Editing Tooth decay (section)

===Exposure===
[[File:Stephan curve.png|thumb|"Stephan curve", showing sudden decrease in plaque pH following glucose rinse, which returns to normal after 30–60&nbsp;min. Net demineralization of dental hard tissues occurs below the critical pH (5.5), shown in yellow.]]
The frequency with which teeth are exposed to cariogenic (acidic) environments affects the likelihood of caries development.{{citation needed|date=February 2020}} After meals or [[snack food|snack]]s, the bacteria in the mouth [[Metabolism|metabolize]] sugar, resulting in an acidic by-product that decreases pH. As time progresses, the pH returns to normal due to the buffering capacity of [[saliva]] and the dissolved mineral content of tooth surfaces. During every exposure to the acidic environment, portions of the inorganic mineral content at the surface of teeth dissolve and can remain dissolved for two hours.<ref>[http://www.dent.ucla.edu/ce/caries/ Dental Caries] {{webarchive|url=https://web.archive.org/web/20060630205712/http://www.dent.ucla.edu/ce/caries/ |date=2006-06-30 }}, hosted on the University of California Los Angeles School of Dentistry website. Page accessed August 14, 2006.</ref> Since teeth are vulnerable during these acidic periods, the development of dental caries relies heavily on the frequency of acid exposure.

The carious process can begin within days of a tooth's erupting into the mouth if the diet is sufficiently rich in suitable carbohydrates. Evidence suggests that the introduction of fluoride treatments has slowed the process.<ref name="summit75">Summit, James B., J. William Robbins, and Richard S. Schwartz. "[[iarchive:fundamentalsofop0002unse/page/75/mode/2up|Fundamentals of Operative Dentistry: A Contemporary Approach.]]" 2nd edition. Carol Stream, Illinois, Quintessence Publishing Co, Inc, 2001, p. 75. {{ISBN|0-86715-382-2}}.</ref> Proximal caries take an average of four years to pass through enamel in permanent teeth. Because the cementum enveloping the root surface is not nearly as durable as the enamel encasing the [[Crown (tooth)|crown]], root caries tend to progress much more rapidly than decay on other surfaces. The progression and loss of mineralization on the root surface is 2.5 times faster than caries in enamel. In very severe cases where oral hygiene is very poor and where the diet is very rich in fermentable carbohydrates, caries may cause cavities within months of tooth eruption. This can occur, for example, when children continuously drink sugary drinks from baby bottles (see later discussion).