Effect of core materials on stress distribution of posts.

Severely damaged endodontically treated teeth require the use of a post and core for the retention of the restoration. The choice of material for a post and core and their stress-producing characteristics must be considered by the clinician. Two-dimensional photoelastic analysis of birefringent models was used to investigate the influence of different core materials on the stress distribution of nonthreaded cylindrical posts. Cast posts and cores and prefabricated posts with amalgam and composite resin cores were compared with posts without cores at installation and under two loading conditions. The findings indicate a significant difference between posts with and without cores. It appears that the stiffer core materials can shift the load from the apex to the coronal region.