Some Observations on the Association of the Products of Protein Putrefaction with Dental Caries Activity

Abstract

The suscepti-bility of endemic pellagrins to periodontal disease and their relative immunity to dental caries have been reported from different parts of the world. The lowered caries incidence cannot be wholly explained on the basis of diet, oral hygiene, fluorine, or lack of the nutritional requirements of the Lactobacillus acidophilus. Dental caries is primarily the result of the breakdown of carbohydrates which is acid producing in nature and periodontal disease involves the production of toxic products which are alkaline in effect. The nature of the processes of dental caries and of gross periodontal disease suggested that the products produced during the breakdown of tissue protein may in some way affect the development of dental caries. Since indole production has been correlated with the severity of periodontal disease, it was decided to determine whether indole and its related compound indole-3-acetic acid both produced during the bacterial decomposition of tryptophane possessed properties as inhibitors of acid production in saliva. The methods employed were the Fosdick, Hansen and Epple test for dental caries activity and the addition of various amts. of indole and indole-3-acetic acid to yeast extract dextrose broth inoculated with a pure culture of L. acidophilus recovered from a carious lesion. Indole in amts. of 7.5 or 10 mg. and indole-3-acetic acid in 10 mg. quantities partially or completely inhibited acid production in vitro in 10 ml. samples of saliva in 50 of the 51 patients studied. Both compounds inhibited the growth and acid production of the L. acidophilus partially or completely when added in concs. ranging from 2.5 to 6 mg. for indole and 5 to 7.5 mg. for indole-3-acetic acid. The findings offer a working hypothesis that the products of protein putrefaction may to some extent be responsible for the decreased incidence of dental caries accompanied by extensive periodontal disease which is often seen in endemic pellagrins and persons with associated chronic vitamin B complex deficiencies.