Question: who discovered that fluoride is related to the prevention of dental caries

title: Tooth decay
text: In dentin from the deepest layer to the enamel , the distinct areas affected by caries are the advancing front , the zone of bacterial penetration , and the zone of destruction . The advancing front represents a zone of demineralised dentin due to acid and has no bacteria present . The zones of bacterial penetration and destruction are the locations of invading bacteria and ultimately the decomposition of dentin . The zone of destruction has a more mixed bacterial population where proteolytic enzymes have destroyed the organic matrix . The innermost dentin caries has been reversibly attacked because the collagen matrix is not severely damaged , giving it potential for repair . The outer more superficial zone is highly infected with proteolytic degradation of the collagen matrix and as a result the dentin is irreversibly demineralised . The