The retentive and stress distributing properties of split threaded endodontic dowels.

A threaded, parallel-sided endodontic dowel that has a longitudinal split was tested to determine its retention and stress distribution properties. Photoelastic stress analysis revealed high installation stresses unless the dowels were counterrotated. Axial loading created stresses at the threads, with elevated coronal and apical stresses. Even higher coronal stresses were recorded with inclined loads, and shorter dowels generated greater stresses than longer dowels. The retentive values were generally lower than those in comparable studies.