Addressing Patient Concerns About Dental Materials
Common product components are under tough scrutiny
With the rise of social media and the increase in the speed of communication today, patients are likely to encounter health information that concerns them and comes from a range of sources. Many will turn to their oral health care providers for answers.
In addition to radiation, which was discussed in the February issue of Inside Dentistry, the issues generating the most “buzz” and patient questions these days are the antibacterial chemical triclosan, bisphenol A (BPA), and mercury in dental amalgam. Practitioners who are able to fill in knowledge gaps—and correct misinformation—can help patients make informed choices about their dental care.
Triclosan
What Is It?
Triclosan is widely used in personal products such as soaps, toothpaste, mouthwashes, and deodorants. It is described by the US Food & Drug Administration (FDA) as “an ingredient added to many consumer products to reduce or prevent bacterial contamination.”1 It also used commercially in pesticides.
The Basis of the Controversy
Triclosan was introduced to the marketplace in 1972 to prevent bacterial infections in hospitals and has become a recommended regimen for the decolonization of patients whose skin is carrying methicillin-resistant Staphylococcus aureus.2 Due in part to consumer demand for antibacterial products, it is now found in everyday bath and oral health care products and other types of consumer goods, including kitchen utensils, toys, bedding, socks, and trash bags.3 This raises concerns that overuse could cause strains of bacteria to develop that are resistant to antibacterials in much the same way that antibiotic-resistant bacterial strains are emerging.4 Further, an article in the journal Clinical Infectious Diseases found that antibacterial soaps did not prevent more illness or reduce the amount of bacteria on hands when compared with plain soap.5
Other scientific findings raise additional issues, including the potential impact on the immune and muscular systems. According to a University of Michigan School of Public Health study, children who are overexposed to antibacterial soaps containing triclosan are more likely to be diagnosed with hay fever or allergies.6 Another study from researchers at the University of California at Davis and the University of Colorado reported that triclosan “hinders muscle contractions at a cellular level, slows swimming in fish, and reduces muscular strength in mice.”7 The investigators also found that triclosan impairs heart and skeletal muscle contractility in animal subjects, but noted that these findings cannot be translated to humans without further study.
The Official Position
The FDA has a mixed response to the question of whether triclosan provides a benefit in consumer products. In 1997, the FDA reviewed extensive effectiveness data on triclosan in one brand of toothpaste, and concluded that triclosan was effective in preventing gingivitis. The agency notes that similar data are not available for antibacterial soaps and body washes containing triclosan, and at this time there is no evidence of a benefit of these products over washing with regular soap.
The FDA continues to monitor the safety profile of triclosan, but the agency’s official position is that “triclosan is not currently known to be hazardous to humans.”1 After this position was established, however, animal studies were published that show that triclosan alters hormone regulation; the FDA notes that these results “merit further review.”1 The agency concludes, “In light of these studies, FDA is engaged in an ongoing scientific and regulatory review of this ingredient. FDA does not have sufficient safety evidence to recommend changing consumer use of products that contain triclosan at this time.”1
BPA
What Is It?
