Ans. Tooth decay describes the condition where in under a variety of harsh conditions tooth breaks down leading to the formation of a cavity. It starts with a hole/opening in the enamel. If this is not treated, It progressively reaches the deeper sections of the tooth where the pulp and the nerves are causing the tooth to become sensitive to a variety of stimuli and variety of gum problems such as inflammation and swelling, pain, numbness and ultimately tooth loss.