Histomorphometric Evaluation of Gingival Phenotypic Characteristics: A Cross-Sectional Study

Objectives: This study aims to explore the histological dimensions of the gingiva and the alveolar mucosa and to evaluate their associations with gingival phenotypic parameters, including gingival thickness (GT), keratinized tissue width (KTW), and gingival transparency. Methods: Histological and clinical assessments were performed on 45 healthy volunteers. Gingival and mucosal tissue samples were collected from the mucogingival junction region of one maxillary central incisor. Histomorphometric analysis included measurements of gingival and mucosal thickness, epithelial thickness, connective tissue thickness, epithelial papilla length and density, and keratinization. Clinical parameters included KTW and probe visibility upon insertion into the gingival sulcus. Correlations were statistically analyzed between clinical and histological parameters. Results: Probe visibility showed no significant correlations with any assessed parameter. Histological gingival thickness strongly correlated with gingival connective tissue thickness, moderately with epithelial thickness and papilla length, and weakly with papilla density. Mucosal thickness was strongly associated with connective tissue thickness and moderately with keratinization, but not with other parameters. KTW exhibited weak correlations with epithelial thickness and papilla length. Conclusions: Variability in gingival and mucosal thickness is primarily determined by connective tissue thickness, with a smaller contribution from the epithelium. Increased thickness is associated with longer, sparser epithelial papillae and with a tendency toward higher keratinization. KTW is significantly associated with epithelial thickness and papilla length, underscoring its relevance in gingival phenotype characterization.