BPA is a chemical that is often characterized as an endocrine disruptor; it has a chemical structure that allows it to act like a weak estrogen hormone.8 It is used to produce the polycarbonate plastics and epoxy resins found in a wide variety of products. Polycarbonate plastics are used for goods such as safety equipment, compact discs, medical devices, and food and drink packaging, including, until recently, infant bottles. Epoxy resins are used in some dental sealants and composites as well as in lacquers that coat metal products, including bottle tops, food cans, and water pipes.9 BPA is also found as an easily absorbed free monomer in thermal paper, such as that used in some cash register receipts and tickets.10
The Basis of the Controversy
Concerns are based on numerous studies suggesting a connection to adult illnesses and disorders, including obesity, cardiovascular disease, diabetes, and fertility problems, as well as problems with children’s behavior.8,11 A survey of almost 1,500 adults aged 18 to 74 years in the United States associated higher BPA levels in the urine with a greater probability of being diagnosed with diabetes, cardiovascular disease, or liver enzyme abnormalities. A follow-up to this study noted an increased risk of overall obesity and belly fat in those with higher BPA levels.8
Studies have also showed that BPA can have adverse effects in pediatric patients. A study led by Maserejian compared exposure to bis-GMA–based dental composite restorations with exposure to amalgam and found an association between composite restorations with impaired psychosocial function in children; no adverse psychosocial outcomes were observed with either greater urethane dimethacrylate-based compomer or amalgam treatment levels.11 Obesity concerns were raised mainly by a New York University study showing that children with the highest levels of BPA in their urine also had the highest rates of obesity.12
The Official Position
The FDA and the American Dental Association (ADA) have reassessed their original positions on BPA in light of new evidence. Although the FDA had ruled in 2008 that the chemical was safe for all uses, it introduced steps to reduce exposure for children in 2010 and outright banned its use in baby bottles and sippy cups in July 2012, an action taken in response to an American Chemistry Council petition.13,14 The US Department of Health and Human Services (HHS) explained that although “BPA is not proven to harm children or adults, these newer studies have led federal health officials to express some concern about the safety of BPA.”13 The HHS position includes a call for more research to better understand the potential human health effects of BPA exposure, especially on young children.13
The ADA has previously called concern about potential BPA exposure from dental composites or sealants “unwarranted at this time,” but as of January 30, 2013, it has taken the topic of BPA in dental materials under review.15
Mercury
What Is It?
The least expensive of filling materials, dental amalgam has been used for more than 150 years. It is a mixture of metals comprising liquid mercury and a powdered alloy composed of silver, tin, and copper. Approximately 50% of dental amalgam is elemental mercury, which releases low levels of mercury vapor.16
The Basis of the Controversy
Some individuals have an allergy or sensitivity to mercury or the other components of dental amalgam that causes oral lesions or other contact reactions. The main source of concern revolves around the mercury vapor, however, which is inhaled and absorbed by the lungs.16
As with most substances, the degree of harm caused by mercury in the body is related to the amount to which the patient is exposed. Very low levels generally have no ill effects. At higher levels—for instance, when workers are exposed to mercury through their jobs—it can cause symptoms such as nervousness, fatigue, irritability, memory loss, and headaches.17
Although the mercury in amalgam was once believed to be inert, there is evidence now that mercury vapor is released as these fillings wear.18 Several reviews of the research have concluded that the amount of mercury released from amalgam in the mouth is very low.17 A report from the Health Care Research Collaborative of the University of Illinois at Chicago School of Public Health, the Healthier Hospitals Initiative, and Health Care Without Harm titled “Mercury in Dental Amalgam and Resin-Based Alternatives: A Comparative Health Risk Evaluation” suggests beginning to phase out mercury-containing amalgam. Peter Orris, MD, MPH, a coauthor of the report and professor of occupational and environmental health sciences at the University of Illinois School of Public Health, said, “We found no evidence of a negative effect on patients’ health from either mercury amalgams or the alternatives used in restorations. Yet the alternatives were less hazardous to the general environment and the public’s health.”18
The Official Position
On July 28, 2009, the FDA issued a final regulation in which it reclassified the mercury component of dental amalgam from Class I (low risk) to Class II (moderate risk). Despite this, the agency wrote, “While elemental mercury has been associated with adverse health effects at high exposures, the levels released by dental amalgam fillings are not high enough to cause harm in patients.”19
The ADA responded to the FDA regulation by underscoring its position that dental amalgam is safe, as well as affordable and durable. “Dental amalgam has been studied and reviewed extensively, and has established a record of safety and effectiveness,” the association stated after the ADA Council on Scientific Affairs’ review of the literature on amalgam safety from January 2004 to April 2009. “Based on the results of this review,” the Council said, “the scientific evidence supports the position that amalgam is a valuable, viable, and safe choice for dental patients.”20
Final Thought
The abundance of health care information available to patients can be empowering—but it also open the door for misinformation and concern. Understanding the FDA and ADA official positions for triclosan, BPA, and mercury in dental amalgam can help dentists provide patients with the best evidence-based information available, allowing them to make informed choices about their treatment.
