Objectives: To compare the load fatigue resistance of three post and core systems.
Methods: Fifteen maxillary central incisors were divided into three groups of five each. Each sample tooth was prepared with a shoulder preparation having a 1.5 mm axial wall with the same dimension around the tooth. Each tooth was rebuilt with one of the following post and core restorations, Group1: cast gold post and core, Group II: 0.050 inch Parapost with composite core, and Group III: 0.050 inch fiber reinforced resin post with a composite core. The composite cores were bonded to dentin using a dentin bonding agent, and the cast post and cores and steel Paraposts were cemented with zinc phosphate cement. The fiber reinforced post was cemented with a dentin bonding agent and a resin cement. The crowns for all specimens were cast with an included notch where the fatigue load was applied. The independent variable measured was the number of load fatigue cycles required to fail the crown luting cement.
Results: The mean value for the cycles to failure for each group was: Group I 11,897 (4,080), Group II 24,384 (8,231) and Group III 50,696 (7,063). A one way ANOVA showed a significant difference between all groups (p < 0.001).
Conclusions: Using a fiber reinforced resin post and bonded composite core provided a significantly stronger crown retention under fatigue loading.