The threeto four-decade lag between peak in smoking prevalence and subsequent peak in smoking-related mortality was a major factor affecting public awareness of the substantial health hazards of tobacco use in developed countries (Lopez et al., 1994). This factor may be applicable to periodontal disease if this disease is chronically affected by smoking epidemic. We searched the literature electronically and plotted the number of journal articles on association between smoking and periodontal disease with the trend in cigarette consumption (for example, in the USA) and expected trend in periodontal disease epidemic due to smoking by the year group (Fig. 1). Both peaks of expected trend of the disease and the number of journals stand closely in the 1990’.