Smokeless Tobacco Use as a Risk Factor for Periodontal Disease

Periodontal disease is one of the leading causes of tooth loss, particularly among older individuals (1–6). Although dental plaque-associated microorganisms are the primary etiologic agents of periodontal diseases, several other factors such as local, genetic, systemic, and environmental factors play an important role in determining the susceptibility of individuals to periodontal diseases. Tobacco smoking is one of the most important environmental risk factors for periodontal diseases. Large numbers of studies have been conducted to understand the role of smoking in the etiology of periodontal diseases and the available data show that smoking is associated with increased prevalence and severity of periodontal disease, which may be due to the adverse effects of tobacco smoke on the physiology, immunology, and microbiology of the oral environment. Unlike smoking, the role of oral smokeless tobacco (SLT) in the etiology of periodontal disease has received considerably less attention. Although traditionally, oral SLT consumption has been associated with oral malignant and potentially malignant lesions, emerging data suggest that these habits may be associated with poor periodontal health also. Besides some case reports mentioning periodontal changes associated with oral SLT habits (7), initial studies conducted in the US have shown that oral SLT habits are associated with increased incidence of gingival recession (8–11). Studies conducted in Sweden also have shown that the consumption of moist snuff, an oral SLT product, is associated with increased prevalence of gingival recession (12–14). However, some studies conducted in the US and Sweden have failed to show any association between SLT habits and periodontal changes such as gingival recession, attachment loss, or bone loss (15–18). Unlike the studies among the Swedish and US populations, studies conducted among Asian populations have shown that oral SLT habits are associated with destructive periodontal disease. Studies conducted in India have reported that oral SLT users tend to have higher scores and risk for periodontal disease (19– 22). Similar results were reported among SLT users in Bangladesh and Thailand also (23, 24). A study based on National Health and Nutrition Examination Survey III data conducted in the US also showed strong association between oral SLT use and severe active periodontal disease (25). Very few studies have reported on the pattern of periodontal destruction among oral SLT users. A study on the patterns of tooth loss among tobacco users in central India showed that mandibular tooth loss was more among oral SLT users suggesting that the deleterious effects of SLT use is manifested more in mandibular teeth (26). Studies reporting the occurrence of gingival recession among oral SLT users have reported that these occurred at sites adjacent to mucosal lesions suggesting that the recession was a result of long-term injury to the gingival tissues from the SLT product (8, 10, 13, 14). Oral SLT users in a central Indian population were shown to have an increase in prevalence and severity of recession and attachment loss at mandibular teeth, buccal surfaces, anterior teeth, and molars-the surfaces most likely to have prolonged exposure to SLT product due to retention of the SLT product at the mandibular buccal or anterior labial vestibule (21). Oral SLT consumption in various forms is highly prevalent among all populations, particularly in the Asian countries (27– 35), and a wide variety of SLT products are available worldwide (36, 37). The most common SLT products available in the US include chewing tobacco and snuff (moist and dry), and in Sweden, the most common product is snus. In Asian countries, such as India and Bangladesh, a myriad of SLT products are available such as betel quid with tobacco, zarda (prepared by boiling tobacco leaves with water and slaked lime), gutka (mixture of powdered tobacco, areca nut, slaked lime, and catechu), mawa (areca nut, tobacco, and slaked lime), and khaini (tobacco with slaked lime). Although oral SLT habits are common among all populations, strong associations between SLT habits and destructive periodontal disease has been observed mainly among Asian populations, whereas a systematic review of studies testing the association between SLT habits and periodontal disease conducted in Sweden and the US suggested that SLT habits may not be related to periodontal diseases (38). Such contradictory observations may be due to several factors such as differences in the trends of oral SLT practices and the type of SLT products used by the respective populations.