Root reinforcement with a resin-bonded preformed post.
PURPOSE: This study evaluated the ability of resin-bonded posts to reinforce teeth that are structurally weak in the cervical area against fracture. MATERIAL AND METHODS: Forty canine roots were endodontically treated and randomly distributed into four groups of 10. Parallel-sided preformed posts were cemented into the roots of these teeth after their crowns were removed. The cervical third of the canals were flared to simulate teeth weakened in this area as a result of caries or endodontic therapy. Three resin cements and a zine-phosphate cement, which was used as the control, were used to secure the posts into the roots. Cemented posts were loaded in an Instron testing machine with a gradually increasing force at a 60-degree angle to the long axis of the root until the root fractured. RESULTS: Roots in which the posts were cemented with Panavia were significantly more resistant to fracture than those where zinc phosphate was used (p < 0.05). Because of the inability to determine exactly the point of failure of the zinc-phosphate cement, no statistically significant difference was found when compared with the other two resin cements (ANOVA and Student-Newman-Keuls test).