Microbiology, 2021

24.2 • Microbial Diseases of the Mouth and Oral Cavity 987
Figure 24.7 Tooth decay occurs in stages. When bacterial biofilms (plaque) develop on teeth, the acids produced gradually dissolve the
enamel, followed by the dentin. Eventually, if left untreated, the lesion may reach the pulp and cause an abscess. (credit: modification of
work by “BruceBlaus”/Wikimedia Commons)
Figure 24.8
(a) Tartar (dental calculus) is visible at the bases of these teeth. The darker deposits higher on the crowns are staining. (b)
This tooth shows only a small amount of visible decay. (c) An X-ray of the same tooth shows that there is a dark area representing more
decay inside the tooth. (d) Removal of a portion of the crown reveals the area of damage. (e) All of the cavity must be removed before filling.
(credit: modification of work by “DRosenbach”/Wikimedia Commons)
Some tooth decay is visible from the outside, but it is not always possible to see all decay or the extent of the
decay. X-ray imaging is used to produce radiographs that can be studied to look for deeper decay and damage
to the root or bone (Figure 24.8). If not detected, the decay can reach the pulp or even spread to the
bloodstream. Painful abscesses can develop.