Although many diseases existed among prehistoric men, none were as widespread as dental disorders. Skeletal remains reveal that even in the absence of all other signs of degenerative changes in the skeleton, there were indications of dental diseases. The causes of these degenerative changes include (1) complications that follow natural or acquired damage to teeth or their supporting structures. (2) Maladaptation to various changes following progress of the social order to higher levels of civilization. A specialized organ cannot continue normal existence unless it performs the function for which it was acquired, and in disuse inevitably undergoes alteration. The teeth of modern man have a limited function to perform. A premasticated diet, consisting of prepared soft and starchy foods, refined cereals, and large quantities of sugar, requires very little chewing. Aside from the deleterious effect upon teeth of such a food habit, there is the destructive element associated with overindulgence in sugar. Undernourishment is a deplorable penalty unnecessarily forced upon a majority of the human race, which must culminate in enfeebleness. (3) The masticatory mechanism shows definite effects from frequent physical alterations due to blending of diverse territorial types of man, leading to changes in dental structure, deformities and morbid conditions. Frequent territorial transplantations from relatively permanent surroundings, coupled with abrupt changes from adapted food habits and complicated by the vicissitudes of socio-economic conditions and mating of the physically unfit, not only affect the physical constancy of the individual, but create interferences with his metabolic and other physiologic functions. (4) Further disharmonies that aggravate the already established predisposition to dental breakdown include the ever growing tendency to loss of structural constancy, and to deformation of jaws that crowd the teeth out of alignment and thus create receptacles in which food debris is retained and fermented, the resultant acids dissolving the adjacent enamel.
In summing up the various factors that have resulted in existing derangements of the human dentition, it is necessary to consider the important physiologic phe‑nomena which regulate the wasting and repair of tissues. During the major periods of life, the functional activities of an organ constantly involve balanced processes of disposal of worn-out cells and of compensatory tissue-repair. Nature made no similar provision for the regeneration of teeth and their supporting structures.
References: J. Am. Den. Assoc., 1936 ; J. Den. Res., 1937.