Current smokers had higher fraction of teeth with apical periodontitis (AP) than never-smokers (0.13 vs. 0.10; P = 0.025), while fractions of endodontically treated teeth and endodontically treated teeth with AP did not differ significantly. When overall number of teeth was controlled for, smokers were 16.4 times more likely to have AP than a non-smokers (95% CI: 5.7-47.7; P < 0.001) and if a person was male, he was 3.1 times more likely to have AP than if the person was female (95% CI: 1.1-8.9; P = 0.039). The probability of AP increases with increase of age. Smokers will on average have two teeth with AP more than non-smokers, while controlling for gender, age and overall number of teeth.