Questions remain about the quality of 'foreign' dental prostheses
by Regina L. Pfister, RDH, MSEd, and John R. Winings, CDT, MA
We know all too well of stories concerning products from China, shipped into the United States, and later found to be tainted with lead. What makes stories like this so frightening is that lead poses a serious health concern and is considered especially hazardous for young developing bodies. Exposures in young children often happen because of typical childhood behavior. Studies show that young children inevitably place items in their mouths, which makes them easy victims of lead poisoning. In adults, lead poisoning usually happens from occupational exposures by either breathing or swallowing the lead particles. Documented cases of lead poisoning are often not found until irreversible damage appears.1-3
What happens when an older person discovers that a dental appliance for the mouth contains lead? The story first uncovered in 2008 by a Columbus, Ohio, television station4 related how a senior citizen having problems with the "fit" of her new bridge returned to the dentist. The dentist attempted to correct the problem by grinding portions of the occlusal porcelain on the bridge. The report revealed that the porcelain on the ill-fitting device contained lead and was an outsourced product from China. Many times when we choose products we may overlook safety and quality, which is often less visible than a price tag. This article will discuss some of the factors surrounding outsourcing and its use in dentistry.
The term outsourcing is also known as gray marketing or offshoring. Regardless of the term, outsourced products are not new in manufactured goods. In fact, there is probably an outsourced duplicate of every type of product ever manufactured. What is new is that consumers and possibly dentists may be using outsourced products and not even know it.
There are different ways that outsourced dental prostheses come into the hands of U.S. dentists. The prosthesis can originate as a work order from a dental office and be sent to a broker laboratory in the U.S. where it is processed. The work order can then be relayed to an outsourced site for manufacturing. The completed prosthesis will be shipped back into the U.S. after being made at the outsourced site.5,6
Another route used in outsourced products is the direct shipping of the work order to the overseas lab. Usually there is a broker laboratory or "virtual lab" in the U.S. to handle administrative duties for the outsourced facility. A small number of staff may be used in the U.S. to perform minor adjustments and/or quality control checks. Any repackaging or relabeling of the prosthesis will happen at this location.5,6
Expensive shipping costs usually keep labs from outsourcing only a few cases. Dental labs using outsourced manufacturing sites have the majority of their work shipped out, leaving only the minor adjustments to be taken care of in the U.S.
By 2005, there was already a significant amount of outsourced lab work used by dental labs in this country5 even though consumers and even some dental offices receiving the products did not know they were outsourced. In addition, the National Association for Dental Laboratories (NADL) estimated in June 2009 that the outsourced work, "… though listed conservatively at 20%, it is expected to plateau at 35% to 40%." NADL also stated that the FDA had approached them in 2004 and 2007 because of the increasing number of imported dental devices passing through the U.S. borders.
There are various motives for outsourcing, but one major reason is the low cost. This may be enough motivation to lead dentists to outsource when first opening their practices, or for use on only certain populations. Prices range from one third to one half the price when compared to the U.S. dental prostheses.6
Another reason outsourcing continues to grow, as noted in Dr. Christensen's article, is the reduced hours for required lab procedures taught to dental students.5,6 This could suggest that the reduction does not allow dental students enough knowledge of various lab procedures or the importance of the education involved. This may convey to the new generation of dentists that well trained certified dental technicians are of little value. They may not understand how critical the need is for meticulous prostheses and how it will affect their practices.
It is also interesting that a recent NADL survey revealed that currently eight out of 50 dental schools use outsourcing for their clinics' prostheses.5,6 Graduates trained with little lab experience learn to accept the use of less educated and trained personnel for their lab services.
The dentist makes the diagnosis for the treatment plan and determines the type of prosthesis needed by the patient. The dental technician often must determine which suitable dental materials to use during the manufacturing of the specific device. The level of knowledge and skills of the person manufacturing the device will make the difference between a successful or unsuccessful case. The patient often does not understand the complexity of the prosthesis or that another person is involved in the completed product. However, the prostheses that result from the knowledge and skills of the person manufacturing them become a reflection of the dentist and his or her practice. All choices made by dental professionals ultimately affect the patient.
