At a glance
This page provides an overview of the survey used for the report, along with clarifying definitions on the data sources utilized by the authors. It also highlights the specific populations that were studied and outlines the analysis used for this report.
Data Sources
The National Health and Nutrition Examination Survey (NHANES) is a cross-sectional survey designed to monitor the health and nutritional status of the resident, civilian, and noninstitutionalized U.S. population. CDC's National Center for Health Statistics (NCHS) releases data in 2-year cycles for public use.
During the 2019–2020 cycle, NCHS interrupted data collection in March 2020 due to the COVID-19 pandemic. As a result, the partially completed 2019–2020 cycle was not nationally representative. NCHS combined these data with the 2017–2018 data and adjusted sampling parameters, including primary sampling units and weights, to create the nationally representative 2017–March 2020 prepandemic data files. More detailed information about the methods used to construct the combined data and analytic guidance on how to use the files are presented in an NCHS report.1
Data Definitions
As in previous surveillance reports using NHANES,234 this report presents oral health data collected by trained dentists who completed oral health assessments in mobile examination centers (MEC) using a standard protocol and detection criteria. All dental measures of permanent teeth are based on 28 teeth, excluding third molars. All prevalence estimates except for edentulism are for participants with one or more teeth (dentate). Edentulism is defined as having lost all permanent teeth.
As in previous surveillance reports, caries lesions were detected at the cavitated level. This information was used to calculate the decayed and filled teeth index in primary teeth (dft) and the decayed, missing, and filled index in permanent teeth (DMFT).3
We defined the prevalence of untreated dental caries, or tooth decay, as the proportion of dentate survey participants who had one or more decayed teeth.3 Consistent with the 2019 Oral Health Surveillance Report, the prevalence of untreated tooth decay is reported in primary teeth for children aged 2–8 years and in permanent teeth for those aged 6 years or older. For children aged 6–9 years, we also report the prevalence of untreated tooth decay in primary and permanent teeth.
The severity of dental caries among children, adolescents, and adults younger than 65 years is reported for those with dental caries. Measures for primary teeth are reported as the mean number of decayed and filled teeth among those having at least one decayed or filled tooth. Measures for permanent teeth are reported as the mean number of decayed, missing, and filled teeth among those having at least one decayed, missing, or filled tooth. We also report severity estimates with and without missing teeth among adults because not all missing teeth may have been a direct consequence of dental caries. Among adults, missing teeth is labeled as "missing due to disease." Dental caries severity is reported for all dentate adults aged 65 years or older.
Study Population
As in previous surveillance reports,234 we used the following age groups for our analysis: children aged 2–5 years and 6–8 years for primary teeth; children and adolescents aged 6–11 years and 12–19 years for permanent teeth; adults aged 20–34, 35–49, and 50–64 years; and older adults aged 65–74 years and 75 years or older.
All estimates were age-adjusted to the U.S. 2000 standard population to control for differences in age distribution.5 For adjustment, we used single years of age for children and adolescents and 5-year age groups, with the maximum age group set to 80 years or older, for adults.
We also used the same sociodemographic characteristics and categories as in previous surveillance reports.234 We analyzed the data according to race and ethnicity, family poverty status based on the federal poverty level (FPL), educational attainment, and cigarette smoking status.
Information on self-reported race or ethnicity was classified into three categories: non-Hispanic White, non-Hispanic Black, and Mexican American. We report estimates for Mexican American survey respondents only, instead of for all Hispanics, because this group has data that are comparable with previous reports.
Poverty status was classified as high if family income was below 100% of the FPL, middle if 100% or higher but below 200% of the FPL, or low if 200% or higher of the FPL. Findings are also presented for high and middle poverty status combined.
Educational attainment was classified as less than high school, high school graduate or equivalent, and more than high school.
Cigarette smoking status was classified into three categories: current smoker, former smoker, and never smoked. Current smokers were defined as respondents who reported having smoked at least 100 cigarettes during their lifetime and currently smoking cigarettes every day or some days. Former smokers were defined as respondents who reported having smoked at least 100 cigarettes during their lifetime but not currently smoking. Never smokers were defined as respondents who reported having smoked fewer than 100 cigarettes during their lifetime.
When comparing outcomes among different categories within the same sociodemographic characteristic, we used the same reference categories as previous surveillance reports. The reference category for sex was male; for race or ethnicity, non-Hispanic White; for poverty status, 200% or higher of the FPL; for educational attainment, more than high school; and for smoking status, never smoked.
Data Analysis
Within each characteristic, we conducted t-tests to evaluate statistical differences between each category and the reference group, as done in previous surveillance reports.234 For example, a test for poverty status used 200% or higher of the FPL as the reference group. For race and ethnicity, non-Hispanic White survey participants were the reference group.
All statistical analyses were performed using SUDAAN software Version 11.0.3 (RTI International, Research Triangle Park, North Carolina) and SAS software Version 9.6 (SAS Institute Inc., Cary, North Carolina) to account for the complex survey design. We used sampling weights corresponding to MEC participants. We present age-adjusted estimates and standard errors overall and stratified by characteristics.
We used P <0.05 to report statistically significant differences. Following NCHS recommendations, estimates based on denominator sample size less than 30 or with higher than 30% relative standard errors were considered unreliable and not displayed in the tables.6
Our results are presented in 18 tables. Important results are presented in the Selected Findings section.
- Akinbami LJ, Chen T-C, Davy O, et al. National Health and Nutrition Examination Survey, 2017–March 2020 prepandemic file: sample design, estimation, and analytic guidelines. Vital Health Stat 2. 2022;190.
- Centers for Disease Control and Prevention. Oral Health Surveillance Report: Trends in Dental Caries and Sealants, Tooth Retention, and Edentulism, United States, 1999–2004 to 2011–2016. U.S. Dept of Health and Human Services; 2019.
- Beltrán-Aguilar ED, Barker LK, Canto MT, et al. Surveillance for dental caries, dental sealants, tooth retention, edentulism, and enamel fluorosis — United States, 1988–1994 and 1999–2002. MMWR Surveill Summ. 2005;54(3):1–43.
- Dye BA, Tan S, Smith V, et al. Trends in oral health status: United States, 1988–1994 and 1999–2004. Vital Health Stat 11. 2007;248:1–92.
- Klein RJ, Schoenborn CA. Age adjustment using the 2000 projected US population. Healthy People 2010 Stat Notes. 2001;20.
- Parker JD, Talih M, Malec DJ, et al. National Center for Health Statistics data presentation standards for proportions. Vital Health Stat 2. 2017;175.