Effect of extracoronal versus intracoronal precision attachments on distal extension removable partial denture abutment supporting structures [finite element stress analysis]

ABSTRACT

The aim of this study was to assess by means of the finite element method the maximum principal stress generated in extracoronal and intracoronal precision attachments retaining bilateral distal extension removable partial denture. A realistic 3-dimensional, linear finite element model was used to investigate the biomechanics of the removable partial dentures retained by extracoronal and intracoronal precision attachments and their supporting structures under vertical occlusal loading. Stress distribution for each design was -examined with special attention being paid to the stress variations along the abutment teeth and the supporting bone. The results of this study revealed that tensile stresses were generated at the distocervical region of the second premolar incorporating the intracoronal attachment. Compressive stresses were detected at the distocervical region of the second premolar opposed with relative tensile stresses at the mesiocervical region of the first premolar in-corporating the extracoronal attachment. It was concluded from this study that extracoronal resilient attachment induced compressive stresses that would result in later bone resorption at the terminal abutment. Intracoronal attachments induced favorable stresses directed towards the long axis of the abutment