Background and aim: Increased rate of micronucleus in buccal mucosa cells and its correlation with carcinogenesis is worth consideration. Recently, occupation in dental laboratories has been proposed as a predisposing factor. Therefore, the present study aimed to evaluate the effect of occupational exposure on buccal mucosa cells of dental laboratory technicians.

Materials and methods: This historical-cohort study was conducted on 16 male dental laboratory technicians and 16 males were selected as the control group. All samples were matched according to age. The samples neither had any recent viral diseases nor were consumers of any specific medications. Cigarette smokers and alcoholics, individuals with risky occupations or with a history of radiotherapy were excluded. Buccal mucosa cells were sampled by use of a plastic spatula and were stained with Papanicolaou stain. Micronucleus frequency was evaluated under light microscope (400×). T-test was used for statistical analysis. Significance level was set at 0.05.

Results: Micronucleus frequency equaled 69±70 and 27±8.6 in case and control samples, respectively; which is 2.6 times higher in the case group. T-test showed that the difference in micronucleus frequency was significant between the two groups. (P<0.001)

Conclusions: the present study showed that the frequency of micronucleated cells in buccal mucosa of dental laboratory technicians is 2.6 times higher than that of the control subjects. Therefore, the mentioned occupation may increase the risk of induction of oral malignant transformations.