Rigidity and retention of carbon fibre versus stainless steel root canal posts.

Two of the main requirements of a root canal post are that it is rigid so as to resist flexing under functional load, and that it is well retained in the root. This study compared these properties in two different 1-mm diameter root canal posts--smooth carbon fibre posts (Endopost) and serrated stainless steel posts (Parapost). Ten posts of each type were tested for rigidity in a three-point bend test. Ten posts of each type were cemented with resin cement into the roots of endodontically treated, extracted teeth. The tensile force required to remove the posts was recorded. The Paraposts proved to be significantly more rigid under load (P < 0.001) and significantly more strongly retained in the tooth roots (P < 0.005). The Parapost appears to be a mechanically superior post for the restoration of root-filled teeth with narrow diameter root canals.