Tooth decay or caries is a disease of the hard dental tissue. During this process, microorganisms release acids that break down the enamel, dentin and pulp.
Teeth are constantly surrounded by a biofilm (plaque) that contains many microorganisms. Some of these release organic acids through their metabolism, which in turn can lead to a decrease of the pH value around the tooth. The decreased pH value dissolves minerals from the tooth, which gradually deteriorates.