Editing Human tooth (section)

=== Plaque ===
{{Main|Dental plaque}}

Plaque is a [[biofilm]] consisting of large quantities of various [[bacteria]] that form on teeth.<ref>[https://web.archive.org/web/20080125151851/http://www.ada.org/public/topics/plaque.asp "Oral Health Topics: Plaque"], American Dental Association.</ref> If not removed regularly, plaque buildup can lead to [[periodontal]] problems such as [[gingivitis]]. Given time, plaque can mineralize along the gingiva, forming ''[[Calculus (dental)|tartar]]''. The [[microorganism]]s that form the biofilm are almost entirely [[bacteria]] (mainly [[streptococcus]] and [[Anaerobic organism|anaerobes]]), with the composition varying by location in the mouth.<ref>[http://www.dentistry.leeds.ac.uk/OROFACE/PAGES/micro/micro2.html Introduction to dental plaque] {{webarchive|url=https://web.archive.org/web/20110827094040/http://www.dentistry.leeds.ac.uk/OROFACE/PAGES/micro/micro2.html |date=2011-08-27 }}, [[Leeds Dental Institute]].</ref> ''[[Streptococcus mutans]]'' is the most important bacterium associated with dental caries.

Certain bacteria in the mouth live off the remains of foods, especially [[sugar]]s and starches. In the absence of [[oxygen]] they produce [[lactic acid]], which [[Solvation|dissolves]] the [[calcium]] and [[phosphorus]] in the enamel.<ref name="ross448">{{harvnb|Ross|2002|page=448}}</ref><ref>Ophardt, Charles E. "[https://web.archive.org/web/20141025132424/http://www.elmhurst.edu/~chm/vchembook/548toothdecay.html Sugar and tooth decay]", Elmhurst College.</ref> This process, known as "demineralisation", leads to tooth destruction. [[Saliva]] gradually neutralises the [[acid]]s, which causes the pH of the tooth surface to rise above the critical pH, typically considered to be 5.5. This causes [[remineralisation]], the return of the dissolved minerals to the enamel. If there is sufficient time between the intake of foods then the impact is limited and the teeth can repair themselves. Saliva is unable to penetrate through plaque, however, to neutralize the acid produced by the bacteria.