Melanin pigmentation and inflammation in human gingiva

The study was carried out to determine the distribution of melanin granules in different anatomical areas of the gingiva and to relate the density of melanin granules to the degree of gingival inflammation. Specimens including free and part of the attached gingiva were secured from the vestibular surfaces of the six maxillary or mandibular teeth of 21 Caucasian subjects during periodontal surgery. Serial histologic sections 5 to 6 mu thick were prepared and stained with Hematoxylin and Eosin or Masson-Fontana. Evaluation of the H & E stained sections disclosed that the number of melanophores and melanin granules in the epithelium and the inflammatory cells of the subepithelial connective tissue gradually decreased from the free gingival groove area to the free gingival crest and from the free gingival groove to the mucogingival junction. The density of melanophores in the vestibular epithelium showed a significant positive correlation (r = 0.38, P less than 0.00003) with the severity of inflammation (numbers of inflammatory cells) in the attached gingiva but not in the free gingiva (r = -0.033, P less than 0.2643). There was a positive significant correlation between the density of melanin granules of the vestibular epithelium and that of the adjacent connective tissue in both the free (r = 0.57, P less than 0.0003) and attached gingiva (r = 0.46, P less than 0.0003).