Comments to the FDA on “Dental Devices; Reclassification of Temporary Mandibular Condyle Prosthesis”

Division of Dockets Management
Food and Drug Administration
5630 Fishers Lane, Room 1061 (HFA-305)
Rockville, Maryland 20852

May 8, 2013

Comments of the National Research Center for Women & Families and the TMJ Association
“Dental Devices; Reclassification of Temporary Mandibular Condyle Prosthesis”
[Docket No. FDA-2012-N-1239]

The National Research Center for Women & Families and the TMJ Association oppose the reclassification of Temporary Mandibular Condyle prosthesis, a preamendments class III device, into class II.  The proposed special controls are not rigorous enough to provide a reasonable assurance of the device’s safety and effectiveness.

The permanent mandibular condyle prosthesis is a class III device that requires the more stringent Premarket Approval application (PMA).  If the FDA allows the temporary device to be cleared through the 510(k) process for a supposedly temporary indication to treat patients who had oral cancers removed, that creates a loophole for manufacturers to avoid the more thorough PMA process.

Temporary mandibular condyle prostheses should remain class III devices because they glide across the fossa of the skull, which, if penetrated, opens to the brain.  Renaming this device a “temporary mandibular condyle reconstruction plate” (TMCRP), for short-term use not to exceed 2 years, is disingenuous and misleading.  Since surgeons are very unlikely to recommend a surgical procedure of this magnitude for a patient without an urgent need, it is unlikely that these devices will be removed within 2 years except in cases where the temporary devices fail in that time.  In fact, a search of PubMed and other major sources has not found any research indicating the length of time the devices are implanted. There are case reports indicating that the devices are often implanted for more than two years.  In some cases, the patients were seriously harmed by long-term implantation.[end Schoning, H. and R. Emshoff. (1998) Primary temporary AO plate reconstruction of the mandible. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 86(6):667-72.] One study of 110 patients indicated that devices could fail even within the first 6 months.[end Shibahara, T. et al. (2002) Fracture of mandibular reconstruction plates used after tumor resection. J Oral Maxillofac Surg 60:182-185.] With so little scientific data, it is impossible to know how often these serious adverse events are occurring.  When the devices are being used beyond the two years, patients are inappropriately exposed to the health risks identified by FDA.

Nearly a dozen serious health risks are listed for the TMCRP, including the “user error” when a TMCRP is “used as a permanent prosthesis rather than a temporary reconstruction plate.”[end Federal Register (February 7, 2013).  Dental Devices; Reclassification of Temporary Mandibular Condyle Prosthesis (Proposed Order). Docket No. FDA-2012-N-1239.] No clinical data are available to determine the risks if these devices remain implanted for more than two years.  Other documented health risks of the device include facial nerve paralysis, chronic pain, infection, malocclusion, mechanical failure and migration of the screws or plates.  Research is needed to identify if migration of the device wears away the skull or causes further damage to mandibular bones.3

A down classification from Class III to Class II, and the resulting 510(k) clearance process, would allow a manufacturer to use less rigorous reviews to clear its device such as bench and biocompatibility tests. The special controls FDA has proposed in its draft guidelines do not include clinical trials, which would provide high-quality data demonstrating safety and effectiveness.

Even if these devices are actually used temporarily, the same products could then be used off-label for indications that FDA has designated are high risk and should require a PMA.  Down-classification for any indication creates a loophole which would allow manufacturers to avoid the more rigorous PMA review process.

Although the Dental Products Panel “only recommended that class II was appropriate for plates indicated in tumor resection cases,” the FDA has proposed using the device in “patients who have undergone any resective surgical procedures requiring removal of the mandibular condyle and mandibular bone.”3 Tumor patients are less likely to live for more than 2 years, so by expanding the usage to any patient undergoing resective procedures, this would dramatically increase the number of patients being treated with a device that lacks the more rigorous PMA review for safety and effectiveness, and the number of patients whose device would be implanted for more than 2 years.

One of the reasons FDA stated for reclassifying the device from class III into class II is “the relative absence of adverse events reports despite the longstanding use of these devices,” but it is well known that adverse events are under-reported on the MAUDE data base.  Under-reporting is especially likely for patients who are seriously ill, such as those with mandibular tumors.  Family members who are facing the likely death of a loved one will also be unlikely to use the MAUDE system to report adverse events and relate the device failure to the disease progression.  The lack of MAUDE reports is negated by the publication of case reports indicating serious adverse events, especially since case reports are rarely published.

While we support the Dental Products Panel’s 1997 recommendation that special controls include a registry to track the temporary mandibular condyle prosthesis devices, we are concerned that the panel did not state who would run the registry (the government or a private entity), and we note that the registry was not included in the FDA’s draft guideline special controls for TMCRP devices.  The special controls also do not specify who will have access to the registry.

We strongly disagree with FDA’s assertion that their proposed special controls “are appropriate to provide reasonable assurance of safety and effectiveness” for TMCRP devices.  These devices should remain in class III and require PMA review with clinical trials to ensure that the devices truly are safe and effective.

National Research Center for Women & Families
The TMJ Association

For more information, contact Paul Brown at (202) 223-4000 or