Teeth, like other organs, are continuously affected by numerous metabolic activities in the body, succumbing to adverse conditions and being protected by favorable ones. Consideration of the cause of caries, with due regard for systemic conditions, includes (1) variations in structure of teeth during development—accounting for differences in resistance to caries—due not only to macroscopic malformation (non-coalesced pits and fissures, hypoplasia, hyperplasia, or other irregularity), but also to micro-anatomical or microchemical abnormality (frequently overlooked in explanations of such clinical conditions as decalcification on only one of two contacting approximal surfaces) ; (2) changing nature of adjacent tissues (gingiva, mucosa, glands, secretions, bone investments) that influence functional capacities in the oral cavity; (3) fluctuating environmental effects of salivary components (inorganic and organic, soluble and suspended unformed constituents, and cellular entities) acting individually or collectively.
Particular focus on the foregoing considerations is warranted by (a) findings that indicate statistically distinct pictures for various oral manifestations which differ especially in number of constituents showing divergences from normal average levels, i.e., average levels in subjects within the age-range of 5 to 20 years who, so far as medico-dental clinical and laboratory examinations can determine, have no pathological involvement. (b) In erosion-active cases, average data for salivary H-ion concentration, pH, calcium, magnesium, inorganic phosphate, lipid phosphorus, cholesterol and protein are above those for the corresponding constituents of saliva of normal persons. (c) In caries-active individuals, non-overlapping values appear only for pH, magnesium, lipid phosphorus, cholesterol and protein.
(d) There seem to be two types of erosion and of caries, one of each being associated with markedly low concentrations of these salivary constituents, the other with very high levels.
The existence of a common mechanism seems probable—a tendency to the type of derangement often associated with acidic states in the body. (a) Impetus was added to this view when it was found that cardiac malfunction—highly active and nervous conditions without oral lesions—are usually accompanied by salivary compositions similar to those for caries or erosion. (b) Studies of diet, as one possible base for the probable unbalance of positive and negative ions, revealed great preponderance of acid potentialities (particularly cereal, bread, cake, and purified grain-products generally). (c) Among the economic lower-income groups, the acid/base ratio ranges from 5 to 1, the smaller obtaining only infrequently and not always in relation to economic status. (d) Nutritional regulation, with quantitative control of the seven food types—in addition to other physiologic needs of the individual—has brought aberrant salivary values within normal range.
(e) Accumulating clinical evidence points to decrease of susceptibility to caries and erosion under such a regime. (f) Notwithstanding the role of local factors (tooth structure, microscopic flora, local dental hygiene), general dental health and specific resistance to caries are resultants of conditions that maintain life and health for the body as a whole. (g) Dental diseases are effects of specific syndromes to which the entire organism contributes. All requirements for good health in mother-to-be, and in child throughout life, should be safeguarded.
References: J. Am. Col. Den., 1936; J. Den. Res., 1937, 1938; J. Am. Den. Assoc., 1938; J. Am. Pub. Health Assoc., 1938; J. Periodon., 1938.