| Abstract: | There have been numerous studies on variability and correlation in dental crown size, but the significance of the resulting patterns remains unclear. Regions of low variation and high correlation have been hypothesized to represent the poles of Butler's morphological fields, to be related to absolute tooth size, or to be related to morphological complexity of the teeth and functional efficiency. Variation and correlation of tooth lengths and breadths were investigated in 138 red colobus monkeys to further assess the relations among size associations, crown morphology, and absolute tooth size. In the maxilla and mandible, the postcanine teeth are the most highly correlated and least variable, followed by the incisors, then the canines. There are also lower correlations between premolars and molars than within either group. While there appears to be a relation between degree of morphological differentiation and levels of correlation and variation, there are no notable differences in the correlation of opponents along the dental arcade, which is the most important functional consideration. This suggests that different levels of correlation and variation within upper or lower teeth are “artifacts” of tooth dimensions that contribute to different geometric designs in different tooth groups as the germs develop. This morphological effect is coupled with the influence of integration fields, indicated by higher variability and lower correlations of the third molar, the largest or most molarized tooth. It is concluded that there are wide functional tolerances in occlusion with respect to the gross dimensions of dental crowns and their interrelationships. |
