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Tobacco use is among the most important risk factors for a range of oral pathologies, including oral cancer, oral mucosal lesions, gingival recession, periodontal disease, and dental caries.1 All of the major forms of tobacco used—cigarettes, cigars, pipe tobacco, and smokeless tobacco—have oral care consequences, and have been shown to increase the risk for oral cancers. Evidence suggests that higher risks are associated with greater amounts of tobacco used and longer duration of use. These findings have been consistent across numerous cultures and countries.1 Although tobacco smoking and alcohol consumption are the two primary risk factors for oral cancer, smokeless tobacco is also a contributing factor.2
Two types of smokeless tobacco—snuff and chewing tobacco—are in common use. Snuff tobacco is cured and may be a dry powder, a moist powder, or fine-cut strips of tobacco leaf; a small amount is usually placed between the lip or cheek and gum. Chewing tobacco, either loose leaf or a flat compressed cake, is placed in the mouth and chewed, or held in place between the cheek and gum.3 Among the carcinogens in smokeless tobacco, the major contributors are the tobacco-specific N-nitrosamines (TSNA), formed during fermenting and curing.2 In the U.S., the primary users of smokeless tobacco are white adolescent and young adult males, Native Americans, and Alaskan Natives;1 approximately 19% of male high school students had already used smokeless tobacco by 1993.3
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Although there has been a consistent decline in cigarette smoking of approximately 50 percent in U.S. adults during the past few decades, there has been increased use of smokeless tobacco, believed to be a less harmful habit, with less risk of lung cancer or emphysema than with cigarette use.3 Nevertheless, prolonged use of smokeless tobacco is an important risk factor for oral squamous cell carcinoma.3,4 Oral mucosal lesions are common in smokeless tobacco users and may even develop with relatively limited use.1 Fortunately, the oral mucosa must undergo prolonged exposure to the carcinomatous agents in smokeless tobacco before cancer develops.3 Supporting evidence from one study showed that 78% of 128 smokeless tobacco users with oral carcinoma had used snuff or chewing tobacco for longer than 40 years, while only 1.6% had been users for less than 20 years.3 |
Professional baseball players, who are frequent users of snuff and chewing tobacco, were studied to determine the risk of oral lesions; 46.3% were found to have leukoplakia, a white mucosal lesion.3 The risk of leukoplakia increased with increased duration of use, increased amount of use, and recent use of smokeless tobacco.3
| Considerable evidence in the literature demonstrates an association between smokeless tobacco use and oral cancer. A North Carolina Study of 255 women with oral and pharyngeal cancer, and 502 controls identified a relative risk of 4.2 associated with snuff taking.2 Further evidence for a causative associationincluded the facts that cancer risks were greatest in the location of the mouth where snuff had been placed, and that risk increased with duration of use. One study reported that 80% of patients with oral cavity carcinoma developed their cancers in areas where the wad of tobacco was held.3 In comparison, among 882 patients who were not smokeless tobacco users, only 8% of oral cancers were in these areas.Another study demonstrated that former users of smokeless tobacco had a relative risk of 1.5 for developing soft tissue sarcoma compared to nonusers.2 Despite these findings, studies refuting this association also exist.2,4 |
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Regardless of its form, since tobacco use is the most clearly identified cause of oral cancers, cancer screening and tobacco cessation counseling by dental practitioners should be emphasized as an essential strategy in comprehensive tobacco control efforts.5 