Interdental Papilla Morphology in Relation to Periodontal Soft- and Hard-Tissue Dimensions in Young Adults: A Clinical and CBCT-Based Cross-Sectional Study

Background/Objectives: Interdental papilla morphology is an important component of anterior periodontal esthetics. This study aimed to characterize periodontal phenotype distribution in young adults and investigate the relationships between interdental papilla morphology and gingival and alveolar tissue dimensions in the maxillary central incisor region. Methods: A total of 238 maxillary central incisors from 119 periodontally healthy young adults were evaluated. Gingival thickness (GT) was assessed by probe transparency (PT) and CBCT, while buccal bone thickness (BT), keratinized tissue width (KTW), papilla height (PH), and interdental papilla fill status were recorded. Associations between papilla morphology and periodontal tissue dimensions and relationships among soft- and hard-tissue phenotype components were analyzed. Results: A thin periodontal phenotype predominated, identified in 54.6% of sites by CBCT-based assessment and 43.6% by PT. GT and BT were significantly greater in thick than thin phenotype groups (p < 0.001), while KTW showed a site-specific difference. Papilla fill status was not significantly associated with GT, BT, KTW, or PH (p > 0.05), and PH was comparable between phenotype groups. GT was positively correlated with corresponding buccal BT (ρ = 0.410 and 0.521; p < 0.001) and, more weakly, with KTW (ρ = 0.204 and 0.216; p < 0.05). Conclusions: In periodontally healthy young adults, papilla fill status was not associated with GT, BT, KTW, or PH, suggesting that papillary appearance may not directly reflect surrounding periodontal tissue dimensions. In contrast, the positive GT–BT relationship supports a structural link between the soft- and hard-tissue components of the periodontal phenotype.