Growth potential of the rat mandibular condyle as an isogeneic transplant traversing the interparietal suture.

The mandibular condyle of 5-, 10- or 20-day inbred male rats was transplanted across the interparietal suture of male litter-mates and the transverse dimension of the neurocranium was measured from dry skulls at 25 or 35 days. The width of the neurocranium had increased significantly from days 5 or 10 to 25 in the rats with the transplants, whereas the difference from controls was small or non-existent by 35 days. Histological examination showed that the cartilaginous zone was reduced in the transplants at 25 days but that there were still layers of chondrocytes at 35 days. It is suggested that the rat mandibular condyle is endowed with a tissue-separating, interstitial growth potential that, to some extent, is unrelated to mobility, and essentially effected by chondrocyte hypertrophy.