Changing occlusal variation in Pima Amerinds

Abstract

Occlusal variables and arch measurements have been recorded on 341 Pima Amerinds pertaining to two samples, one of older individuals raised on traditional diets, the other of younger individuals raised on refined commercial foods that are typical of modern urbanized people. Permanent dental occlusion is significantly more variable from defined ideals in the younger sample, despite their fewer deformities resulting from progressive aging. The youths had relatively narrower palates, correlating with a general trend among industrialized populations and also among experimental animals fed soft diets. Relative rate of deciduous tooth loss and replacement did not correlate with any occlusal variable.

Changes in mandibular morphology from the Jomon to modern periods in Eastern Japan

“…Cases of dental arch narrowing within one or two generations have been reported in the human mandible (Corruccini et al, 1983b;Lavelle, 1973) and maxilla (Corruccini and Whitley, 1981;Corruccini et al, 1983a,b;Lavelle, 1973;see Corruccini, 1991 for a review). In addition, in a study of the relative heritability of human mandibular morphology (Watnick, 1977), the angular region was reported to receive the greatest environmental influence.…”

Genetics versus environment in the aetiology of malocclusion

“…What the evidence tells us is that Class II malocclusions with increased overbites never occur in the ancestral environment; however, within one OPINION or two generations of adopting a modern urban culture they are rife. [9][10][11][12] Class II anterior open bites and Class III malocclusions do occur and, as far as we know, always have occurred in nature. Might it not be reasonable to suppose that heredity plays a more important role in the aetiology of the latter two, and function/environment in the former?…”

“…1 Most of the evidence on occlusal variation in either historical civilisations [2][3][4][5][6][7][8] or in modern pre-industrial populations [9][10][11][12] demonstrates that the prevalence of malocclusion in these groups is very low and usually coupled with high levels of attritive tooth wear. Tooth wear is an important element in this discussion, as it is posited that once a Class I occlusion is established during childhood, it is maintained by a process of gradual mesial…”

Technical Note: The Definition of New Dental Morphological Variants Related to Malocclusion

“…Dental crowding and malocclusion are often discussed in relation to the adoption of agriculture and the introduction of soft foods as part of the masticatory-functional hypothesis (Carlson and Van Gerven, 1977;Corruccini, 1984;Corruccini et al, 1983;Larsen, 2015). In this discussion, malocclusion encompasses two distinct features: malalignment of the teeth (i.e., crowding) and malalignment of the jaws (i.e., overbite and underbite).…”