Restoring teeth following crown lengthening procedures.

Crown lengthening procedures are often necessary to successfully restore teeth that have been mutilated at or below the level of the bone crest. Forced eruption is preferred to surgical removal of supporting alveolar bone, since forced eruption preserves the biologic width, maintains esthetics, and at the same time exposes sound tooth structure for the placement of restorative margins. To properly construct a crown, the minimal distance from the alveolar crest to the coronal extent of sound tooth structure should be 4 mm. Before initiation of forced eruption, the restorability of the root after completion of the orthodontic phase must be considered. A technique is suggested to calculate the root-to-crown ratio that will be created after root extrusion with respect to the coronal level of sound tooth structure before treatment.