The effect of dietary consistency on gross and histologic morphology in the craniofacial region of young rats.

Three groups of weanling rats and three groups of juvenile rats were fed diets which differed in physical consistency for periods of 5 and 8 weeks, respectively. In both the weanling and juvenile rats, one group was fed a soft diet, a second group was fed a hard diet, and a third group was initially fed the soft diet and then was switched to the hard diet for the remainder of the experimental period. The effects of these differences in dietary consistency on gross and histologic morphology of the craniofacial region were examined. Significant differences were found in the dimensions and morphology of the condyle and condylar cartilage as a result of the differences in dietary consistency in both the weanling and juvenile groups. Soft-diet rats generally had smaller condyles and a thinner layer of condylar cartilage than either hard-diet or soft/hard-diet rats. Little change, however, was found in the overall dimensions of the mandible and maxilla in any of the groups of rats.