The Effect of Chemicals on Microorganisms 217 



water supplies has been gaining favor in recent years. Such treat- 

 ment is known as fluoridation. 



A small, but active, minority of opponents to this procedure 

 have made fluoridation a lively topic in state legislatures, and the 

 uphill battle on the part of public health authorities is a repeat 

 performance of the struggle experienced in instituting pasteurization 

 of milk and chlorination of public water supplies. Meddling with 

 nature, according to the opponents, is a dangerous practice. 

 Enough research has been conducted, however, to indicate the 

 strong desirability of fluoridation, and in time the practice will 

 undoubtedly be just as common as chlorination. Published claims 

 indicate that up to 60% reduction in tooth decay can be accom- 

 plished with controlled fluoridation of water supplies. 



In localities where the practice has not been introduced, young 

 children can avail themselves of topical application (by their 

 dentists or dental hygienists) of a 2% solution of sodium fluoride. 

 The procedure involves painting the teeth with this solution for 

 four successive weeks at the ages of three, seven, and ten. There 

 are indications that pronounced reduction in dental caries results 

 from such applications of the chemical. Just what the mechanism 

 is that makes topical application effective is still not clearly under- 

 stood. Some workers in the field have suggested that a direct 

 combination occurs with the tooth enamel. Others feel that a pro- 

 longed bactericidal effect may account for the success of the prac- 

 tice. Whatever the mechanism, decided reduction in tooth decay 

 is reported from widely scattered areas throughout the United 

 States. 



There appears to be a relationship between consumption of 

 refined sugar and tooth decay. The bacteria in the mouth are 

 able to ferment these sugars and destruction of tooth enamel is a 

 direct result, according to some oral hygienists. Thorough brush- 

 ing of the teeth immediately after each meal appears to reduce the 

 opportunity for bacteria to produce destructive acids from food 

 residues, especially in the hidden crevices of the teeth. The use 

 of dental floss is an important phase of oral hygiene, particularly 



