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Hominid dental morphology evolution
One of the major changes throughout hominid evolution, are the changes to the dental morphology and jaw. These changes were driven by the types and processing of food eaten. The evolution of the jaw is thought to have facilitated encephalization, speech, and the formation of the chin, a uniquely human feature.
== Background ==
Today, humans possess 32 permanent teeth with a dental formula of 2123.〔Scott, G. R., & Turner, C. G. (1997). The anthropology of modern human teeth: Dental morphology and its variation in recent human populations. Cambridge ; New York: Cambridge University Press.〕 This breaks down to four incisors, two canines, four premolars, and six molars on the upper and lower sets of teeth.〔Scott, G. R., & Turner, C. G. (1997). The anthropology of modern human teeth: Dental morphology and its variation in recent human populations. Cambridge ; New York: Cambridge University Press.〕 In modern day humans, incisors are generally spatulate with a single root while canines are also single rooted but are single cusped and conical.〔Scott, G. R., & Turner, C. G. (1997). The anthropology of modern human teeth: Dental morphology and its variation in recent human populations. Cambridge ; New York: Cambridge University Press.〕 Premolars are bicuspid while molars are multi-cuspid.〔Scott, G. R., & Turner, C. G. (1997). The anthropology of modern human teeth: Dental morphology and its variation in recent human populations. Cambridge ; New York: Cambridge University Press.〕 The upper molars have three roots while the lower molars have two roots.〔Scott, G. R., & Turner, C. G. (1997). The anthropology of modern human teeth: Dental morphology and its variation in recent human populations. Cambridge ; New York: Cambridge University Press.〕
General patterns of dental morphological evolution throughout human evolution include a reduction in facial prognathism, the presence of a Y5 cusp pattern, the formation of a parabolic palate and the loss of the diastema.
Human teeth are made of dentin and are covered by enamel in the areas that are exposed.〔M. Staines, W. H. Robinson and J. A. A. Hood (1981). Spherical indentation of tooth enamel. Journal of Materials Science 16 (9): 2551–2556.doi:10.1007/bf01113595.〕 Enamel, itself, is composed of hydroxyapatite, a calcium phosphate crystal.〔M. Staines, W. H. Robinson and J. A. A. Hood (1981). Spherical indentation of tooth enamel. Journal of Materials Science 16 (9): 2551–2556.doi:10.1007/bf01113595.〕 The various types of human teeth perform different functions. Incisors are used to cut food, canines are used to tear food, and the premolars and molars are used to crush and grind food.〔Scott, G. R., & Turner, C. G. (1997). The anthropology of modern human teeth: Dental morphology and its variation in recent human populations. Cambridge ; New York: Cambridge University Press.〕
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