How cavities form

Teeth naturally self-repair as minerals found in saliva replace material lost by normal wear and tear.

Bacteria interrupts this process, opening up holes (cavities) in teeth that can progress into various stages of tooth decay.

Normal state: remineralization

Minerals in saliva like calcium naturally deposit onto and bond with enamel, repairing any deficiencies to maintain a strong, healthy tooth surface.

This natural process is called remineralization.

Conditions that form a cavity

Bacterial colonization

Naturally occurring bacteria in the mouth attach to the pellicle layer and begin to digest sugars from food (see "sugar and cavities" below).

Plaque formation

The bacteria produce a colorless waste called plaque.

Plaque forms a protective layer around bacteria, supporting further bacterial growth.


Minerals from saliva bond with plaque, creating a very hard yellow or brown-stained material called tartar.


Bacteria produce a waste that is highly acidic, and plaque seals this acidic waste against the tooth surface.

Dissolving enamel (demineralization)

Acid dissolves the calcium in enamel rods and supporting structure. Minerals are lost and not replaced by the normal mineral delivery process.

The equilibrium has now shifted from remineralization to demineralization.

Cavity repair

Harmful elements must be removed so remineralization can resume.

(Note that tooth damage may progress beyond naturally repairable conditions —professional diagnosis is recommended.)

Home care

Brushing and flossing disrupts bacterial colonization and plaque formation.

Tartar removal (professional care)

Tartar deposits must be scraped off. This is done through professional cleaning.

A dental hygienist, must work carefully around delicate mouth anatomy while applying necessary force to very hard, calcified tartar deposits.

Enamel structure repair

With harmful elements removed, acid levels (pH) in the mouth stabilize and remineralization resumes, repairing damaged enamel structure.


Fluoride — introduced via prescription toothpaste, for example — can bond with the outer tooth surface for a more acid resistant tooth.

Biofilm (Pellicle) layer

A protective film called dental biofilm forms on the enamel from proteins in saliva moments after chewing or brushing. This layer regulates salivary calcium deposits and protects the enamel against acids from bacterial waste.

Tooth anatomy


The tooth crown is a shell-like structure made of a hard, mineral based material called enamel.

Enamel rods

Calcium rods make up 96% of enamel composition, with 3% water and 1% protein framework surrounding each rod.


Dentin is a soft intermediary layer between the outer enamel and the pulp or heart of the tooth. It is about 70% calcium and 30% protein.


The pulp is soft tissue at the center of the tooth, and contains nerve endings and blood vessels.

Tooth decay

After having breached the enamel, acid damages dentin and eventually pulp in progressive stages of tooth decay.

Sugar and cavities

Foods related to cavity development contain dietary sugars like sucrose (table sugar), fructose (sugar found in fruit), and cooked starches like bread, crackers, or breakfast cereal.

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