Comparison of the Photoelastic Stress for a Split‐Shank Threaded Post Versus a Threaded Post

PURPOSE: This study compared the stress distribution during insertion and after cementation for two prefabricated endodontic posts, (1) a split-shank threaded post, and (2) a threaded post with no split in the shank. MATERIALS AND METHODS: Three test blocks of photoelastic material were prepared with simulated endodontic canals for each group studied. Specimens were then photographed after insertion and cementation. RESULTS: Minimal stresses were observed for the post with a split (group 1) throughout the length of the shaft, whereas asymmetric patterns of stresses for the post without a split (group 2) were present. Stress distribution for the post without a split were concentrated more apically rather than coronally. CONCLUSIONS: The presence of a split reduces insertion and cementation stresses for this post system. The split also acts as a vent during the cementation of the post into the canal and minimizes stress concentration during cementation.