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

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.

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.

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.

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.