Tooth filling. And when is it required?

Hello mam... Tooth filling is usually done for cavitated tooth Tooth portion consists of Enamel(outermost portion),Dentine(inner layer), pulp( contains nerves and blood vessels)... When the cavity is in the superficial enamel layer patient can notice mild black discoloration on the tooth and does not have any symptoms.. when the cavity reaches dentin patient may have the symptoms of sensitivity and food lodgement.... Tooth filling can be done if the cavity is in the enamel and dentin zone....The cost of tooth filling varies from rs.800- rs.1200 depends on type of material used for filling If the patient does not fill the cavity then the cavity further progress and reaches innermost pulp layer and it causes symptoms of pain...In this stage filling does not work and you need to go for root canal treatment only....If you does not take care in this stage also then the infection progress to the root and cause severe infection around the apex of the tooth and it is medically called as abcess formation...