Khảo sát mô học tăng sắc tố nướu

Abstract

Melanin deposition–related gingival hyperpigmentation is a common physiological variant that may markedly compromise smile esthetics. This study aimed to quantify melanocyte density in hyperpigmented gingival tissue and to investigate the association between the Dummett Oral Pigmentation Index (DOPI) and melanocyte count. A cross-sectional study was conducted on 40 patients aged ≥ 18 years old presenting with gingival hyperpigmentation (DOPI ≥ 1). 160 gingival biopsy specimens were collected to perform histopathological analysis, and DOPI scores were assessed using standardized clinical photographs. The mean gingival thickness was 1.28 ± 0.50mm. The mean melanocyte count was 8.72 ± 3.25 cells per specimen, with a total of 1,396 melanocytes identified. The distribution of DOPI scores was grade 1 (36.3%), grade 2 (27.5%), and grade 3 (36.3%). Melanocyte counts differed significantly among jaw segments and demonstrated a progressive increase with higher DOPI grades (p = 0.001). Multivariable regression analysis revealed that each one-grade increase in DOPI was associated with a 15% increase in melanocyte count (IRR = 1.15; 95% CI: 1.06 – 1.24; p = 0.001), whereas gingival thickness showed no significant association. Melanocyte density increases in proportion to the severity of gingival hyperpigmentation and exhibits significant variation across different jaw segments.