Studies of the manifestations of the carious lesion showed reactions comparable to acute, chronic and arrested stages of other disease lesions. Experimentally arrested and spontaneously arrested carious lesions are similar. Experimental arrest of caries followed removal of the decay, and of those portions of teeth that favor accumulation and retention of food and debris. Clinical evidence indicates that the masticatory function is important as an aid to the arrest of caries (1938).
A study of the incidence of caries in 1,000 Chinese (1932), included (a) 219 females, 781 males-581 ranging from 5 to 15 years of age, inclusive ; 307, from 16 to 25 years, inclusive ; 86, from 26 to 35 years, inclusive; 26 being over 36 years of age ; 4 and (b) 20,778 permanent teeth, 445 of which (2.1 percent) were carious. Of the 963 individuals having permanent teeth, 404 (41.9 percent) had caries of this dentition—an average of 1.1 decayed teeth per individual. Of a total of 5,173 deciduous teeth examined, 832 (16.1 percent) were carious. Of the group having deciduous teeth, 51.0 percent exhibited caries of this dentition—an average of 3.6 carious deciduous teeth per individual. In Peiping and its immediate vicinity, of 865 members of the entire group 376 (43.4 percent) had caries. Of a second group of 110 persons in Tai Yuan Fu (Shansi) 28 (25.5 percent) had caries. A third group of 25 individuals, in Mongolia, were entirely free from caries (1932).
Carious lesions in 3.9 percent of 76 monkeys—studied by clinical and histological methods—were grossly and histologically similar to, or identical with, those in man. These animals were not intentionally deprived of any dietary element that might interfere with normal growth, development, or maintenance of health (1937).
References: J. Den. Res., 1932, 1938; Yale J. Biol. Med. (with S. S. Arnim), 1937.