Clinical studies in the development of the dental height

1. 1. Additional evidence has been presented that the teeth and jaws develop independently of each other. 2. 2. During the early years of life the downward growth of the temporal bone and the ramus length growth create the intermaxillary space for the eruption of the deciduous teeth. 3. 3. In ectodermal dysplasia with partial or complete anodontia, the intermaxillary space develops normally since there is no retardation in skeletal development. 4. 4. When there is a general retardation in skeletal development, as seen in pituitary dwarfism, the ramus length growth is markedly impaired and the intermaxillary space fails to increase. This contributes to the late eruption of teeth and decreases the vertical dimension of the maxilla and the size of the body of the mandible. 5. 5. When anodontia occurs in the anterior part of the mouth in young normal children, it is mechanically impossible for the teeth to wedge the jaws apart. This proves that the intermaxillary space which develops is to be attributed to the downward growth of the temporal bone and some ramus length growth. 6. 6. The findings in Case 2 (ectodermal dysplasia) and Case 3 (pituitary dwarfism) indicate that there are specific genetic determinants for the teeth, the maxilla, and the mandible. These observations suggest that the development of the intermaxillary space is predetermined by hereditary factors. In the absence of disease or trauma, normal development can be anticipated.