Soft tissue CBCT for diagnosing and planning treatment of altered passive eruption. A cross-sectional study.

BACKGROUND: Treatment for excessive gingival display, commonly known as gummy smile, remains challenging. This cross-sectional study investigates the clinical use of soft tissue CBCT (ST-CBCT) to measure the hard and soft tissues in the dento-gingival unit to diagnose and plan treatment for excessive gingival display. MATERIALS AND METHODS: The dento-gingival complex of maxillary anterior teeth was investigated, including gingival thickness, alveolar bone thickness, and supracrestal tissue attachment. A detailed clinical treatment sequence of the therapeutic journey of a patient with altered passive eruption is presented to illustrate the clinical application of CBCT, from diagnosis to the final outcome, using Digital Smile Design. RESULTS: Thirty patients with altered passive eruption were evaluated. The mean distance from the gingival margin to the bone crest was 4.2 ± 1.1 mm. The mean gingival thickness was 1.1 ± 0.3 mm, and crestal labial bone thickness was 1.0 ± 0.4 mm. The majority presented thick gingiva (≥ 1 mm, 63.4%), and nearly half of all teeth (48%) showed thick crestal bone (≥ 1 mm). Male participants demonstrated a higher prevalence of thin crestal bone than female participants (66.7% vs 49.2%; P = 0.007). Contralateral teeth exhibited statistically significant differences in the distance from the cementoenamel junction to the bone crest, soft tissue thickness, and bone thickness. CONCLUSIONS: The dento-gingival unit presented inter- and intra-individual variability. Tomographic diagnosis, classification, and treatment planning of altered passive eruption should be conducted on a tooth-by-tooth basis for higher surgical precision and predictability, ultimately improving patient care. Soft tissue CBCT offers a comprehensive 3D overview of the soft and hard tissues in the dento-gingival unit.