Tooth decay begins when the enamel of your tooth breaks down, creating a small pocket (hole) in the tooth. It is quite common for tooth decay to go undetected particularly in areas that are less visible in the mirror or between the teeth.
Usually decay occurs from the build up of bacteria on the teeth that has accumulated from foods and liquids left in the mouth. Poor oral hygiene escalates the build up of bad bacteria.
The below illustration is a basic graph of how tooth decay may worsen if left untreated.
When detected early, Enamel or Dentin decay can often be resolved with filling. Filling material may consist of resin, ceramic, or dental amalgam.
Depending on how far dentin decay has occurred, advanced levels of dentin decay may require a dental crown.
Upon the third & fourth stage of the illustration below, where decay has reached the pulp of the tooth, root canal therapy (RCT) is required to help save the tooth. This involves removing the damaged pulp with the cavity being cleaned and filled. A dental crown is then placed over the affected tooth that appears natural and unnoticeable.
The latest stage pictured below is often the most common causes of tooth pain. Once infection has reached the tip of the tooth (connected to the bone), there is also risk of the area becoming infected. Swelling of the gum usually occurs at this stage, further attributing towards the pain.
Unfortunately with the final stage and in most severe cases when left untreated and gum disease advancing, the tooth may require extraction.
Good oral hygiene is the best form of preventing tooth decay. Early detection is part of they reason why regular dental visits (once every 6 months) are essential in the longevity of natural teeth.