Full digital workflow for crown lengthening by using a single surgical guide.

A technique using a digital workflow for performing crown lengthening by using a free software program is presented to digitally design a single surgical guide. The technique consists of obtaining standard tessellation language (STL) files from intraoral scans from a digital design of the new tooth shape and from a cone beam computed tomography (CBCT) scan, after which Digital Imaging and Communications in Medicine (DICOM) files are converted to the STL format. These files are then superimposed and used for surgical planning of the crown-lengthening procedure. The main component of the surgical guide is a labial upper band representing the biological width measurement based on the predicted digitally designed future gingival margin position. Accordingly, the lower edge of the band indicates the level of the main marginal incision, whereas the top of the band indicates the level where the alveolar bone crest must be repositioned by alveolotomy during the surgical crown-lengthening procedure. By performing an adequate diagnosis of the potential restorative outcome, the new position of the gingival margin and the crown shape can be predicted, and whether osteoplasty is needed can be determined.