Big Hopes for Little Teeth

What is the most common chronic disease in children? It’s tooth decay. Also known as cavities or caries, the condition is about five times more common than asthma and seven times more common than hay fever. Although tooth decay is preventable, it still affects nearly 46% of children in the U.S.

Caries develops when cavity-causing microbes feed on sugars from food and drinks and turn them into acids that eat away at teeth. Left untreated, tooth decay can put children at risk for chronic pain, impaired development, disfiguration, and social isolation. In severe cases, bacteria from a tooth infection can even travel to the brain and cause death.

Since NIDCR's founding in 1948, the institute and others’ efforts to tackle tooth decay have led to great improvements in the nation’s oral health. That work started with research demonstrating the efficacy of community water fluoridation and continues today with studies to tease apart the microbial underpinnings of tooth decay, test new treatments to halt caries, and develop novel technologies to enhance dental care. In part thanks to these scientific strides, the baby boomer generation — those born between 1946 and 1964 — will keep their teeth longer than any preceding generation. Untreated caries in preschool children is at a historic low.

Despite that remarkable progress, not all people have benefited equally. Caries disproportionately affects children who experience poverty, belong to certain racial and ethnic groups, or are affected by other social factors, according to NIDCR’s 2021 report Oral Health in America: Advances and Challenges. To address these disparities, NIDCR supports a variety of studies to identify and develop approaches to help children and families overcome barriers to receiving dental care and achieving good oral health.

“A healthy mouth in the child lays the foundation for oral and overall health and well-being for life,” said NIDCR Director Rena D’Souza, D.D.S., Ph.D., M.S. “Scientific and technological advances in recent decades have significantly expanded our ability to prevent and treat dental caries. We must ensure that all children, regardless of background, can benefit from this progress.”

The Birth of Preventative Dentistry

Shortly after opening a practice in Colorado Springs, Colorado, in 1901, a young dentist named Frederick McKay noticed that many of his patients’ teeth were mottled with honey- and chocolate-colored stains. Despite their appearance, the discolorations didn’t seem to affect the health of the teeth. On the contrary, and to Dr. McKay’s surprise, the stained teeth were unusually resistant to tooth decay. Several decades later, Dr. McKay and his colleagues discovered the cause of both the discoloration and cavity resistance: fluoride, a mineral naturally occurring at high levels in the town’s drinking water.

Building on Dr. McKay’s findings, subsequent research at the NIH by H. Trendley Dean, D.D.S., who became the first director of the National Institute of Dental Research (NIDR, now NIDCR), led to the idea of adding fluoride to a community’s water supply at physiologically safe levels to prevent tooth decay. In 1945, scientists put the idea to the test in a community trial sponsored by the U.S. Surgeon General and taken over by NIDR shortly after its inception in 1948. The 15-year project, which took place in Grand Rapids, Michigan, tracked the dental health of almost 30,000 children in the community. After just 11 years, NIDR announced astounding results — the rate of tooth decay among children born after fluoride’s introduction had dropped by more than 60%.

Over the past seven decades, extensive national and international research, including NIDCR-supported studies, have added to evidence that fluoride use for caries prevention is safe and effective. Today, over 200 million people in the U.S., or 73% of the population, have access to fluoridated drinking water, and almost every toothpaste on the market contains fluoride as its active ingredient. Little did Dr. McKay know that his observation would spark one of the greatest public health measures of the 20th century.

What Shapes Oral Health?

While the use of fluoride can help prevent tooth decay, it’s not a silver bullet. Some children still develop caries due to a complex interplay of environmental, behavioral, and biological factors. These can include limited access to fluoride, nutritious food, and dental and health services. Genetics, the oral microbiome, and social factors like socioeconomic status can also influence a child’s risk of getting cavities. Various NIDCR-supported studies are shedding light on the contributors to the disease.

“The environment starts shaping a child’s oral microbiome from the day of birth — even before one has teeth,” said Tamara McNealy, Ph.D., director of NIDCR’s Oral Microbiota and Bacterial Disease Program. “We need to understand how to establish a healthy microbiome from day one and how to maintain it in a holistic way. This knowledge will be really powerful for setting children up for a healthy childhood and adulthood.”

Recent NIDCR-supported research supports the idea that a child’s environment influences oral health early in life. Jin Xiao, D.D.S., Ph.D., and her colleagues at the University of Rochester discovered that preschool children with severe caries and their mothers had high levels of the decay-related oral fungus Candida albicans. Most of the mother-child pairs shared genetically related C. albicans strains, suggesting that the mothers had transmitted the fungus to their children. Another study found links between untreated maternal tooth decay starting in pregnancy and a child's risk of developing cavities by age 3. These findings highlight the importance of maternal health on children’s oral health and may inform the development of early interventions to set children down a path of better oral health.

University of Pennsylvania researchers found that saliva from toddlers with severe tooth decay harbored cavity-causing bacteria that could piggyback on fungi to form a “superorganism” that “walks” and “lunges” across tooth-like surfaces. The scientists hypothesize that these movements allow the bacterial-fungal assemblage to spread faster and farther than either organism alone, making them extra skilled at promoting tooth decay. The study, which was co-led by Hyun (Michel) Koo, D.D.S., Ph.D., may help researchers better understand how severe tooth decay develops in young children. It could also point to new approaches to prevent or treat the disease.

Arresting Tooth Decay

Current treatments for decay rely on restoration (fillings) and tooth extraction, which in severe cases in very young children can involve general anesthesia. Studies have shown that these interventions are costly, tooth decay often returns later, and anesthesia carries risks, especially for young children. Recent findings suggest there may be an alternative to the drill on the horizon.

