Effect of reapplication on pull-out bond strength of fibre post to root dentin: An in vitro study

Purpose: Post removal may be necessary for many reasons and is inevitable after the re-application of a dental post. The present study investigated the bond strength between root dentin and a re-applied fibre-reinforced composite (FRC) post by a pull-out test. Materials and methods: After root canal treatments of 30 extracted human maxillary canine teeth, post spaces were prepared (10 mm), and FRC posts (Hi-Rem Post; Overfibres, I(center dot)mola, Italy) were luted with self-adhesive resin cement. The samples were than randomly divided into test and control groups (n = 15 in each). The FRC posts were removed in the test group, and new posts were cemented. The pull-out test (1 mm/minute speed) was used to measure the bond strength. Failure types were determined using a stereomicroscope. Mann-Whitney U, chi-square and Fisher-Freeman-Halton exact tests were used for statistical analysis. Results: The bond strength values of the test (119.5 +/- 36.86 N) and control (115.55 +/- 55.44 N) groups did not differ significantly (p >.05). In terms of the percentage of failure types, there was a significant difference only in the test group between the mixed failure type and the other failure types (p <.05). Conclusions: The re-application of FRC post did not seem to affect the bond strength. The distribution of failure types was similar between the control and test groups.