Crown lengthening is a routine surgical procedure, which remodels the contour of the gum line. Cavities can decay the tooth to the point where a restoration is virtually impossible without this procedure. The procedure does not actually lengthen the crown, but rather lowers the gum line. Commonly, the procedure is used to expose a greater amount of tooth structure for the purpose of subsequently restoring the tooth with a crown. Sometimes a tooth is broken below the gum line. In this case, crown lengthening is very successful in exposing more of the tooth so that the dentist has more tooth structure to work with. Crown lengthening is also the treatment for a "gummy smile". This increases the size of the teeth by removing gingival tissue that is making the teeth appear smaller than they are. In most cases, there is nothing wrong with the teeth, each tooth just needs to be exposed more.