Problems with outsourcing
Assuming quality is there and the cost is low, the dentist must decide how important it is to communicate directly with the people manufacturing the dental device. The only direct relay of information will be through the broker lab. Often language barriers do not provide the exact interpretation of pertinent information that is especially important in complicated cases. The pick up by the shipping source may be the only contact a dentist has with the manufacturer of the prostheses.5
Once the completed outsourced dental prostheses arrive in the U.S., the final inspection will be left to the dentist, who must ensure that the prostheses are physically sound and good quality. However, as demonstrated by the Ohio case, the poor fit of the prosthesis was not recognized, and the content of the materials cannot be determined by observation alone. Therefore, a questionable restoration was (permanently) seated until the patient demanded that it be removed.4
Dental prostheses, such as porcelain crowns with metal bases, are regarded as "medical devices" by the Federal Drug Administration (FDA). The Center for Devices and Radiological Health division (CDRH) of the FDA regulates and supervises the development and administration of all medical devices.7
In providing safety to the public, medical devices are categorized by the level of risk they could present. The CDRH maintains that any risk by a Class I medical device could be controlled within the "manufacturing process." Some medical devices may also have "special controls" to ensure the safety and effectiveness of the devices.
At present, porcelain teeth are classified as Class II medical devices, whereas dental amalgam, mercury, and amalgam alloy devices are Class II medical devices with "special controls." The "special controls" label adds a recommendation to disclose the complete chemical composition used in the manufacturing of these products.8 A 2004 survey by the National Association of Dental Laboratories (NADL) found little information available concerning the content of materials for alloys, ceramics, or polymers used in outsourced prostheses.6
The FDA also oversees manufactured, repackaged, relabeled, and/or imported medical devices sold in the United States. Medical devices that are found to have any problems are required to be reported to the FDA. "Studies have shown that there is an overall lack of reporting any problem surrounding medical device adverse reactions."8
The U.S. dental laboratory industry is monitored by the CDRH.6 Laboratories currently fall under the quality system/good manufacturing practice regulations. A quality system, as defined by the FDA, satisfies requirements for fitness for use, safety, and performance.8 The controls over the manufacturing process are judged by the manufacturing laboratory or are "self regulated." The expectation of laboratories to use "expected responsible behavior" is an FDA oversight to ensure public safety. This regulation does little more than provide a list of facilities.
The FDA requires dental labs that outsource their work to overseas labs to give that information to the dentists receiving the prostheses. According to a 2009 dental lab survey, the information is given only upon request. In addition, even if dentists do obtain the information, the disclosure does not have to be passed along to patients.
This is why dentists may not know the prostheses have been outsourced. Therefore, almost half (44%) of dental labs support the disclosure of information, which would be filed in patients' permanent records. The dentist and patients should have knowledge of the manufactured location of any prosthesis. Though the FDA requires the disclosure of outsourced products to the dentist, the information is not required to be given to the patient. (Source: NADL and NBC Survey, June 2009)
The NADL, which is concerned for the public's safety regarding the lack of supervision over dental laboratories, continues to endorse the need for better regulations over dental labs and the qualifications of those manufacturing the prostheses. Some of the more specific regulations include, 1) the requirement of all laboratories to register with a state agency, 2) the requirement of labs to have at least one Certified Dental Technician (CDT) in each laboratory, and 3) the disclosure of materials used in each prosthesis.6
NADL also wants disclosure of the point of origin for each manufactured case, not the U.S. location where devices are repackaged or labeled.6 This recommendation would allow tracking of the origin of the manufactured prostheses if there are problems. Toys, foods, and various other items are required to have labels that designate where they were manufactured. It is reasonable for a patient who is having a dental device permanently placed in his or her body to have the option to choose the manufacturing location.
