Tooth decay is a common disease that can affect all ages.  A cavity occurs when acid attacks your tooth.  Bacteria in saliva need sugar to produce this acid and thus people that have a more sugary diet tend to have a higher incidence of tooth decay. 

Fluoride in toothpaste and our water help to remineralize small defects in teeth in the enamel layer caused by a minor acid attack (called 'Incipient lesions' in a tooth).  Incipient lesions are found only in the enamel layer of a tooth and do not necessitate a filling being done.  However, once the acid penetrates into the second layer of the tooth (dentin), then a filling is necessary to pevent further penetration to the nerve of the tooth.   A cavity that reaches the nerve can trigger significant pain.  This compromised tooth at that point can only be saved with root canal treatment.

Early detection of decay is the best way to prevent penetration to the nerve of a tooth.  Early detection occurs during your routine dental exam.  If decay is detected, a filling appointment is scheduled as soon as possible.  Dental freeezing is used to anaesthetize the tooth and a conservative preparation is made to remove the decayed tooth material. The preparation is then filled and sealed with a white (composite) or silver (amalgam) filling material.