The wide spread of information about the hazards of smoking has concentrated very much on lung cancer and respiratory disorders, and little on the effect of smoking on oral cancer and periodontal disease.
There is no guarantee that if a person does not smoke, he or she will not get oral cancer. Dentistry has seen many cases of oral cancer in people who have never smoked. However, the chance of oral cancer increases if a person smokes, and more so if the individual is also a very heavy drinker of alcohol. It has been suggested that alcohol acts as a cleansing agent in the mouth and strips the oral tissues of protective layer that makes them more susceptible to the carcinogenic action of the smoke. Alcohol, consumed in sufficient quantities may itself be a carcinogenic. In fact, many researchers believe it is one of the major causes of oral cancer. How much does smoking commit to oral cancer? Here's one bit of statistical evidence that is revealing. Of people that have recovered from cancer of the mouth, 40% of those who smoke develop second oral cancers, compared to 6 percent of those who do not smoke.
With regard to the effect of smoking on the conditions of the gums in general, there is a rise in temperature in the mouth from the direct heat of smoking that weakens the gums. The smoke also irritates the mouth tissues chemically, as well as causing circulatory problems. If the circulation is impaired, healing after treatment for periodontal disease (and other dental conditions) can be delayed or aborted.