Crown lengthening procedure The procedure involves removing soft tissue and sometimes bone to increase the amount of tooth that is visible. A periodontist may perform the procedure on one tooth, several teeth, or the entire gum line. Dentists may perform crown lengthening procedures to: • address cosmetic concerns • expose cavities beneath the gum line • expose fractured areas of tooth • expose more tooth structure before they can fit a device such as a bridge The dentist will be careful to preserve enough gum to maintain the health of oral structures.