Aim and Objectives: To assess the presence or increase of micronucleus in buccal mucosa smears of tobacco users and compare the micronucleus staining by PAP and Feulgen stain.

Methods: The study was conducted on 500 subjects (tobacco users and non-users),  divided according to duration and form of tobacco use. Exfoliated buccal cells were obtained from each subjects, 2 slides were prepared, stained with PAP and Feulgen stain. Minimum 500 cells were examined from each slide and mean total number of MN and mean MN frequency was evaluated. Study Design: Cross sectional study.

Results: There was statistically significant difference (P<0.05) in the micronucleus assay of tobacco users as compared to non-users by PAP and Feulgen stain , where PAP stain was able to identify higher number of micronuclei. In tobacco users, the mean total number of micronucleus with PAP and Feulgen stain was 17.5±11.2 and 11.87±6.71 respectively. In non-users, the mean total number of micronucleus with PAP and Feulgen stain was 5.70±3.08 and 3.27±1.82 respectively. In users, the mean micronucleus frequency with PAP and Feulgen stain was 1.79±0.65 and 1.61±0.49 respectively. In non-users, the mean micronucleus frequency with PAP and Feulgen stain was 1.18±0.43 and 1.03±0.13 respectively. Duration and form of tobacco use also showed statistically significant difference with PAP stain.

Conclusions: All forms of tobacco can cause and increase micronuclei. Thus micronuclei assay can be used as a marker of genotoxicity.

Keywords: Micronucleus; Oral Cytology; PAP Stain; Feulgen Stain.