Metrical analysis of growth changes in the jaws and teeth of normal, protein deficient and calorie deficient pigs.

Weanling pigs were separated into three groups: control animals were allowed unlimited food; protein deficient animals were allowed unlimited carbohydrate or fat but restricted in protein intake; calorie deficient animals were restricted in total food intake. The skulls and teeth of animals killed at one year and at two years of age were measured from radiographs, and from the results were derived the following conclusions: (1) Pigs fed on protein and on calorie deficient diets all showed considerable retardation of the growth of jaws and teeth, consistently more severe in the calorie deficient than in the protein deficient animals. (2) The shape of the mandible was altered by both types of malnutrition, the height of the ascending ramus being reduced to a greater extent than either its anteroposterior width or the length of the body of the mandible. The labial alveolar process became more proclined with increasingly severe malnutrition. (3) The upper and lower jaws were retarded to a similar extent in both groups of experimentally malnourished animals. (4) Retardation of tooth growth was less severe than that of jaw growth. (5) Contralateral asymmetry of molar crown size in the protein deficient animals was initally quite marked, but when the teeth were approaching their final size the asymmetry was no greater than in control animals.