The NADL has also recommended a new standard for all materials used in dental prostheses. This recommendation would require that any material used must be acceptable for human tissue contact. Any dental lab manufacturing dental appliances for the U.S. would be required to verify that the materials used in dental devices are FDA approved.6
The lack of quality control over dental laboratories has forced the NADL to step up education that focuses on labs that outsource. Dentists that use outsourced products must understand that there is no reliable way to determine the materials used in the devices.6 The FDA does not "approve" any laboratories, though the same regulations required by U.S. dental labs are also meant for the outsourced labs. The FDA concedes that there is no reliable system in place to enforce these regulations. The ADA has suggested that all dentists identify where their prostheses are being manufactured and evaluate the practice of outsourcing as a way to protect their patients.9
Obviously, the regulations meant to provide oversight for dental laboratories and the products used in the manufacturing of dental devices are not well defined or even enforceable. The public may conclude that the recommendations and standards given by the NADL are more reasonable. Applying the definitions used by the FDA, one wonders why the NADL recommendations are not already in place as "expected responsible behavior" or "good manufacturing practices," if the goal is to ensure public safety.
The bridge found in the Ohio case contained 210 ppm of lead, which was noted at the time to be an "acceptable level" of lead.1 Some studies disagree on what the acceptable levels should be and note that constant "acceptable levels" of lead pose a threat. It has been speculated that the American Dental Association, which addresses acceptable levels of lead in dental materials such as porcelain, would aim for 50 ppm as a baseline.
Noticing the increase in products coming into the U.S. that contain lead inspired the CDC to put together a group of nine federal agencies to develop a comprehensive plan to keep out sources of lead in food and consumer products. Healthy People 2010 (http://www.healthypeople.gov/) listed the elimination of elevated blood lead levels in children as one of their main goals.1
The quantity is often available in outsourcing, but overall the quality is disappointing. Outsource products will continue to come into the country; therefore, clear enforceable, and uniform regulations are required to provide consumer safety. The collaboration of the ADA and NADL to enforce disclosure of material composition and point of origin of dental prostheses will demonstrate to the public the effort both entities provide for the safety of patients. The authors would add that a minimum educational requirement such as a two-year degree should be required with a test, along with NADL's suggestions. This would be more consistent with other health related careers.
The use of "best practices" instead of "expected behavior" would convey the quality of dental prostheses that dentistry should expect. The reporting of any problem in the dental profession, regardless of the dental member involved, reflects on everyone in the dental profession. It will be up to everyone to take ownership of their part in dentistry to make sure that only safe and quality dental devices are used in the United States.
Regina L. Pfister, RDH, MSEd, is an assistant professor in the School of Allied Health at Southern Illinois University Carbondale and has been a practicing dental hygienist for more than 20 years. She is a member of the American Dental Hygienists' Association, the Illinois Dental Hygienists' Association, and Kappa Delta Pi, an International Honor Society in Education.
John R. Winings CDT, MA, is an associate professor in dental hygiene in the School of Allied Health at Southern Illinois University Carbondale. He was formerly the program director for the Dental Technology Program. He has made presentations and published nationally, and served as a consultant in dental technology education for the Commission on Dental Accreditation. He is a member of the Editorial Advisory Board for the Journal of Dental Technology.
1. Department of Health and Human Services, Centers for Disease Control and Prevention. Preventing lead poisoning in children. 2005. Atlanta: CDC. Retrieved from http://www.cdc.gov/nceh/lead/publications/PrevLeadPoisoning.pdf.
2. Lidsky TI, Schneider JS. Lead neurotoxicity in children: basic mechanisms and clinical correlates. Brain. 2003 Jan;126(Pt 1):5-19.
3. Lanphear BP, Dietrich K, Auinger P, Cox C. Public Health Rep. 2000 Nov-Dec;115(6):521-9.
4. Seavert L. (producer). (2008, March 4). Lawmakers, FDA eye dental work report. [Podcast] Available from http://ww.10tv.com/live/content/teninvestigates/stories/2008/03/04.
5. Christensen GY. (2005). Dental laboratory technology in crisis: The challenges facing the industry. JADA , 136, 653-655.
6. Napier B. (2009 June). Report for American College of Prosthodontists from NADL. "2009 Future of dental technology conference" hosted by ADA.
7. FDA. Code of federal regulations Title 21 ceramic tooth. Retrieved from http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?fr=872.3920.
8. FDA. Medical Devices. Retrieved from MedicalDevices/Safety/ReportaProblem: http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm#3.
9. Findley JS. (2009, March 16). [Letter to Besser RE]. Retrieved from http://www.ada.org/sections/newsAndEvents/pde.
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