primer on the Retention of Casting Posts

Abstract

Statement of Problem: Retention of dental posts is an important factor for the longevity of final restorations in endodontically treated teeth. It can be influenced by such factors as the type of post, type of cement, the bond between the cement and dentin, and also cement with post surface. Purpose: The purpose of this study was to investigate the effect of a metal primer on the retention of casting posts luted with resin cement.Methods and Material: The crowns of 30 intact canine teeth were removed at CEJ with a disc. After root canal treatment, the post space was prepared in each specimen to a depth of 12mm. The posts were casted of non-precious alloy and sandblasted. The teeth were randomly divided into two groups (n=15). For both groups, casting posts were cemented into post spaces using panavia F2 according to the manufacturer’s instruction. The posts in group 1 were additionally pre-treated with Alloy Primer. The specimens were thermocycled and then debonded on an instron machine with a crosshead speed of 1 mm/min. The force required for dislodgement of the posts from the prepared spaces was recorded and the results were analyzed using t-test. Stereomicroscope was used to study the fracture interface in both groups.Results: The mean retention forces were 112.45±28.37 N for group 1 and 59.5±7.19 N for group 2. A statistically significant improvement in retention was found in the specimens in group 1 as compared with group 2 (p <0.05). Stereomicroscopy showed that failure at cement-post interface was 20% in group 1 and 60% in group 2Conclusion: Under the conditions of this study, casting posts pre-treated with metal primer provided a significantly greater retention.Key words: Metal primer, Post and core technique, Bond strength