Survival rate and fracture strength of incisors restored with different post and core systems after exposure in the artificial mouth.

The survival rate and fracture resistance of 40 decapitated endodontically treated maxillary central incisors using four different post and core systems covered with all-ceramic copings was evaluated after exposure in the artificial mouth. Ten samples of the following post and core systems were investigated: high precious metal post (Permador) and core (Olympia) (A), zirconia post (Cerapost) with a pre-fabricated bonded ceramic core (Ceracap) (B), resin-ceramic post (experimental) with a pre-fabricated bonded ceramic core (Ceracap(R)) (C) and a zirconia post (Cerapost) with a custom made ceramic core (Cosmo Ingots) (D). The all-ceramic copings (Procera) were cemented using Panavia TC. The survival rates after 1 200 000 cycles in the artificial mouth are as follows: 90% (A), 80% (B), 60% (C) and 100% (D). The results of the means and standard deviations (s.d.) of the fracture resistance during static loading are: 1270 +/- 312.5 (A), 1494.5 +/- 333.5 (B), 1146.7 +/- 182.6 (C) and 463.3 +/- 46.2 (D). There are statistically significant differences between all groups with the exception of A and B, and A and C (Wilcoxon test). None of the zirconia posts with custom made ceramic cores covered with all-ceramic copings fractured during dynamic loading in the artificial mouth. The mean fracture strength during static loading was less favourable than that of groups A, B and C but above the clinical necessary level.