The treatment for a tooth with an abscess is a root canal treatment. This is when the pulp and the infection are cleaned out of the root canal and then the space this creates inside the root is completely filled by the dentist.
It just depends on how bad the tooth is. Most of the time the dentist will do a root canal (which is not as bad as everyone says) and then they put a crown on top. If the tooth is in bad shape they will sometimes just pull the tooth.