Background: Smoking is associated with the number of teeth. The purpose of this study was to determine the relationship of number of teeth with smoking and smoking cessation.
Methods: Subjects included 547 males aged between 55 and 75 years. Oral examinations were conducted in 2005. Smoking status information was collected from questionnaire surveys conducted in 1990, 1995, 2000, and 2005. The relationship between having more than eight missing teeth and smoking status was estimated with adjusted odds ratio.
Results: Comparing with never smokers, odds ratios of having more than eight missing teeth among current and former smokers were 1.96 and 1.86, respectively. The odds ratios in those who had stopped smoking for <or=10 years was 3.02, and for those who had ceased smoking for 11-20 years was 2.66. In those who stopped smoking for 21 years or more, there was no increase in the odds ratio.
Conclusion: Smoking had a positive association with the number of missing teeth and smoking cessation is beneficial for maintaining teeth. The odds of having more than eight missing teeth in those who had never smoked was equal to that of individuals who reported that they had stopped smoking for 21 years or more.