Crown lengthening therapy aims to expose more tooth structure for restorative or aesthetic purposes. A 2010 review summarizes key aspects of the procedure, including maintaining at least 3mm of biological width and 1.5mm of ferrule length for improved force distribution and reduced attachment loss. Soft and hard tissue management is also discussed. Osseous resection may take 3-6 months to establish biological width, so impressions and final preparations should wait at least 6 months to allow for stable tissue healing.