Fracture resistance of bone samples filled with fibre-reinforced composite posts: an ex vivo model

To evaluate the strengthening effect of two different types of fibre-reinforced composite (FRC) posts in an ex vivo experimental model.

Compact and hollow bone samples from bovine femurs were used as standardized samples. A total of 80 hollow samples were divided into two groups and filled either with a prefabricated FRC post or with individually adapted FRC posts. For each group, half of the samples were subjected to thermocycling (5-55 °C, 5000×). The remaining samples were kept for 24 h at 37 °C at 100% relative humidity. All samples were loaded diametrically until fracture. The null hypothesis tested was that the fracture resistance of standardized bone samples is not influenced by the type of FRC post, independently of the exposure to thermocycling. Results were evaluated by anova, and subsequent multiple comparisons were performed.

The samples filled with the individually adapted FRC posts were more resistant to fracture than the prefabricated ones (P < 0.001), but this difference was not apparent in the thermocycled groups. Detachment of the posts upon fracture was highest after thermocycling for both groups, amounting to 55% and 95% for the individual adapted posts and the prefabricated posts, respectively.

Initially, the samples filled with the individually adapted FRC posts were more resistant to fracture than those filled with the prefabricated ones. However, after ageing of the samples, both types of posts had similar strengthening effects.