Prevention and reversal of dental caries: role of low level fluoride

Dental caries is a bacterially based disease that progresses when acid prod uced by bacterial action on dietary fermentable carbohydrates diffuses into the tooth and dissolves the mineral, that is, demineralization. Pathologic al factors including acidogenic bacteria (mutans streptococci and lactobaci lli), salivary dysfunction, and dietary carbohydrates are related to caries progression. Protective factors which include salivary calcium, phosphate and proteins, salivary flow and fluoride in saliva can balance, prevent or reverse dental caries. Fluoride works primarily via topical mechanisms whic h include (1) inhibition of demineralization at the crystal surfaces inside the tooth, (2) enhancement of remineralization at the crystal surfaces (th e resulting remineralized layer is very resistant to acid attack), and (3) inhibition of bacterial enzymes. Fluoride in drinking water and in fluoride -containing products reduces tooth decay via these mechanisms. Low but slig htly elevated levels of fluoride in saliva and plaque provided from these s ources help prevent and reverse caries by inhibiting demineralization and e nhancing remineralization. The level of fluoride incorporated into dental m ineral by systemic ingestion is insufficient to play a significant role in caries prevention. The effect of systemically ingested fluoride on caries i s minimal. Fluoride "supplements" can be best used as a topical delivery sy stem by sucking or chewing tablets or lozenges prior to ingestion.