A randomized clinical trial supported by NIDCR tested the effectiveness of silver diamine fluoride (SDF) for treating severe tooth decay in children ages 1 to 5. SDF is a liquid compound that is FDA-approved for dental sensitivity and is used off label to treat caries. It can be easily and painlessly swabbed onto cavities. Studies suggest that the silver in SDF kills cavity-causing microbes and helps stop destruction of the tooth, while the fluoride helps to rebuild and strengthen the tooth. Preliminary results from nearly 600 children showed that SDF was superior to a placebo in halting tooth decay. Final results from over 800 children will be available soon.

The trial was designed to meet FDA’s drug approval requirements for use of SDF as an intervention for cavities. FDA approval could lead to the product becoming more widely available; more acceptable among providers, patients, and parents; and more likely to be covered by insurance.

“This is really going to be a game changer. Since the approval of fluoride products such as toothpaste and mouth rinses for caries control, we haven’t had any products approved by the FDA for dental caries,” said lead investigator Margherita Fontana, D.D.S., Ph.D., of the University of Michigan. “SDF is one more option in our toolbox that we can offer people as treatment for cavities.”

Reaching Every Child

Although the nation’s oral health has vastly improved over the past 75 years, not every child has reaped the benefits. Oral health problems disproportionately affect Hispanic and non-Hispanic Black children and children from lower-income households. These differences, or disparities, arise in part from social determinants of health — conditions in which people are born, live, and work that influence their access to economic opportunities, education, health care, social support, clean air and water, and nutrition. About half of all children in the U.S. do not receive regular dental care because of these social, economic, and geographic obstacles.

To address disparities in childhood tooth decay, NIDCR-supported researchers are evaluating national and local oral health policies and working with caregivers, community organizations, and safety-net health care systems to investigate ways to help families overcome barriers to accessing evidence-based caries interventions. These studies are exploring the use of smartphone apps that provide monetary incentives for practicing healthy tooth brushing habits, community-based programs to help reduce sugar intake in Alaska Native communities, and strategies to reduce the stress of dental visits for children with autism spectrum disorders.

Emerging technologies are harnessing artificial intelligence (AI) to bring dentists to the patients. Dr. Xiao and her colleagues are working to develop an AI-powered smartphone app that screens for cavities in children by analyzing a photo of the problematic tooth. Parents can quickly secure a virtual dental visit and follow-up treatments upon detection. This could help lower the financial burden of dental visits and increase early detection and treatment of decay before it becomes severe.

In many cases, children have access to primary health care but not to dental care. Therefore, routine primary care visits present an opportunity for patients to receive preventive oral health screenings and referrals to dentists. In a 2023 Journal of the American Medical Association editorial, Dr. D’Souza and NIDCR Deputy Director Jennifer Webster-Cyriaque, D.D.S., Ph.D., put out a call for more research into the effects of these interventions on oral health.

One of the groups answering that call is a team at Case Western Reserve University led by Suchitra Nelson, Ph.D. They are testing ways to increase dental visits and reduce untreated caries among Medicaid-enrolled children attending well-child visits in pediatric offices. These strategies include training pediatric providers to convey oral health information to patients and caregivers, document patients’ oral health status in their electronic health records, and provide referrals to local dentists who accept Medicaid.

“Oral health research alone cannot fix dental caries disparities,” said Hiroko Iida, D.D.S., M.P.H., director of NIDCR’s Oral Health Disparities and Inequities Research Program. “We need to engage with communities and understand their values and beliefs to develop culturally appropriate and sustainable approaches so scientific advances can reach children who need them most.”

Related links:

• Report Reveals Striking Differences in Oral Health Care Across the U.S.
• Creepy Crawlies on the Teeth
• Equalizing Access to Dental Care
• A Safe Space in the Dental Clinic
• Conceptualization of Social Determinants of Health

References:

Arnold FA Jr. Grand Rapids fluoridation study; results pertaining to the eleventh year of fluoridation. Am J Public Health Nations Health. 1957 May;47(5):539-45. doi: 10.2105/ajph.47.5.539.

Xiao J, Moon Y, Li L, Rustchenko E, Wakabayashi H, Zhao X, et al. Candida albicans Carriage in Children with Severe Early Childhood Caries (S-ECC) and Maternal Relatedness. PLoS One. 2016 Oct 14;11(10):e0164242. doi:10.1371/
journal.pone.0164242.

Ren Z, Jeckel H, Simon-Soro A, Xiang Z, Liu Y, Cavalcanti IM, et al. Interkingdom assemblages in human saliva display group-level surface mobility and disease-promoting emergent functions. Proc Natl Acad Sci U S A. 2022 Oct 11;119(41):e2209699119. doi: 10.1073/pnas.2209699119. Epub 2022 Oct 3.

Fontana M, Khera, D, Levy, S, Echkert G, Katz B, Yanca E, et al. A randomized clinical trial to assess caries arrest by using silver diamine fluoride in U.S. children — interim findings. Pediatric Dentistry. 2024 Feb. (in press)

Al-Jallad N, Ly-Mapes O, Hao P, Ruan J, Ramesh A, Luo J, et al. Artificial intelligence-powered smartphone application, AICaries, improves at-home dental caries screening in children: Moderated and unmoderated usability test. PLOS Digit Health.2022;1(6):e0000046. doi: 10.1371/journal.pdig.0000046. Epub 2022 Jun 2.

Reddy MS, D'Souza RN, Webster-Cyriaque J. A Call for More Oral Health Research in Primary Care. JAMA. 2023 Nov 7;330(17):1629-1630. doi: 10.1001/jama.2023.22005.

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Reprint this article in your own publication or post to your website. NIDCR News articles are not copyrighted. Please acknowledge NIH's National Institute of Dental and Craniofacial Research as the source.

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