Editing Toothache (section)

====Pulpitis====
[[Pulpitis]] (inflammation of the pulp) can be triggered by various stimuli (insults), including mechanical, thermal, chemical, and bacterial irritants, or rarely [[Aerodontalgia|barometric changes]] and [[ionizing radiation]].<ref name=Neville2001>{{cite book|vauthors=Neville BW, Damm DD, Allen CA, Bouquot JE |title=Oral & maxillofacial pathology|year=2002|publisher=W.B. Saunders|location=Philadelphia|isbn=978-0-7216-9003-2|edition=2nd}}</ref>{{rp}} Common causes include tooth decay, dental trauma (such as a crack or fracture), or a filling with an imperfect seal.

Because the pulp is encased in a rigid outer shell, there is no space to accommodate swelling caused by inflammation. Inflammation therefore increases pressure in the pulp system, potentially compressing the blood vessels which supply the pulp.  This may lead to [[ischemia]] (lack of oxygen) and [[necrosis]] (tissue death). Pulpitis is termed ''reversible'' when the inflamed pulp is capable of returning to a state of health, and ''irreversible'' when [[pulp necrosis]] is inevitable.<ref name=Hargreaves2011 />{{rp|36–37}}

Reversible pulpitis is characterized by short-lasting pain triggered by cold and sometimes heat.<ref name=Cawson2008 /> The symptoms of reversible pulpitis may disappear, either because the noxious stimulus is removed, such as when dental decay is removed and a filling placed, or because new layers of dentin ([[tertiary dentin]]) have been produced inside the pulp chamber, insulating against the stimulus. Irreversible pulpitis causes spontaneous or lingering pain in response to cold.<ref name="Hupp 2008">{{cite book|vauthors=Hupp JR, Ellis E, Tucker MR |title=Contemporary oral and maxillofacial surgery|year=2008|publisher=Mosby Elsevier|location=St. Louis, Mo.|isbn=978-0-323-04903-0|edition=5th}}</ref>{{rp|619–627}}