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Dental Amalgam Study

Study: Use of dental amalgam in fillings decreases 73% in 5 years

Aug. 30, 2023
After analyzing more than 1.3 million filling encounters in the US from 2017 to 2022, researchers found the rate of amalgam fillings has decreased from 21.5% to 5.7%. Learn more.
Elizabeth S. Leaver, Digital content manager

A study on the use of dental amalgam in fillings used in the US shows a decrease of up to 73% in in posterior teeth from 2017-2022, and that fewer than 6% of dental fillings in posterior teeth in 2022 were composed of dental amalgam—but that amalgam use can vary depending on population.

The Epic Research study analyzed 1,346,918 posterior tooth filling encounters in that five-year span to assess the rate of amalgam fillings compared to resin or composite fillings each year, concluding that the rate of amalgam fillings has decreased from 21.5% of fillings in 2017 to 5.7% of fillings in 2022. It also noted its use decreasing across all payers, among all age groups, and across both rural and urban areas since 2017, but that “patients with the highest social vulnerability are still most likely to receive amalgam fillings.”

Dental amalgam has been used since the 1830s, and since then hundreds of millions of people have had amalgam fillings. Concerns about exposure to mercury as well as its potential impact to the environment have prompted a ban on amalgam for restorations in a number of countries including Sweden, Norway, and Germany. The study notes that the US and other countries are following a “phasedown” approach with amalgam restorations as outlined in the Minamata Convention on Mercury, a global treaty to protect health and the environment from the effects of mercury.

You might also be interested in: Mercury and dental amalgam fillings: Pros and cons

Also noted during that time frame from 2017-2022 is the use of resin/composite restorations having increased from 79.9% in 2017 to 94.5% in 2022.

In groups with the highest social vulnerability—a score linked to key barriers blocking overall patient wellness as well as challenges during a natural disaster and public health emergencies, according to Danessa Sandmann, MPH, head of operations for Epic Research and study coauthor—the percentage of people who received amalgam fillings also decreased, but not by as much: 58% since 2017, which compares to a 73% decrease in the overall rate of amalgam fillings. The discrepancy owes in part to amalgam restorations’ better longevity than restorations using other materials, making amalgam potentially “preferential in in patient populations where future dental care follow-up is less assured,” according to the study.

According to Sandmann, the percentage decrease in amalgam fillings used on very young children is the smallest decrease researchers found.

“Even though patients ages 0-6 make up the smallest proportion of patients getting fillings, we were surprised to see that this age group had the smallest decrease in use of amalgam in the past five years,” Sandmann told DentistryIQ. “This was especially interesting given patients 0-6 are considered at high-risk for the effects of mercury, per the FDA.”

Patients aged 15-48 account for the majority of posterior tooth fillings and as such, represent the majority of patients with amalgam fillings in the general population. This age group also had the greatest decline over time in the proportion of fillings that used amalgam.

Overall, said Sandmann, "While we are encouraged by the overall decrease in the use of amalgam fillings, it is important to understand where disparities in amalgam use still exist to help target education and possible interventions where needed and our study helps accomplish that goal."

Access the full study: Mercury-containing amalgam fillings account for less than 6% of posterior tooth fillings in 2022