Smokeless Tobacco – Ammunition against Dental Caries? A Microbial Study

Aims: The tobacco plant, Nicotiana tabacum, has been one of the major risk factors for oral cancer. However, the literature has endowed it as “holy herb” since the pre-Columbian era as being used for treating pain, poisonous bites, ulcers, nasal polyp. So we designed a study to elicit the anti-microbial property if any, in smokeless tobacco against Streptococcus mutans and also to study the relationship of growth inhibition efficacy of three forms of smokeless tobacco, namely, raw tobacco leaves, mishri and khaini.

Study Design: Cross-sectional, observational study.

Place and Duration of Study: Department of Oral Pathology and Microbiology, Vasantdada Patil Dental College and Hospital, Kavalapur, Sangli, Maharashtra, India, between December 2014 to February 2015.

Methodology: Twenty two ml of un-stimulated whole saliva was collected from each of five healthy subjects, with no habit of tobacco consumption in any form, zero DMFT index. The samples were collected in the morning, half an hour after tooth brushing and were stored at 4°C prior to processing. Extracts from three forms of smokeless tobacco namely raw tobacco leaves, mishri and khaini were evaluated. The tobacco extracts were prepared using saliva and ringer lactate which was previously sterilized. The antibacterial effect of tobacco extracts was evaluated by well-diffusion method using Brain Heart Infusion agar plates. The bacterial growth inhibition zones were measured after 24 hours incubation at 37°C. Ciprofloxacin was used as a positive control.

Results: All extracts exhibited an inhibitory effect on the growth of S. mutans, except mishri extract. The mean diameter of bacterial growth inhibition zones for khaini extracts against S. mutans was higher than those of raw tobacco leaf and mishri extracts. The differences in the inhibition zones were however not statistically significant (One way Anova, p > 0.05).

Conclusion: Amongst the three forms of tobacco extracts analyzed, khaini had the highest anti-microbial property against the growth of S. mutans as compared to raw tobacco leaves and mishri.