Dentoalveolar surgery
Prevalence of Visible Third Molars in the United States Population: How Many Individuals Have Third Molars?

https://doi.org/10.1016/j.joms.2015.08.009Get rights and content

Purpose

To determine the prevalence of third molars in the US population and to report the differences in prevalence of visible third molars in the most recent National Health and Nutrition Examination Survey (NHANES) population of 2011 through 2012 by participant, jaw, and demographics.

Materials and Methods

The number of visible third molars in the NHANES data was assessed in nonclinical settings by trained, calibrated dental hygienists by decade of age beginning in the 20- to 29-year-old cohort through the 70- to 79-year-old cohort. Cross-sectional analyses of third molar data were conducted by the authors from the NHANES databases of 2001 through 2002, 2009 through 2010, and 2011 through 2012 to compare data for similarity of outcomes on third molar prevalence in the US population. Outcomes on third molar prevalence also were assessed from the NHANES of 2011 through 2012 by participant, jaw, and demographics: gender, race or ethnicity (Caucasian, African American, other), and education (less than high school, high school graduate, some college, college graduate).

Results

Data on the mean number of third molars from NHANES of 2001 through 2002, 2009 through 2010, and 2011 through 2012 were similar. The number of visible third molars in the NHANES of 2011 through 2012 decreased progressively from a mean of 1.48 in the 20- to 29-year-old cohort to 0.81 in the 60- to 69-year-old cohort, No visible third molars were observed in 47% of the 20- to 29-year-old cohort compared with 53% in the 50- to 59-year-old cohort. Participants who were male, non-Caucasian, and had less than a high school education were more likely to have a visible third molar in all age cohorts. No data were collected by NHANES examiners to determine why third molars were absent.

Conclusion

Third molar prevalence did not appear to differ in the US population during the first decade of the 21st century. Numbers of visible third molars, prevalent in young adults, decreased progressively through each successive age cohort. Demographic differences exist for prevalence of third molars in the US population.

Section snippets

Materials and Methods

Trained, calibrated dental hygienists obtained the NHANES data in nonclinical settings. The authors' cross-sectional analyses of NHANES data included all participants examined in the NHANES for 2001 through 2002, 2009 through 2010, and 2011 through 2012. Data were available on the presence or absence of visible third molars. A visible third molar was a tooth with any anatomic component visible, defined in the NHANES surveyor's manual as “any part of the tooth projects through the gum.”3 The

Results

Demographic characteristics of participants studied in the NHANESs of 2001 through 2002, 2009 through 2010, and 2011 through 2012 were similar during the decade (Table 1). Differences appeared to mimic changes in the US population within that time frame. For example, larger numbers of non-white participants were sampled in the NHANES of 2011 through 2012 compared with 2001 through 2002 (64 vs 48%, respectively). Education levels were higher for participants in the NHANES of 2011 through 2012

Discussion

The data from NHANESs conducted during the first decade of the 21st century suggest that the prevalence of visible third molars has changed little for the US population, as assessed by cross-sectional analyses by 10-year age cohorts. Although participants within each 2-year survey were not the same and were not followed over time, clinical patterns of care and the public's attitudes and preferences for treatment of third molars seem to have remained the same in this decade. However, in each

Acknowledgments

The authors recognize and appreciate the support for this project from the Departments of Oral and Maxillofacial Surgery and Periodontal Medicine, University of North Carolina.

References (6)

There are more references available in the full text version of this article.

Cited by (21)

  • Associations between aging and second molar diseases in patients having adjacent impacted third molar extraction

    2021, Journal of the Formosan Medical Association
    Citation Excerpt :

    Another interesting finding in the current study is that a much higher percentage of female patients had iLM3 extracted than male patients in this cohort population, while male patients had higher risks of having dental caries and pulpal diseases on the adjacent LM2 postoperatively. Our explanation is that perhaps women tend to access health care system more and use health care services more, which is similar to the finding in another third molar study using the U.S. population database (NHANES).28 Overall, our data showed that the age of the patient having iLM3 extracted was independently associated with different LM2 sequelae.

  • Wisdom teeth, periodontal disease, and C-reactive protein in US adults

    2020, Public Health
    Citation Excerpt :

    Until now, only one US national study reported on the population prevalence of visible third molars, also using NHANES data.30 In that study, based on the NHANES 2011–2012, Magraw and colleagues reported unweighted M3 prevalences of 50% and 47% among US adults aged 30–39 years old and 50–59 years old, respectively, retaining M3.30 Our findings were weighted using the NHANES sample weights and show somewhat lower prevalence in these age groups.

  • Age of patient at the extraction of the third molar

    2018, International Journal of Oral and Maxillofacial Surgery
    Citation Excerpt :

    When only the youngest cohorts of our investigation are observed, a similar predominance in females as those reported in earlier studies from surgical units emerges. Findings of female predominance related to age are also found in the epidemiological study conducted by Magraw et al.4, in which men were more likely than women to have more third molars in all age groups up to the age of 70 years and thus, we can indirectly estimate that extractions were more likely in women than in men. However, there were major differences in the origin or background of the subjects between our study and the U.S. study.

  • Signs of disease occur in the majority of third molars in an adult population

    2017, International Journal of Oral and Maxillofacial Surgery
  • Contrasting Patterns for Missing Third Molars in the United States and Sweden

    2017, Journal of Oral and Maxillofacial Surgery
    Citation Excerpt :

    Although the present data are the only population data on the prevalence of third molars from developed countries, the data represents population samples several decades apart in time. Data from the United States on third molars available since 2000 suggest that treatment patterns have been similar since the turn of the century.2 However, no comparable published Scandinavia data are available for third molar treatment over time.

View all citing articles on Scopus

Conflict of Interest Disclosures: None of the authors reported any disclosures.

View full text