Analysis of fracture resistance of endodontically treated teeth restored with different post and core system of variable diameters: an in vitro study.

Abstract

The restoration of endodontically treated teeth requires the fabrication of a post and core; to provide retention and support for the final crowns. The purpose of this study was to evaluate fracture resistance of endodontically treated teeth restored with prefabricated zirconia post (CP), milled zirconia post (MZ), pressable ceramic post (PC) and cast metal post (Ni-Cr) of 1.4 and 1.7mm diameter. 48 freshly extracted human maxillary central incisors were used for this study. The teeth were distributed in four groups of 12 teeth each. From each group, 6 teeth were selected for 1.4mm diameter post and rest of the 6 teeth, is selected for 1.7mm diameter post. All teeth were restored with metal crowns. Each specimen from the group was subjected to "load to fracture" in universal testing machine at 130° angle and the maximum load at failure was recorded. Statistically significant difference was found between the failure load of the groups studied. In group I (Ni-Cr)-1.4mm diameter post and core recorded a maximum fracture load of 534.83±1.28N and 1.7mm diameter post and core showed 294.33±1.02N. In group II (PC)-1.4mm diameter post and core recorded a maximum fracture load of 205.33±1.61N and 1.7mm post and core showed 375.00±1.57N. In group III (CP)-1.4mm diameter post and cores recorded a maximum fracture load of 313.00±0.73N and 1.7mm post and core showed 638.67±0.81N. In group IV (MZ)-1.4mm diameter post and cores recorded a maximum fracture load of 312.00±0.86N and 1.7mm post and core showed 415.00±0.89N. Prefabricated zirconia post (1.7mm) with pressable ceramic core (Cosmo post)-exhibited higher fracture resistance. Milled zirconia and prefabricated zirconia post-showed same value with 1.4mm diameter post. Pressable ceramic post and core showed satisfactory result with 1.7mm post, but showed lesser values with 1.4mm diameter post.