Effects of functional loading on the growth of the mandibular condyle and craniofacial adaptation. A histological and morphometrical study.

The purpose of the present study is to determine whether or not functional loading is critical for the normal growth and maintenance of the mandibular condyle. The effect of altered condylar function on craniofacial morphology, a craniofacial adaptation, was also examined. Fifty -one rats, 5 weeks of age, were divided into 3 groups: a condylotomized group without reduction (unfixed), a condylotomized group where the condyle was repositioned, and a sham-operated control group. Six weeks after the unilateral surgery, the animals were sacrificed and the tissue was harvested.The present results support the contention that, within limits, functional loading on the condyles may create a condylar growth closer to normal than in a static condition, although craniofacial adaptation occurs when the condylar function is deformed. When the separated condyles were refixed, the condyles had functional loading when the mandibles moved. On the other hand, nonfixed isolated condyles may only show resorption. Functional loading, therefore, is suggested to be critical for mandibular condyle growth, and craniofacial adaptation is suggested to occur when condylar functions are abnormal.