We often tend to neglect the black spot on tooth, which eventually hollows out the entire tooth. At this stage the tooth cavity is limited to the outermost layer that's enamel. Over a period of time, it enters dentin which is the second layer of tooth. At this stage, slight sensitivity to cold/hot may be experienced. After eroding the dentin, it enters the third layer, which is the pulp, and this is the time you experience shooting pain, can't sleep in the night. This is the time you visit dentist and undergo a root canal treatment and then a crown, 2-4 appointments minimum and around 5000 rs expenditure. Now you realise that a visit to a dentist few months back would have been better. The dentist would have simply removed a decay and cover your tooth cavity with a dental cement. Just 600-800 bucks. So my dear patients, don't wait for the dental pain and then seek treatment. Better, keep a watch on your teeth, visit dentist every 6 months for routine check up, your will save lot of time, energy and money!