Mandibular height asymmetry following experimentally induced temporomandibular joint disk displacement in rabbits.

OBJECTIVE

The purpose of this study was to test the hypothesis that nonreducing disk displacement of the temporomandibular joint causes mandibular asymmetry.

STUDY DESIGN

Unilateral anterior temporomandibular joint disk displacement with intact posterior disk attachment was surgically created in the right joints of seven growing rabbits. In each of seven sham animals, the right temporomandibular joint was surgically opened without any disk manipulation. Seven animals served as references. For identification of ramal growth and inferior growth at the mandibular base, tantalum implants were inserted into the mandibular body. Lateral cephalograms were exposed repeatedly throughout the 3-month investigation period. Kruskal-Wallis one-way analysis of variance was used to compare the groups.

RESULTS

Compared with the sham and reference groups, the experimental group exhibited a deviant growth pattern, with inferiorly directed growth along the mandibular base and in the gonial area. The ramal height was significantly shorter on the side with disk displacement. No significant side difference was present in the sham and reference groups.

CONCLUSIONS

Disk displacement can cause mandibular asymmetry in growing rabbits, including shortening of the mandibular ramus and excessive inferiorly directed bone growth along the lower border of the mandible.