Cavities /Tooth decay refers a hole or small openings present on the surface of your teeth. Dentist usually refers this cavities as Dental Caries. This is the most common dental problem compare to any other dental issues. Depending on the location and type we can broadly divided cavities into 3 types. Pit and fissure Cavities Smooth surface Cavities Root cavity. Dentist usually refers cavity into class 1, Class 2,Class3, Class4,Class 5, Class 6 based on the type of the tooth affected and location of the surface involved. Initially there is only a mild discolouration -Black or brown or chalky white appearance present on the surface of the tooth( Enamel-outer layer of the tooth) .Many people are unaware of the cavities in this stage, because there is no sensitivity or pain present at this stage. Once the cavity enters into the middle layer of the tooth-Dentin, we can see an evident hole present on the tooth and food may accumulated in the tiny cavities often. people have sensitivity on cold and sweet items mostly. Some people neglected this early symptoms. Dentist will clean the infected portions of the tooth and prepare the cavity properly and fill with suitable tooth colour material. Commonly this procedure is known as dental filling. it is a simple and single visit procedure. If the decay enters into the inner most layer -pulp , people may feel pain and sensitivity to hot substances. It requires a root canal treatment at this stage. not only the crown(top) portion of the tooth but the roots also required cleaning at this stage. It may require 2–3 sittings. People may not aware cavity is present or not, that’s why regular dental check up is more important to identify at the early stage itself.