Functional stress modification after high condylectomy surgery

Surgical removal of the head of the condyles inevitably leads to radical redistribution of loads applied to the mandible. The nature of this redistribution can have important implications on the surgical approach and subsequent reconstructive procedures. The purpose of this investigation was to visualize photoelastically the functionally delivered stresses after high condylectomy surgery. Three identical models of a dentate human mandible were constructed from a photoelastic material. One mandible simulated a unilateral and the other simulated a bilateral high condylectomy. The third mandible had both condyles intact and served as basis for comparisons. Silicone implants were placed on the sectioned condylar heads. The condyles, with the silicone implants, were fitted into simulated fossae and the mandibles were loaded unilaterally and bilaterally. The resulting stresses were observed and photographed in the field of a circular polariscope. Substantial differences in load-generated stresses were observed as a result of both unilateral and bilateral condylectomies, compared to the normal case. The most severe stress conditions occurred with the unilateral condylectomy, where stresses associated with torsion were most evident.