Journal of Dental Research, Vol 77, 1939-1947, Copyright © 1998 by International & American Associations for Dental Research Online Journals
Loading of a unilateral temporomandibular joint prosthesis: a three-dimensional mathematical study
J. P. van Loon, E. Otten, C. H. Falkenstrom, L. G. de Bont and G. J. Verkerke
TMJ Research Group, Department of Oral and Maxillofacial Surgery, University Hospital Groningen, The Netherlands.
The load on the prosthetic side and the influence of the design on the
remaining natural contralateral TMJ must be known before a unilateral
temporomandibular joint (TMJ) prosthesis can be developed. The aim of the
present study was to determine the maximum loading of the TMJ prosthetic
side and the natural contralateral TMJ and to investigate the influence of
the location of the center of rotation of the prosthesis on the maximum
loading. For this purpose, a mathematical model of the mandible with a
unilateral TMJ prosthesis with a fixed center of rotation (CR) was
developed. The location of the CR of the TMJ prosthesis was varied from the
middle of the natural mandibular condyle to 15 mm inferior to this
location. Although the maximum joint reaction forces changed as a result of
a unilateral TMJ prosthesis, the trend of the loading curves was similar to
that of an intact mandible. A unilateral TMJ prosthesis resulted in a 50%
higher loading of the prosthetic side, while the load on the natural
contralateral TMJ remained within normal limits. The maximum load on the
prosthetic side occurred during molar bites and could reach 100 N in the
cranial direction, 30 N in the ventral direction, and 25 N in the
medio-lateral direction. The location of the CR did not have a significant
influence on the loading of the TMJ prosthesis and the natural
contralateral TMJ.
