Epidemiologic Studies of Tooth Morphology

¹ Division of Dental Research, Faculty of Dentistry, University of Toronto, Toronto, Canada

Observable differences in the morphology of teeth of humans range from what may be considered to be minor normal variation to gross malformations and, at the extreme end of the scale, complete absence of teeth. Although much of this morphologic variation may be on only academic interest, there are at least four areas of relevance to clinical dentistry and dental science. (1) The general size of the dentition is an important etiologic factor in malocclusion. (2) Variations in caries susceptibility associated with tooth morphology are indicative of developmental predisposition to tooth decay. (3) Tooth contours and embrasure form may have a predisposing influence on the health of the gingiva. (4) Similarity of tooth morphology may be useful in determining zygosity of twins and in forensic dentistry.

The role of genetics in tooth morphology may be to establish the limits of size and to determine general structural characteristics such as numbers of cusps. Because human genetic factors are uncontrollable, the principal objective of epidemiologic studies of tooth morphology is to establish the degree of influence environmental factors operating at the time of tooth development may have on the attainment of the genetic pattern. Epidemiologic studies on human beings supported by animal experiments suggest the possibility of exerting some future control on tooth morphology that may be of clinical significance.