Cavities, also known as caries, are a physical defect in the tooth where the enamel has been eroded through to the dentin layer.
The erosion of the enamel layer of the tooth is caused by acid in the mouth produced by bacteria.
Fillings are used to repair cavities which have only reached the dentin layer. If left untreated, the tooth will continue to decay until the cavity reaches the pulp tissue. Once this occurs, a root canal is required to treat the tooth.
Regular brushing and flossing after meals and seeing your dentist on a regular basis for checkups will help keep the surfaces of your teeth clean and help prevent cavities from forming. Early detection of cavities will allow them to be repaired before more expensive root canals are necessary.