In order for a filling or a crown restoration to be placed properly, adequate tooth crown height above the gum line is required. In addition, adequate distance is needed between the restoration and underlying bone. Crown lengthening is a surgical procedure that recontours the gum tissue and the underlying bone surrounding one or more teeth so that a sufficient amount of healthy tooth is exposed.Crown lengthening is often used as part of a treatment plan for a tooth that is to be fitted with a crown. This procedure provides the necessary space between the supporting bone and crown, preventing the new crown from impinging upon and damaging the gum tissues and underlying bone. If a tooth is badly worn, decayed, or fractured below the gum line, crown lengthening surgical treatment provides the necessary access to more of the tooth so it can be properly restored. It should also provide enough tooth structure so the new restoration will not come loose in the future.