Melanocyte Response Following Depigmentation by Cryosurgery and Mucosal Excision: A Comparative Clinical and Histopathological Study

AIMS: The main aim of this study was to evaluate the melanocyte response following depigmentation by cryosurgery and mucosal excision at both clinical and histopathological levels during 6 months. SUBJECTS AND METHODS: A total of 15 individuals, aged 25–45 years with hyperpigmentation on the facial aspect of the gingiva present in the esthetic zone were included. A split-mouth approach was used, wherein one side received depigmentation by a scalpel and the other side received cryotherapy, with the choice of the therapy and side chosen by the spin of the coin. For determining the melanocyte assay, a small amount of gingival tissue that was excised was studied under a special staining technique, i.e., Masson–Fontana method for melanin, a histochemistry procedure which determines the activity of melanin both quantitatively and qualitatively. Clinical and histological observations for the intensity of pigmentation were recorded at baseline and 6 months after surgery. STATISTICAL ANALYSIS USED: Paired and unpaired t-test. Results: The mean value of the Dummett Oral Pigmentation Index (DOPI) was 2.44 ± 0.51 at baseline; following depigmentation with scalpel technique, the mean DOPI was 1.05 ± 0.23 at 6 months; and there was a statistically significant difference in the mean DOPI when compared with that of the baseline (P = 0.001). Following depigmentation with cryosurgery technique, the mean DOPI was 0.33 ± 0.48 at 6 months which also varied statistically significantly with that of the baseline (P = 0.001). The mean value of melanin histopathological count (MHC) was 95.53 ± 9.03 at baseline; following depigmentation with the scalpel technique, the mean DOPI was 89.49 ± 7.56 at 6 months, which was not statistically significant (P = 0.795). Following depigmentation with the cryosurgery technique, the mean MHC was 75.38 ± 5.63 at 6 months, which was not statistically significant (P = 0.285). CONCLUSIONS: The mean histologic count of the melanocytes, which accounts for the re-pigmentation process has shown low recurrence values in cryosurgery over the scalpel technique even though the difference was not statistically significant.