A preliminary study of the morphology of the upper gum pad at the age of 6 months.

Longitudinal records of 109 individuals born at full term and 30 pairs of twins have been used to study factors which determine the form of the upper gum pad at the age of six months and before the emergence of teeth. The contribution of heredity was found to be less than at birth, and that derived from the underlying teeth to have increased during the first six months of life. It is concluded that the shape of the alveolar process may be modified by physical forces such as sucking habits before teeth erupt into the mouth.