Influence of different cementation modalities on retention of fibre posts

Objectives: The retention of endodontic posts is believed to be a major factor in restoration survival. The aim of this study was to compare the retentive strength of fibre posts cemented with two different cements in combination with different pre-treatments. Methods: Forty caries free human maxillary incisors were selected for standardized size and quality, endodontically treated and coronally reduced to the cemento-enamel junction. During the experimental period the teeth were stored in saline. All specimens were randomly assigned to four experimental groups of ten samples each. In group A the fibre posts were sand-blasted and cemented with Panavia F. In group B the posts were cemented without sand-blasting. Group C received sand-blasted fibre-posts cemented with Ketac-Cem. In group D the posts were cemented without sand-blasting. Post holes were prepared according to manufacturers' instructions. The fibre posts (Mirafit Carbon) were then cemented with one of the two cements as recommended. Retentive strength was measured 24 hours after cementation using a universal testing machine. Results: The following mean retentive strengths in Newtons for the different groups were: group A: 448.4 N (+/- 105.9 N); group B: 395.7 N (+/- 99.9 N); group C: 210.9 N (+/- 66.5 N); group D: 176.8 N (+/- 67.2 N). Retentive strength in group A and B (Panavia F) was significantly increased compared to group C and D (Ketac-Cem) (p< 0.05, Tukey´s test). The influence of sand-blasting was for both cements not significant. Conclusions: The reconstruction of endodontically treated single rooted teeth with fibre posts showed acceptable retentive values for all cementation modalities used in this study. The values observed for the composite cement Panavia F were significantly higher compared to the conventional cement Ketac-Cem.