A localised pathological process involving the demineralisation of hard tooth tissue, caused by the action of bacteria on fermentable carbohydrates in the diet.

'The Acidogenic Theory' Miller 1850 Multifactoral

Acids are produced by bacterial fermentation of dietary carbohydrates. The acids are responsible for the demineralisation of dental hard tissue.

1. Personal factors - education, income, socioeconomic status and behaviours 2. The oral environment - fluoride ions present, saliva flow and composition, prosthesis present 3. Keyes circles - factors that directly relate to caries development

- 6.5pH - 5.5pH - 6.2pH

caries

1. Increases the resistance of the enamel to demineralisation by the formation of fluorapatite 2. Fluoride reservoir promotes remineralisation 3. Inhibits acid generation from plaque bacteria glycolysis

Irreversible

Acidogenic Aciduric

Bacteria that are able to produce acids from the metabolism of dietary carbohydrates S. Mutans

-Bacteria which thrive in low pH environments

Restoration of the tooth surface

1. Plaque Micro organisms 2. Substrate (Dietry carbohydrates 3. Time 4. Susceptible tooth

- Bacteria produce acids from the metabolism of dietary carbohydrates

- Strep. Mutans - Synthesis dextran which bind plaque, increasing the biofilm matrix - Store intercellular polysaccharides for use when substrate not available, maintaining the acidic pH of biofilm