Editing Human tooth (section)

== Tooth decay ==
{{See also|Tooth pathology}}

=== 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.

===Caries (cavities)===
[[File:Toothdecay.png|right|thumb|150px|Advanced tooth decay on a premolar]]
{{Main|Dental caries}}
Dental caries (cavities), described as "tooth decay", is an infectious disease which damages the structures of teeth.<ref name="medline">[https://www.nlm.nih.gov/medlineplus/ency/article/001055.htm Dental Cavities], ''MedlinePlus Medical Encyclopedia''.</ref> The disease can lead to [[pain]], [[tooth loss]], and infection. Dental caries has a long history, with evidence showing the disease was present in the [[Bronze Age]], [[Iron Age]], and [[Middle Ages]] but also prior to the [[Neolithic]] period.<ref name=SeilerSpielman2013>{{cite journal| vauthors=Seiler R, Spielman AI, Zink A, Rühli F| title=Oral pathologies of the Neolithic Iceman, c.3,300 BC. | journal=European Journal of Oral Sciences | year= 2013 | volume= 121 | issue= 3 Pt 1 | pages= 137–41 | pmid=23659234 | doi=10.1111/eos.12037 | type= Historical Article. Research Support, Non-U.S. Gov't }}</ref> The largest increases in the prevalence of caries have been associated with diet changes.<ref name="suddickhistorical">{{Cite journal|vauthors=Suddick RP, Harris NO |title=Historical perspectives of oral biology: a series |journal=Crit. Rev. Oral Biol. Med. |volume=1 |issue=2 |pages=135–51 |year=1990 |pmid=2129621 |doi=10.1177/10454411900010020301|doi-access=free }}</ref> Today, caries remains one of the most common diseases throughout the world. In the United States, dental caries is the most common [[chronic (medicine)|chronic]] childhood disease, being at least five times more common than [[asthma]].<ref>[https://web.archive.org/web/20101219084119/http://healthypeople.gov/Document/HTML/Volume2/21Oral.htm Healthy People: 2010]. Healthy People.gov.</ref> Countries that have experienced an overall decrease in cases of tooth decay continue to have a disparity in the distribution of the disease.<ref name="DCPP">"[https://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=dcp2.section.5380 Dental caries]", from the Disease Control Priorities Project.</ref> Among children in the United States and Europe, 60–80% of cases of dental caries occur in 20% of the population.<ref name="Tougersugars">{{Cite journal|vauthors=Touger-Decker R, van Loveren C |title=Sugars and dental caries |journal=Am. J. Clin. Nutr. |volume=78 |issue=4 |pages=881S–892S |year=2003|pmid=14522753 |doi=10.1093/ajcn/78.4.881S |doi-access=free }}</ref>

Tooth decay is caused by certain types of acid-producing bacteria which cause the most damage in the presence of [[fermentation (food)|fermentable]] [[carbohydrate]]s such as [[sucrose]], [[fructose]], and [[glucose]].<ref name="Hardie1982">{{Cite journal|author=Hardie JM |title=The microbiology of dental caries |journal=Dent Update |volume=9 |issue=4 |pages=199–200, 202–4, 206–8 |year=1982|pmid=6959931}}</ref><ref name="holloway1983">{{Cite journal|author=Moore WJ |title=The role of sugar in the aetiology of dental caries. 1. Sugar and the antiquity of dental caries |journal=J Dent |volume=11 |issue=3 |pages=189–90 |year=1983|pmid=6358295 |doi= 10.1016/0300-5712(83)90182-3|last2=Moore|first2=W.J.}}</ref> The resulting acidic levels in the mouth affect teeth because a tooth's special mineral content causes it to be sensitive to low [[pH]]. Depending on the extent of tooth destruction, various treatments can be used to [[dental restoration|restore]] teeth to proper form, function, and [[aesthetics]], but there is no known method to [[regeneration (biology)|regenerate]] large amounts of tooth structure. Instead, dental health organizations advocate preventive and prophylactic measures, such as regular [[oral hygiene]] and dietary modifications, to avoid dental caries.<ref name = "adaoralhealth"/>