Effect of length post and remaining root tissue on fracture resistance of fibre posts relined with resin composite.

Abstract

To investigate the influence of post length and amount of remaining root tissue on the fracture resistance of roots restored with fibre posts relined with resin composite. Ninety upper canine teeth were divided into nine groups (n=10). The post spaces were prepared resulting in different lengths, as follows: group 2/3, preparations with lengths of 10mm; group 1/2, preparations with lengths of 7·5mm; and group 1/3, preparations with lengths of 5mm. Each group was divided into 3 subgroups according to amount of remaining root tooth tissue (2, 1mm or 0·5mm of thick root). Fibre posts relined with resin composite were cemented, and all teeth were restored with metal crowns. The samples were submitted to the fracture resistance test in a universal testing machine, at an angle of 135° and speed of 0·5mm min(-1) . Failure modes were observed and the data of fracture resistance were submitted to the anova and Tukey's (α=0·05). No statistically significant difference in fracture resistance was found among different post lengths (P>0·05). Remaining dentin thickness of 2 and 1mm did not differ statistically in fracture resistance (P>0·05), which was higher than of 0·5mm dentin thickness (P<0·05). A prevalence of repairable failure was observed in all groups. It can be concluded that the length of fibre post relined with resin composite did not influence fracture resistance, but thickness was an important factor for the restoration of endodontically treated teeth.