Functional C/L surgery: Your dentist recommends dental crown lengthening to make a restorative procedure possible. Perhaps your tooth is decayed, broken below the gum line, or has insufficient tooth structure for a restoration, such as a crown or bridge. Crown lengthening adjusts the gum and bone level to expose more of the tooth (high and dry) so it can be properly restored.
Cosmetic C/L surgery: Excess gum (Gummy smile) and bone tissue is reshaped to expose more of the natural tooth. This can be done to one tooth to even up your gum-line, or to several teeth to expose a natural broad smile.