Growth of the anterior dental arch in black American children: a longitudinal study from 3 to 18 years of age.

Dental arch size and form change systematically because of tooth emergence and because teeth migrate into shorter and broader arch forms in the deciduous dentition and again in the permanent dentition. The present longitudinal analysis describes changes in arch form in a cohort of 52 black American children (Nashville, Tenn) between the ages of 3 and 18 years. The anterior (incisor-canine) arch dimensions were analyzed. Incisor-to-canine depth remained static in both arches between 3 and 5 years but shortened significantly between 12 and 18 years. Intercanine width broadened significantly in both arches, first during the deciduous dentition, then again as the primary teeth were supplanted by the permanent incisors and canines. But there was no change in intercanine width once the permanent canines were in functional occlusion (approximately 11-18 years). These changes alter anterior arch form (the ratio depth/width). This index decreased significantly during the deciduous phase as the arches broadened; the index increased from 6 to 10 years as teeth were replaced, then again decreased during the duration of the study (approximately 10-18 years). Dimensions of these black American children all exceed comparable values for white American children, although the anterior shapes are indistinguishable. The present data focus attention on the dynamics of arch form in which considerable, protracted change occurs by physiologic migration, not just during the short phase of tooth replacement.