References
1. Triclosan: What Consumers Should Know. Food and Drug Administration website. www.fda.gov/forconsumers/consumerupdates/ucm205999.htm. Accessed December 27, 2012.
2. Buehlmann M, Frei R, Fenner L, Dangel M, Fluckiger U, Widmer AF. Highly effective regimen for decolonization of methicillin-resistant Staphylococcus aureus carriers . Infect Control Hosp Epidemiol. 2008;29(6):510-516.
3. Tackling Triclosan: Congress Recommends Review Based in Part on SRP Research. National Institute of Environmental Health Sciences website. https://niehs.nih.gov/research/supported/dert/cris/programs/srp/phi/archives/publicpolicy/triclosan/index.cfm. Accessed December 26, 2012.
4. Coia JE, Duckworth GJ, Edwards DI, et al. Guidelines for the control and prevention of methicillin-resistant Staphylococcus aureus (MRSA) in healthcare facilities . J Hosp Infect. 2006;63(suppl 1):S1-S44.
5. Aiello AE, Larson EL, Levy SB . Consumer antibacterial soaps: effective or just risky? Clin Infect Dis. 2007;45(suppl 2):S137-S147.
6. Antibacterial Soaps: Being Too Clean Can Make People Sick, Study Suggests. Science Daily website. www.sciencedaily.com/releases/2010/11/101129101920.htm. Accessed December 26, 2012.
7. Chemical widely used in antibacterial hand soaps may impair muscle function. UC Davis News and Information website. https://news.ucdavis.edu/search/news_detail.lasso?id=10301. Accessed December 26, 2012.
8. Moyad MA. The New BPA Controversy. www.huffingtonpost.com/maria-rodale/the-new-bpa-controversy_b_1697549.html. Accessed February 12, 2013.
9. Bisphenol A (BPA): Questions and Answers about Bisphenol A. The National Institute of Environmental Health Sciences website. www.niehs.nih.gov/health/topics/agents/sya-bpa. Accessed February 12, 2013.
10. BPA from thermal paper passes through skin. Phys.org website. https://phys.org/news/2010-11-bpa-thermal-paper-receipts-skin.html#jCp. Accessed February 12, 2013.
11. Maserejian NN, Trachtenberg FL, Hauser R, et al. Dental composite restorations and psychosocial function in children . Pediatrics. 2012;130(2):e328-e338.
12. Johnson M. BPA may be linked to obesity in children, study says. Journal Sentinel website.. www.jsonline.com/features/health/bpa-may-be-linked-to-obesity-in-children-study-says-k36tgbu-170178916.html. Accessed February 12, 2013.
13. Bisphenol A (BPA) Information for Parents. US Department of Health and Human Services website. www.hhs.gov/safety/bpa. Accessed February 12, 2013.
14. Indirect Food Additives: Polymers . Federal Register. 2012;77(137). www.gpo.gov/fdsys/pkg/FR-2012-07-17/html/2012-17366.htm. Accessed February 12, 2013.
15. Council on Scientific Affairs Statement. ADA News website. www.ada.org/1766.aspx. Accessed February 12, 2013.
16. Medical Devices: About Dental Amalgam Fillings. US Food and Drug Administration website. www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DentalProducts/DentalAmalgam/ucm171094.htm#1. Accessed February 12, 2013.
17. Dental Amalgam: A Health Risk? Colgate Oral and Dental Health Resource Center website. www.colgate.com/app/CP/US/EN/OC/Information/Articles/Oral-and-Dental-Health-Basics/Checkups-and-Dental-Procedures/Fillings/article/Dental-Amalgam-A-Health-Risk.cvsp. Accessed February 12, 2013.
18. Health Care Without Harm [press release]. HCWH News website. www.noharm.org/global/news_hcwh/2012/jun/hcwh2012-06-13.php. Accessed February 12, 2013.
19. FDA Issues Final Regulation on Dental Amalgam [press release]. US Food and Drug Administration website. www.fda.gov/NewsEvents/Newsroom/Pressannouncements/ucm173992.htm. Accessed February 12, 2013.
20. Statement on Dental Amalgam: ADA Council on Scientific. American Dental Association website.www.ada.org/1741.aspx. Accessed February 12, 2013.
