Caries & tooth decay
Tooth decay has been present throughout human history, from early hominids millions of years ago, to modern humans. It wasn’t until the 19th century that the presence of dental decay had a dramatic rise, as the Industrial Revolution brought on items such as refined sugars and flour. Worldwide, approximately 2.3 billion people (32% of the population) have dental caries in their permanent teeth qualifying it as a pandemic. Nearly all adults will have or have had dental caries at some point in time. The disease is most common in the developed world due to greater simple sugar consumption and less common in the developing world.
Pellicle Formation
1. Pellicle forms iummediately on a clean tooth surface
2. Pellicle is protective as it slows diffusion of acids, chelating agents, calcium, and phosphate ions
3. Pellicle enables attachment and colonization of microbial species in the early stages of biofilm formation
Biofilm Formation
1. Biofilm builds on the pellicle layer
2. Key stages of biofilm formation are: (a) attachment and colonization, (b) growth and proliferation, (c) maturation and detachment
3. Gram + Cocci, mainly Streptococci are the early colonizers
Dietary Sugars Diffuse Into The Biofilm
1. Acidogenic bacteria convert sucrose to dextran - a polysaccharide that helps form the sticky biofilm matrix
Fermantation Produces Acid Leading to Demineralization
1. Fermantation of sugars lowers biofilm pH
2. Lower pH causes a shift in biofilm ecology
3. Strep. Mutans and Lactobacilli proliferate
4. More acid production leads to demineralization and the sub-surface lesion
Demineralization and Remineralization
1. The sub-surface lesion is reverible
2. Less sugar leads to less acid production
3. Fewer H+ ions, the presence of F- ions, and saturation of Ca++ ions will encourage Ca++ to diffuse back into the lesion