1959 Volume 9 Issue 1 Pages 74-77
In October of 1957, a Dental Mass Medical Examination of 191 factories and active plants in Tokyo was undergone by members of the Tokyo Dental Association, and 15,104 individual cards obtained on that occasion, among which those perfectly filled up in description were the very objects of this study whatever. The factories and active plants to which the laborers belonged were arranged according to Japan Standard Industry Classification and the observation, according to the distinctions of their professions, was devoted at the same time, in which the authors endeavoured to have the numbers of the works classified and observed dividing them into eight groups (a) 1-50, (b) 51-100, (c) 101-200, (d) 201-300, (e) 301-400, (f) 401-500, (g) 501-1000, and (h) 1001-2000, laborers.
The calculation of statistical value obtained concerning teeth according their professions and the numbers of laborers, on D.M.F., missings, dummies, treated teeth invaluing false-teeth, both. common decayed teeth and decayedteeth, furthermore, on subdivisions according to the conditions of caries as (A) Surface caries, (B) Deep seated caries and (C) Root stump caries was minutely made. As for each of them, the rate of laborers with caries was calculated, moreover, if necessary, the cor-relation coefficient (r) and its significance decided by decimal instance, which came finally to the following results:
I) Observation on each profession.
(1) The rates of laborers with caries and an average number of teeth per person were in D.M.F. in missing company showed especially low degrees, and transport communication industry and electric, gas, water industry ones showed rather high value. In missings of teeth, wholesale, ratil sale service ones showed the lowest, while transport and communication industry laborers, the highest. Intreated cases, mining lower and transport and communication industry, higher. In decayed teeth, whole sale, ratail sale showed lower, while degrees electric, gas, water industry ones higher.
(2) The value of surface caries and deep seated caries of each profession showed cor-relation.
II) Observations on each member of laborers.
(1) The rates showed in each statistical value and an average number of teeth per person were both not so remarkable in tendency in D.M.F., but in missings, surface caries and root stump caries, there was a tendency of decrease, according as the numbers of laborers increased, while treated teeth, common decayed and deep seated caries, the class of 100-300 (c), (d) showed the lowest value.
(2) The value of surface caries and deep seated caries of each classified number showed rather converse cor-relation.
(3) From those examined, in the factories and active plants especially the ones small in number less than 50 members, it, generally, could observed in D.M.F. and its subdivision (decayed, missing and filled permanent teeth), remarkably higher tendency. Therefore, the possitive necessity for the dental hygiene supervision in detail should anyway be recognized.
