Tooth decay usually starts when the food particles are stuck to the tooth surface. The mouth normally has the inactive bacteriae. So whenever there is sticking of the food particles on the tooth surface, these bacteria will become active and act upon the food particles on the tooth surface. They ferment the food particals and liberate acids. The acid starts destroying the outer most layer ( Enamel ). At this stage the patient will not experience any kind of pain, because the enamel does not contain any nerves in it. If the tooth is not treated at this stage, the acids along with the bacteria will gradually go to the next layer, i.e., the dentine. Now onwards, the patient starts having the sensitivity in the tooth, because the dentine has a few nerves in it. Even at this stage tooth can be protected by using appropriate filling material. If proper care is not taken, the decay will spread to the next layer i.e., the pulp. Once the decay reaches the pulp, patients will have severe, shooting or throbbing or dull pain which is continuous. The pain increases when the patient lies down, because of increase in the pressure inside the tooth. At this stage the tooth is not fit for filling . So the options would be either removal of the tooth or root canal treatment by which the tooth can be saved.

If the decay is within the first 2 layers i.e, enamel and dentine, the decayed portion is removed by a special dental instrument and a proper shape is given to the cavity to hold the filling material.

If the decay has gone to the 3rd layer i.e., the pulp, irrespective of the pain, the filling is not advisable. Instead the tooth has to be removed (extaction) or root canal treatment (RCT) has to be done.

The extent of the decay, whether it is in the first layer or in the second layer or in the third layer can be assessed by the clinical symptoms and taking the X-Rays (Radiographs).

Removal of the tooth can be of one sitting treatment, whereas, RCT is about 4- 5 sittings treatment. The treatment involves the removal of infected nerves and blood vessels present within the tooth, cleaning and filling. Once the RCT is done, the tooth is dead or non vital and becomes very brittle. This brittle tooth may break on chewing hard substances. To prevent the fracture of the tooth, usually after RCT a cap/ crown is given to the tooth. There are different types of caps/crowns, which the patients can opt according to their convenience. eg., Metal caps, ceramic/porcelain caps.