Evaluating Radiographic Measurements for Detecting Interdental Papilla: A Pilot Study

This pilot study aimed to (i) compare the diagnostic accuracy of the radiographic gingival embrasure surface area (SRE) with the vertical distance between the contact point and alveolar crest (CBC) and the inter-radicular horizontal distance (IHD), both used to predict black triangle (BT) presence and (ii) explore the association between patient-related factors, gingival phenotype and BT occurrence.

A retrospective analysis of 118 interdental papillae from 35 patients was performed using cone beam computed tomography and clinical photographs. Receiver operating characteristic (ROC) curves and Youden index were used to determine optimal thresholds for each parameter. Mixed-effects logistic regression identified factors associated with BT.

SRE demonstrated the highest diagnostic accuracy (area under the curve [AUC] = 0.98), with a sensitivity of 0.895 and a specificity of 0.984 at an optimal threshold of 5.04 mm². CBC showed an AUC of 0.89, with a sensitivity of 0.825 and a specificity of 0.770 at an optimal threshold of 4.94 mm. IHD exhibited lower performance (AUC = 0.63, sensitivity = 0.509, specificity = 0.721). Age (OR = 1.18; 95% CI: 1.03-1.36) was significantly associated with BT.

SRE outperforms linear distances (CBC and IHD) for detecting the presence of BTs. Age was also significantly associated with BT occurrence.

The surface area of the gingival embrasure provides a potentially more accurate and reliable radiographic indicator for predicting BTs, offering a valuable alternative to conventional linear measurements in clinical practice.