All of the major forms of tobacco used in the U.S. have oral health consequences. Cigarette smoking can lead to a variety of adverse oral effects, including gingival recession, impaired healing following periodontal therapy, oral cancer, mucosal lesions (e.g., oral leukoplakia, nicotine stomatitis), periodontal disease, and tooth staining. Use of smokeless tobacco is associated with increased risks of oral cancer and oral mucosal lesions (e.g., oral leukoplakia).Smokeless tobacco use also causes oral conditions such as gingival keratosis, tooth discoloration, halitosis, enamel erosion, gingival recession, alveolar bone damage, periodontal disease, coronal or root-surface dental caries due to sugars added to the product, and tooth loss.

In addition to its systemic effects, described previously, nicotine, especially that contained in nicotine replacement therapies, can have various local oral effects, including local burning sensation, throat irritation, dry lips, and mouth ulcers (depending on the formulation/method of administration); however, the local effects of nicotine replacement therapy are generally mild and self-limited Nicotine itself is not considered a direct carcinogen, but may act as a tumor promoter. A 2019 systematic review of the literature examined the specific effect of nicotine on gingival, periodontal ligament, and oral epithelial cells in in vitro models. The review found that nicotine found at levels in tobacco smoke, nicotine replacement therapy, and e-cigarettes was unlikely to be cytotoxic to oral tissues, while saliva levels with smokeless tobacco use may be potentially cytotoxic; however, data were limited and, in some cases, contradictory.

Because of the oral health implications of tobacco use, dental practices may provide a uniquely effective setting for tobacco use recognition, prevention, and cessation. Health-care professionals, including dental professionals, can help smokers quit by consistently identifying patients who smoke, advising them to quit, and offering them information about cessation treatment.