OBJECTIVEThe shear fracture strengths of carbon fiber post, IPS-Empress 2 all-ceramic post (without ZrO2 post), cast Ni-Cr alloy post, prefabricated zirconia ceramic post, human dentin and the shear bonding strengths of the first three kinds of post bonded in the human root canals were measured and compared, which are as the reference for dental clinic.

METHODSStandard cylindrical samples were made respectively in each group of carbon fiber post, IPS-Empress 2 all-ceramic post, cast Ni-Cr alloy post, prefabricated zirconia ceramic post, human dentin, three for each group. The shear fracture strengths of these samples were measured by universal testing machine (AUTOGRAPH DCS5000). Standard cylindrical samples were made respectively in each group of carbon fiber post, IPS-Empress 2 all-ceramic post (without ZrO2 post), cast Ni-Cr alloy post, five for each group. They were bonded in extracted human root canals that had been prepared to 3.0 mm length and 2.0 mm diameter with Glass ionomer cement (Japan Shofu). The shear bond strengths were measured by the same universal testing machine.

RESULTSThe shear fracture strengths of the carbon fiber post (199MPa), cast Ni-Cr alloy post (210MPa, shear bend strength) and prefabricated zirconia ceramic post (193MPa) were statistically higher than those of IPS-Empress 2 all-ceramic post (109MPa) and human dentin (100MPa). The shear fracture strength of the carbon fiber post was statistically similar to that of cast Ni-Cr alloy post and prefabricated zirconia ceramic post. There were no statistical differences between the shear bond strengths of carbon fiber post (2.4MPa) and cast Ni-Cr alloy post (3.8MPa). IPS-Empress 2 all-ceramic post broke before debonding (2.7, break value).

CONCLUSIONSCarbon fiber post, as well as cast Ni-Cr alloy post and prefabricated zirconia ceramic post, has a comparatively high shear fracture strength. The shear bond strengths of carbon fiber post is similar to cast Ni-Cr alloy post.