Unilateral masticatory function changes the proteoglycan content of mandibular condylar cartilage in rabbit

Unilateral masticatory function was induced in 10-day-old rabbits by grinding the right side molars out of occlusion under general anesthesia. The grinding procedure was repeated twice a week thereafter. They were killed at the ages of 25 and 35 days. Rabbits of the same age with uninterfered occlusions served as controls. The changes in articular cartilage of the mandibular condyle were studied biochemically and histochemically. There was a significant decrease in the proteoglycan content of the condylar cartilage in both groups of animals subjected to molar grinding compared to the animals with untouched occlusions. Especially the amount of aggregating proteoglycans was reduced. The condylar cartilage matrix synthesis is sensitive to loading produced by masticatory function during growth. The mechanical properties of the articular cartilage after a period of unilateral mastication will be impaired and it is possible that this makes the joint cartilage more susceptible to pathological events.