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An Update on Demineralization/ Remineralization

Course Number: 73

Epidemiology of Caries and the Role of Fluoride

The message we have been taught is caries is a disease of the past, and although the common perception is that kids no longer get much tooth decay, the most recent large-scale data continues to suggest that we have not eradicated the problem just yet. These data, from the 1999-2004 National Health and Nutrition Examination (NHANES) Survey, show that overall, dental caries in deciduous (baby) teeth of children ages 2 to 11 declined from the early 1970s until the mid-1990s. From the mid-1990s until the most recent survey, the trend has actually reversed: a small but significant increase in primary decay was found, with the trend being more severe in younger children.1 Separate from the NIDR Survey, the US Surgeon General's report in 2000 confirmed caries remains the number one childhood disease among 5-17 year-olds.2 Among this group, caries is 5X as prevalent as asthma and 7X as common as hay fever. These data highlight the ongoing need for fluoride therapy.

Chart showing prevalence of total dental caries and untreated dental caries in the United States.

Figure 1. Prevalence of Total Dental Caries and Untreated Dental Caries in Primary or Permanent Teeth among Youth Aged 2–19 Years, by Age: United States, 2015–2016.

1 Significant linear trend with increasing age. 2 Significantly different from youth aged 2–5 years. Source: NCHS, National Health and Nutrition Examination Survey, 2015–2016.

NOTES: Total dental caries include untreated and treated caries. Click here for data table for Figure 1.

Venn diagram showing caries possibilities

In addition to the levels of disease that we do see and treat, there is also a concern about the amount of caries that go untreated. National surveys in the United States have routinely reported the levels of untreated dental caries, in children ages 2-19 in the United States, during various time periods.

According to the most recent survey:

“A decrease was seen in the prevalence of total dental caries (from 50.0% to 45.8%) in youth from 2011–2012 through 2015–2016. However, this decline was not statistically significant. For untreated dental caries, the prevalence was 16.1% for 2011–2012, with the percentage increasing to 18.0% for 2013–2014, and then declining to 13.0% for 2015–2016.”

And then further: “For National Health and Nutrition Examination Survey (NHANES) period 2015–2016, the prevalence of total and untreated dental caries in primary or permanent teeth among youth aged 2–19 years was 45.8% and 13.0%, respectively. For both total and untreated caries, prevalence was lowest among those aged 2–5 years. The prevalence of total dental caries was highest for Hispanic youth compared with other race and Hispanic-origin groups. The prevalence of untreated dental caries was highest for non-Hispanic black youth. The prevalence of total and untreated dental caries decreased as family income levels increased. Youth in families with incomes greater than 300% of the federal poverty level had the lowest prevalence of both untreated and total dental caries. There was an observed decline in the prevalence of total caries in youth during the 6 years from 2011–2012 through 2015–2016; however, the trend was not statistically significant. The prevalence of untreated dental caries increased from 2011–2012 through 2013–2014, and then declined for 2015–2016.”3

Over the most recent time frame reported for adults (1999-2004), 26% of adults 20 to 64 were reported to have untreated decay.4 Unfortunately, no newer data are available.

A broad review of the epidemiology has been published.5 which concludes “Caries is a worldwide problem associated with plaque, microorganisms, and the intake of carbohydrates. The presence of fluoride in the oral environment attenuates the process.” While we have made a lot of progress with the use of fluoride, there is still more work to do.

Chart indicating the number of incipient lesions in the US is 1,000,000,000.

Examining secondary has been estimated approximately 50% of the amalgam restorations that need replacing are due to recurrent caries. You have heard it a thousand times... “My teeth are all filled; there is no room for more decay!” A filling, as we know, can be successfully replaced twice before a more permanent restoration is indicated. Again, the role of fluoride therapy here is clear.

And what about root surfaces? Kids are all grown up and out of the house; are Mom and Dad justified in using a non-fluoridated toothpaste? It has been estimated that by the age of 50 at least one-half of the population will have at least 1 root surface caries lesion. The ongoing need for fluoride treatment is not limited to specific age groups. All patients can benefit from appropriate fluoride therapy.

Photo showing dental caries risk.
Photo showing dental root caries risk.

Dental Caries Risks

The changes in caries distribution are important in understanding and planning for preventive approaches for all age groups throughout the world. Changes in the clinical management of the caries process and an emphasis on early treatment mean we now lack estimations for both non-operative and operative treatments. The understanding of the caries process, in terms of a dynamic continuum of demineralization and remineralization, means epidemiological studies will soon change in the level of caries information and detection. The visual-tactile examination using diagnostic criteria such as established by Radike6 may no longer be sufficient to collect caries data in light of changing technologies for early detection and the need to measure non-cavitated carious lesions. Pitts et al.7 discuss the current caries epidemiology with respect to an emphasis on diagnostic standards.