Many definitions of periodontitis have been used in the literature for population-based studies, but there is no accepted standard. In early epidemiologic studies, the two major periodontal diseases, gingivitis and periodontitis, were combined and considered to be a continuum. National United States surveys were conducted in 1960 to 1962, 1971 to 1974, 1981, 1985 to 1986, 1988 to 1994, and 1999 to 2000. The case definitions and protocols used in the six national surveys reflect a continuing evolution and improvement over time. Generally, the clinical diagnosis of periodontitis is based on measures of probing depth (PD), clinical attachment level (CAL), the radiographic pattern and extent of alveolar bone loss, gingival inflammation measured as bleeding on probing, or a combination of these measures. Several other patient characteristics are considered, and several factors, such as age, can affect measurements of PD and CAL. Accuracy and reproducibility of measurements of PD and CAL are important because case definitions for periodontitis are based largely on either or both measurements, and relatively small changes in these values can result in large changes in disease prevalence. The classification currently accepted by the American Academy of Periodontology (AAP) was devised by the 1999 International Workshop for a Classification of Periodontal Diseases and Conditions. However, in 2003 the Centers for Disease Control and Prevention and the AAP appointed a working group to develop further standardized clinical case definitions for population-based studies of periodontitis. This classification defines severe periodontitis and moderate periodontitis in terms of PD and CAL to enhance case definitions and further demonstrates the importance of thresholds of PD and CAL and the number of affected sites when determining prevalence.

This study estimated the prevalence, severity, and extent of periodontitis in the adult U.S. population, with data from the 2009 and 2010 National Health and Nutrition Examination Survey (NHANES) cycle. Estimates were derived from a sample of 3,742 adults aged 30 years and older, of the civilian non-institutionalized population, having 1 or more natural teeth. Attachment loss (AL) and probing depth (PD) were measured at 6 sites per tooth on all teeth (except the third molars). Over 47% of the sample, representing 64.7 million adults, had periodontitis, distributed as 8.7%, 30.0%, and 8.5% with mild, moderate, and severe periodontitis, respectively. For adults aged 65 years and older, 64% had either moderate or severe periodontitis. Eighty-six and 40.9% had 1 or more teeth with AL ≥ 3 mm and PD ≥ 4 mm, respectively. With respect to extent of disease, 56% and 18% of the adult population had 5% or more periodontal sites with ≥ 3 mm AL and ≥ 4 mm PD, respectively. Periodontitis was highest in men, Mexican Americans, adults with less than a high school education, adults below 100% Federal Poverty Levels (FPL), and current smokers. This survey has provided direct evidence for a high burden of periodontitis in the adult U.S. population.

This report describes prevalence, severity, and extent of periodontitis in the US adult population using combined data from the 2009–2010 and 2011–2012 cycles of the National Health and Nutrition Examination Survey (NHANES). Methods Estimates were derived for dentate adults 30 years and older from the civilian non-institutionalized population. Periodontitis was defined by combinations of clinical attachment loss (CAL) and periodontal probing depth (PPD) from six sites per tooth on all teeth, except third molars, using standard surveillance case definitions. For the first time in NHANES history, sufficient numbers of Non-Hispanic Asians were sampled in 2011–2012 to provide reliable estimates of their periodontitis prevalence. Results In 2009–2012, 46% of US adults representing 64.7 million people had periodontitis, with 8.9% having severe periodontitis. Overall, 3.8% of all periodontal sites (10.6% of all teeth) had PPD≥4 mm and 19.3% of sites (37.4% teeth) had CAL≥3 mm. Periodontitis prevalence was positively associated with increasing age and was higher among males. Periodontitis prevalence was highest in Hispanics (63.5%) and Non-Hispanic blacks (59.1%), followed by Non-Hispanic Asian Americans (50.0%), and lowest in Non-Hispanic whites (40.8%). Prevalence varied two-fold between the lowest and highest levels of socioeconomic status, whether defined by poverty or education. Conclusion(s) This study confirms a high prevalence of periodontitis in US adults aged 30 years and older. Prevalence was greater in Non-Hispanic Asians than Non-Hispanic whites, although lower than other minorities. The distribution provides valuable information for population-based action to prevent periodontitis in US adults.

Total periodontitis using the case definitions in this study should be based on the sum of mild, moderate, and severe periodontitis.