Aims: The aim was to investigate the influence of smoking on longitudinal marginal bone loss and tooth loss in a prospective study over 20 years. In addition, the effect of cessation of smoking on bone loss and the interaction between smoking, plaque and marginal bone loss were evaluated.
Material and methods: A total of 507 dentate individuals from an epidemiological study were examined in 1970 and 1990. The clinical investigation included registration of number of remaining teeth and presence of plaque. The marginal bone level was determined by assessments on the proximal surfaces on the radiographs from 1970 and 1990. The marginal bone loss was defined as the difference in marginal bone level over 20 years. The subjects were interviewed about smoking habits. Stepwise multiple regression analyses were adopted to calculate the influence of the independent variables on longitudinal marginal bone loss and tooth loss.
Results: In 1970, 50.7% of the subjects were smokers, while the corresponding relative frequency in 1990 had decreased to 31.0%. Smoking was significantly correlated to an increased marginal bone loss over 20 years. Individuals who stopped smoking between 1970 and 1990 lost significantly less marginal bone during this period than those who declared that they smoked during the 20-year period. Smoking was not found to be significantly correlated to tooth loss over 20 years.
Conclusions: The results support the hypothesis that smoking is a significant risk factor of periodontal disease.