Latest research on smoking

Dec. 1, 2000
Heavy smokers (20 cigarettes or more each day) are two to three times more likely to have periodontitis.

Heavy smokers (20 cigarettes or more each day) are two to three times more likely to have periodontitis.

Trisha E. O`Hehir, RDH, BS

We know from experience that smoking or tobacco use affects oral tissues. Beyond the oral cavity, smoking-related diseases are responsible for 20 percent of all deaths in the United States. We can no longer ignore our role in providing smoking-cessation information to patients or referring them to established programs. The August issue of JADA provides a comprehensive list of information sources. Another good source is Valerie Kimbell`s article on smoking cessation for pregnant women in the September issue of RDH.

Looking just at periodontal disease, heavy smokers (20 cigarettes or more each day) are two to three times more likely to have periodontitis. Elderly smokers are six times more likely to have periodontitis; diabetic smokers, eight to nine times more likely; and young people who smoke are likely to have advanced periodontal disease. The likelihood of former smokers having periodontal disease fell between smokers and those who had never smoked.

The statistics also indicate that the more a person smokes, the more disease that individual will have. Tooth loss also is linked to smoking history, with heavier smoking resulting in more tooth loss.

Smoking severely restricts the host defense by suppressing antibody production and altering neutrophils so they can`t kill bacteria. This leads to higher numbers of subgingival bacteria in smokers than in nonsmokers.

The link between smoking and periodontal disease is nothing new to clinicians. You`ve seen it for years. The research now is catching up with what you`ve known all along. Here are a few of the latest findings:

(1) Nicotine adversely affects tissue-healing. In laboratory studies, nicotine interferes with fibroblast growth and attachment to dentin chips and glass surfaces. Fibroblasts grown on clean surfaces appear normal, evenly spaced, and parallel. Fibroblasts grown in the presence of various concentrations of nicotine show irregular growth patterns and cell alterations. It is as though the cells are searching for a spot on the dentin chip or glass that is not contaminated by nicotine. This also can be seen when the root surface is coated with endotoxin. If a cell culture is mechanically agitated, more nicotine-affected cells are removed form the surface than control cells.

(2) Smoking will increase alveolar bone loss in women with low spinal-bone densities. Evaluation of 134 women showed smoking and the number of offspring (parity) strongly correlated with alveolar bone loss. Smoking appears to exacerbate alveolar bone loss in women with low bone-density measurements of the lateral spine. We already know that periodontal bone loss is seen in cases of hyperparathyroidism. This may explain the association seen between parity and bone loss. During pregnancy, a functional hyperparathyroid state occurs. Bone loss associated with smoking may not be as easily reversed as pregnancy osteoporosis of the hip.

(3) "... Smoking may well be the major preventable risk factor for periodontitis in the United States." The National Health and Nutritional Examination Survey (NHANES) was conducted several times on large segments of the population. The most recent was conducted between 1988 and 1994, when nearly 40,000 people were interviewed at home, followed by medical and dental examinations in a mobile-examination center. Individuals ranged in age from one to 90 years old.

Evaluation of NHANES III data found that smoking may be responsible for more than half of all cases of periodontitis. Smokers accounted for 42 percent of periodontitis cases, with former smokers adding another 11 percent. Smokers made up 28 percent of the study group. In the U.S., it is estimated that $50 billion is spent on smoking-related diseases. Perhaps the costs of treating 8.1 million cases of periodontitis associated with smoking should be added to this estimate.

(4) Smoking interferes with healing after nonsurgical therapy. A retrospective study in a periodontal practice in Greece suggests that smokers with advanced periodontal disease should skip the nonsurgical phase and go right to surgery. This is based on the fact that smoking seriously impairs healing following nonsurgical therapy.

Out of a group of 35 smokers, 43 percent needed surgery following nonsurgical therapy. In a group of 35 nonsmokers, only 12 percent needed surgery. The author questions the need for extensive, time-consuming nonsurgical therapy if flap surgery is unavoidable. Several aspects need to be considered in deciding to forgo the nonsurgical phase of treatment: cost-benefit ratios, risks vs. benefits, possible successes and failures, complications, time, and fees charged. In-depth discussions between the patient and periodontist must occur.

(5) Smoking at a young age affects periodontal health. A group of 300 healthy young men, drafted into the Spanish Army, were examined for periodontal disease. They were asked to fill out a questionnaire about their oral-hygiene habits, dental visits, and smoking. All were under the age of 20. More than half were smokers (53 percent). Only 13 percent visited the dentist each year. Smokers had less plaque and bleeding than nonsmokers, but they had deeper pockets and more attachment loss. More disease was measured in those who had smoked five years or more.

(6) Among periodontally healthy subjects, heavy smokers are 18 times more likely to be infected by periodontal pathogens than nonsmokers. A group of 25 smokers and 25 nonsmokers with no signs of periodontal disease were compared. Subjects were between 21 and 35 years of age. DNA testing was performed on two sites in the mouths of each patient to determine the presence or absence of suspected periodontal pathogens.

A total of eight subjects - one nonsmoker and seven smokers - harbored at least one pathogen. All seven of the smokers were considered heavy smokers, with each having more than a five-pack-year history. Pack years are calculated by multiplying the number of packs smoked each day by the total number of years as a smoker. For example, a person who smokes one pack per day and has smoked five years has a pack-year score of five. Someone who smokes two packs each day and has smoked for 10 years has a pack-year score of 20.

Trisha E. O`Hehir, RDH, BS, is a senior consulting editor of RDH. She also is editor of Perio Reports, a newsletter for dental professionals that addresses periodontics. The Web site for Perio Reports is She can be reached by phone at (800) 374-4290 and by e-mail at [email protected].