title: Comparison of the photoelastic stress for a split-shank threaded post versus a threaded post.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.forename: B I
authors.initials: BI
authors.lastname: Cohen
authors.forename: B L
authors.initials: BL
authors.lastname: Musikant
authors.forename: A S
authors.initials: AS
authors.lastname: Deutsch
mesh_terms: D001718:Birefringence; D002484:Cementation; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D011176:Post and Core Technique / Q000295:instrumentation*; D015036:Zinc Phosphate Cement
chemical_list: D015036:Zinc Phosphate Cement