Purpose: The aims of this study were to determine the accuracy and repeatability of CBCT for assessing gingival thickness (GT) as compared to transgingival probing and to investigate the correlation between GT and labial bone defects.

Materials and methods: This cross-sectional study comprised 37 patients who underwent CBCT imaging. A total of 111 sites were examined, and measurements were obtained from the same points on selected index teeth. The GT was measured, and the presence of dehiscence and fenestration defects was evaluated on the CBCT scans. Transgingival probing was performed at the same points as those used on the scans. Intraexaminer reliability for clinical and radiographic measurements and interexaminer reliability for radiographic measurements were tested. Agreement between the measurement methods and the correlations between GT and labial bone defects were assessed using intraclass correlation coefficient (ICC) and chi-square test, respectively.

Results: The agreement between both measurement methods was excellent and statistically significant (ICC = 0.888; P < .001), with a bias of 0.04 (95% CI: 0.01 to 0.08). Significant differences in the occurrence of fenestration (P = .023) and dehiscence defects (P < .001) between the thin and thick gingival phenotypes were observed, and the defects were positively correlated with the thin gingival phenotype.

Conclusion: CBCT demonstrated high diagnostic accuracy for GT measurements, with minimal discrepancies from the transgingival method. The presence of dehiscence and fenestration defects was positively correlated with thin gingival phenotype.