The quality of the calcified structure of a tooth has no significant role in the incidence of caries. A correlation between calcium metabolism and caries has not been established.
Reference: J. Am. Med. Assoc., 110, 870, 1938.
SCRIVENER, C. A.: Ottawa, Kan. (May 10, 1939).
If caries were a disease due to dietary deficiency, caries would start at the site of nutrition of a tooth, and progress from the inside outward. Caries may be caused by pathologic saliva. A lesion started by dissolution of inorganic matter in enamel may become invaded by bacteria and produce caries in its most common form. It is uncertain whether L. acidophilus occurs in the mouths of caries-susceptibles as a result of the carious process, or whether these organisms cause the caries. Presence in saliva of carbon dioxide, ammonia, sulfocyanates, calcium, phosphorus, chlorides, etc., has little relation to susceptibility. The blood of caries-immunes contains an antibody which is unfavorable for growth of L. acidophilus. Saliva may contain (a) a substance that immunizes teeth against caries, or (b) a substance that disintegrates one or more inorganic chemical combinations in tooth structure. Most consideration, in enamel caries, has been given to enamel-dissolving powers of acid solutions, but some calcium compounds are not easily dissolved in direct ratio to the number of carious or filled first molars when all of these teeth are present. In children from whom one to four first molars have been extracted, there is an increase in number of cavities (fillings) in direct ratio to number of first molars extracted and to number of cavities (fillings) in the remaining first molars. In all cases, children from whom first molars have been extracted show higher incidence of caries than those having a corresponding number of first molars filled or carious but retained. Therefore, (a) number of filled or carious M,’s can be used as an index to incidence of caries in a mouth as a whole; (b) extraction of first permanent molars is a direct cause of increase in caries in these children; and (c) orthodontic and facial sequelae following disturbed occlusion are caused by drifting of remaining teeth in jaw-quadrants from which first permanent molars have been extracted. These factual data show the advantage of retaining first permanent molars; the fallacy of extracting these teeth as an orthodontic measure ; and reasons for immediate replacement or maintenance of the spaces left by extraction of first molars, regardless of the child’s age after one or more of these teeth have been lost.
References: Int. J. Orthod., 1937; J. Am. Den. Assoc., 1938; Bul. Den. Soc. State N. Y., 1938.