Gingival phenotype assessment: a comparative study of a novel CBCT-based measurement technique and transgingival probing

BACKGROUND: This study aimed to evaluate the accuracy and clinical utility of a novel, non-invasive cone-beam computed tomography (CBCT)-based protocol for measuring gingival thickness in the maxillary anterior region, using transgingival probing (TGP) as the reference standard. METHODS: In this cross-sectional study, 39 periodontally healthy patients (24 males, 15 females; mean age 36 ± 12 years) were recruited. Gingival thickness was measured at 2 mm, 4 mm, and 6 mm apical to the gingival zenith on the facial aspect of maxillary anterior teeth (234 teeth, 702 sites) using both TGP and a CBCT protocol involving radiopaque resin markers. Method agreement was analyzed via Bland-Altman plots and Deming regression. Diagnostic performance of CBCT for classifying gingival phenotype was assessed. RESULTS: CBCT measurements showed a strong correlation with TGP (ρ > 0.98, p < 0.001). Deming regression indicated a constant systemic error, with CBCT underestimating thickness by approximately 0.04 mm (95% CI: -0.053 to -0.035), but no proportional error. Despite this minor bias, agreement was excellent (Kappa > 0.95). CBCT demonstrated 100% specificity and > 96% sensitivity for identifying thick phenotypes. No significant differences in gingival thickness were found between genders. CONCLUSION: The novel CBCT-based measurement protocol shows high agreement with gold standard. The identified constant error is clinically negligible, supporting its utility as a reliable, non-invasive method for assessing gingival thickness and phenotype, with potential for integration with digital impression technology.