Abstract Introduction and objectives: The objective of this study was to observe the evolution of genotoxicity (micronucleation, binucleation, and multinucleation) from normal to periodontally compromised gingival epithelium (gingivitis and periodontitis) and to compare the severity of the damage. Methods and material: 45 participants formed 3 different categories; a control group of 15 healthy subjects, 15 subjects with gingivitis and 15 with chronic periodontitis. Smears were collected from all the gingiva and stained with acridine orange stain. A total of 500 cells were evaluated under fluorescent microscopy for nuclear abnormalities such as micronuclei, binucleation and multinucleation. The statistical analysis used was one way ANOVA and posthoc Tukey test. Results and conclusion: A statistically significant difference was observed when the age of the 3 groups was compared (p = 0.002); the control group was younger than those with chronic periodontitis or gingivitis. With respect to genotoxic changes, the differences for binucleation (p = 0.002) and multinucleation (p < 0.001) were statistically significant thus suggesting advanced damage in the nucleus. Such changes in genotoxicity could be of help to a clinician in determining prognosis. © 2019 Sociedad Espa˜nola de Anatom´ıa Patol´ogica. Published by Elsevier Espa˜na, S.L.U. All rights reserved.