Where do cavities usually occur?

Cavities can occur around the edges, or a margin, of fillings, and is common for older adults. Over the years, these fillings may weaken and tend to fracture and leak around the edges. Bacteria accumulate in these tiny crevices causing acid to build up which leads to decay.

Recession of the gums away from the teeth, combined with an increased incidence of gum disease, can expose tooth roots to plaque. Tooth roots are susceptible to decay and are more sensitive to touch and to hot and cold. It’s common for people over age 50 to have tooth-root decay.

Cavities occur most often in the back teeth, called premolars and molars, which typically have depressions and grooves, known as "pits and fissures". Even though these surfaces are helpful in grinding food, they can accumulate residue from food and drink. Back teeth are also harder than the smoother front teeth to maintain adequate cleanliness, and so plaque can develop more easily and acids can be formed to destroy them. Also, teeth that have little fluoride as protection are more susceptible to developing cavities.