[Morphological study of melanocytes in infantile gingival epithelium. The distribution density of melanocytes].

In order to observe morphological features and distribution density of melanocytes in infantile gingival epithelium, 52 cases of clinically normal gingiva on 4-12 years old were examined by using sections prepared by paraffin dopa method and combined dopa-premelanin reaction and extended specimens prepared by dopa reaction and splitting method. The following information was obtained: 1) Melanocytes were observed among keratinocytes of the basal layer and especially abundant on the side of the epithelial peg, but rare on the tip of the epithelial peg. 2) Shapes of cell body of melanocytes were predominantly elliptical and spindle-type and their size was as large as or a little larger than the neighboring keratinocytes, with its nuclear portion remaining unstained and clear. 3) Dendritic processes were making complicated traveling while repeating branching and were extending to several neighboring cell. 4) Distribution density of melanocytes in infantile gingival epithelium was 813/mm2 as determined using extended specimens. Distribution density as determined in the ratio of basal cell count to melanocyte count was 40.7 for activated type melanocytes, and 27.3 for 'activated+inactivated' type melanocytes, respectively. 5) No difference in distribution density was noted by age, sex and site of collection. 6) The ratio of activated type to inactivated type melanocytes in infantile gingival epithelium was 2:1, the latter representing 32.6% of the whole.