Periodontal and dental considerations in clinical crown extension: a rational basis for treatment.

When the clinical crowns of teeth are dimensionally inadequate, esthetically and biologically acceptable restoration of these dental units is difficult. Often an acceptable restoration cannot be accomplished without first surgically increasing the length of the existing clinical crowns; therefore, successful management requires an understanding of both the dental and periodontal parameters of treatment. This report provides further insight into this interdependence by examining the effects of tooth form on the periodontal morphology and surgical treatment, while relating them to requirements for esthetically and biologically acceptable full-coverage dental restorations. This report also explains the role that restoration margin location and emergence profile play in the maintenance of periodontal and dental symbiosis. The effects of violation of the supracrestal gingivae by improper full-coverage restorations is also illustrated.