Melanin repigmentation after gingivectomy: a 5-year clinical and transmission electron microscopic study in humans.

The epithelium-melanin unit is formed by the melanocytes and keratinocytes. There is little information available about the behavior of melanocytes after surgical injury. Five white patients with comparable gingival pigmentation underwent gingivectomy to remove bandlike melanin pigmentations for cosmetic reasons. Biopsy specimens were taken from gingivectomy sites and healing areas 2, 3, 6, 7, 15, 50, and 180 days and 1.5, 3, and 5 years after the procedure. Transmission electron microscopic study revealed melanocytes in the process of migration and undergoing mitosis 6 and 7 days postoperatively. These cells exhibited, in the 15-day specimens, renewal of their dendritic processes and the four different stages of melanosome development. Keratinocytes were devoid of pigmented material until 50 days postoperatively. Clinically, the intensity of the pigmentation varied among the patients. Two reached baseline coloration 1.5 years postsurgery, while three returned to baseline coloration by 3 years postsurgery. Thus, gingival resective procedures, if performed solely for cosmetic reasons, offer no permanent results. (Int J Periodont Rest Dent 1993; 13:85-92.)