Normal maxillary and mandibular growth and dentoalveolar development in Macaca mulatta. A longitudinal cephalometric...

Normal maxillary and mandibular growth and dentoalveolar development were examined in a longitudinal study of 10 male Macaca mulatta monkeys. Metallic implants were placed in the jaws of the monkeys as markers, and head films were taken semiannually from 2 to 5 years of age. The results showed that maxillary and mandibular growth is associated with rotational changes that are mostly in an anterior direction and are about twice as great in the mandible (9.4 degrees) as in the maxilla (4.2 degrees). These rotations are largely masked--about 75% in the maxilla and 90% in the mandible--by modeling within the jaws. Similarly, differential vertical dentoalveolar development almost completely masked the rotation of the occlusal plane that results from the rotation of the jaws, which created the impression that the occlusal plane is stable during growth. Peak growth velocity was reached on average at 3 years of age in the maxilla and mandible, with some individual variation. No major growth changes occurred after 3.5 to 4 years of age.