Cracks or chips of the enamel layer do not heal and damage to the enamel layer is permanent.
A broken or chipped tooth may or may not be painful but a sharp broken surface is likely to irritate or hurt the tongue and/or other soft tissue in the mouth. A dentist is able to repair this quickly and effectively (usually in a single visit) using material called composite and a technique known as acid-etching.
A broken tooth is more likely to be painful if the pulp (containing the nerve of the tooth) is damaged or the (innervated) dentine layer of the tooth is exposed. In this case the procedure carried out by the dentist may take more than one visit. If the dentine needs to be protected, a combined restoration as described above may be possible if the dentine is protected.
More extensive damage may necessitate removal of the dental pulp by root canal extirpation and filling followed by post and core crown restoration. This requires several visits and several weeks or even months to be completed.