Effect of cast metal post configuration and tooth preparation design on fracture resistance of endodontically treated single rooted teeth with intact or mutilated coronal portion

ABSTRACT

The effect of cast metal post configuration and two different root face tooth preparation designs on fracture resistance of endodontically treated teeth with either intact or mutilated coronal portion were investigated on this study. Ninety one extracted mandibular second premolars were carefully selected to be used in the study. Four post designs were compared The serrated parallel sided, the smooth parallel sided, the tapered and the widely diverged posts. The posts and cores were cast from nickel chromium non precious alloy. Fixed length and diameter for all the root canal preparations were considered. Special drillers were used to standardize the root canal channels for every post design. Ready made plastic posts were used to standardize the post configuration for every design. Two different root face designs either beveled or non beveled were used for the mutilated teeth. All the samples were restored by full coverage cast metal crowns before testing. Specially designed copper cylindrical container were constructed to fix the samples roots in acrylic resin root block. A special rigid copper split matrix was constructed to help in construction of the core portions in a standardized manner. Compressive load was applied upon the samples using universal testing machine and the peak failure load and the mode of fracture was recorded for every sample. Statistical analysis of the results was done. All the tested designs except the widely diverged posts statically posses the same reinforcement effect upon intact or the mutilated endodontically treated single rooted teeth. The beveled root faced preparation increase the fracture resistance of the restored teeth compared with the non beveled tooth design. The widely diverged root canals was contraindicated as it produce weakening to the root portion