Craniofacial Structure, Aging and Dental Function: Their Relationships in Adult Human Skeletal Series

Five human skeletal series were examined to discern if post­ adolescent aging, as measured by dental attrition, has significant effects on the morphometrics of the skull. Definite age-related changes were found in the crania of the European, Melanesian and Arikara Indian collections studied. A statistical approach unique to the subject area showed that both size and shape of the adult skull changed with age. Some of the more pronounced aging effects included forward projection of the face, widening of interorbital dimensions, flattening of the frontal bone in profile, retraction of the subnasal region relative to the zygomatic bones, and increases in orbit size and mastoid size. It was assumed that dental attrition not only reflected age, but also the cumulative dental functional forces exerted upon the cranium up to the time of death. Thus, after a consideration of craniofacial biomechanics, it became apparent that many of the age changes were probably direct responses to the aggregate forces of biting and chewing. The results provide support for the theory that some aspects of fossil hominid cranial morphology are adaptations to high levels of dental functional stress and strain. A good case is also made for the possibility that adult aging effects, regardless of their cause, can be a source of noise in some traditional kinds of cranio­ metric investigations.