Medical Devices; Classification of Temporomandibular Joint Implants

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Food and Drug Administration

21 CFR Part 872

[Docket No. 92N-0281]

Medical Devices; Classification of Temporomandibular Joint

Implants

AGENCY: Food and Drug Administration, HHS.

ACTION: Final rule.

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SUMMARY: The Food and Drug Administration (FDA) is classifying four

temporomandibular joint (TMJ) implants, the total temporomandibular

joint prosthesis, the glenoid fossa prosthesis, the mandibular condyle

prosthesis, and the interarticular disc prosthesis (interpositional

implant), into class III (premarket approval). These actions are being

taken under the Federal Food, Drug, and Cosmetic Act (the act), as

amended by the Medical Device Amendments of 1976 (the 1976 amendments)

and the Safe Medical Devices Act of 1990 (the SMDA).

EFFECTIVE DATE: January 19, 1995.

FOR FURTHER INFORMATION CONTACT: Joseph M. Sheehan, Center for Devices

and Radiological Health (HFZ-84), Food and Drug Administration, 2098

Gaither Rd., Rockville, MD 20850, 301-594-4765, ext. 157.

SUPPLEMENTARY INFORMATION:

I. Background

In the Federal Register of September 18, 1992 (57 FR 43165), FDA

issued a proposed rule to classify certain TMJ implants into class III.

Initially, FDA provided for interested persons to submit written

comments on the proposal by November 17, 1992. In response to a request

for an extension of the comment period, in the Federal Register of

December 1, 1992 (57 FR 56876), FDA extended the comment period until

December 8, 1992.

Subsequently, in the Federal Register of February 14, 1994 (59 FR

6935), FDA reproposed to classify two TMJ implants, the mandibular

condyle prosthesis and the glenoid fossa prosthesis, into class III

(premarket approval) to reflect the recommendation of the Dental

Products Panel (the panel) with respect to the classification of these

devices.

II. Response to Comments

The agency received 54 comments responding to the proposed rule and

one comment responding to the reproposed rule. These comments were

submitted by a law firm, oral and maxillofacial surgeons who placed TMJ

implants, manufacturers and distributors of TMJ implants, and TMJ

implant recipients.

1. In the preamble to the proposed rule, FDA advised interested

persons that the agency lacked evidence that the total TMJ prosthesis

was legally in commercial distribution before May 28, 1976. If the

device was first introduced into interstate commerce after May 28,

1976, it would be in class III in accordance with section 513 of the

act (21 U.S.C. 360c). FDA specifically requested comments on this

issue. In response, FDA received several comments stating that the

total TMJ prosthesis was legally in commercial distribution in the

United States before May 28, 1976, and one comment to the contrary.

FDA has determined, from information submitted in comments, that

two firms, TMJ Implants, Inc., Golden, CO, and the Temporomandibular

Joint Research Foundation, La Cresenta, CA, were commercially

distributing the total TMJ prosthesis in the United States on or before

May 28, 1976. Thus, the agency has concluded that the total TMJ

prosthesis is, in fact, a preamendments device and should be classified

along with the other TMJ implants.

2. Several comments stated that classification of TMJ implants into

class III (premarket approval) might result in the unavailability of

these devices for clinical use or in a movement to ban them. One

manufacturer of total TMJ implants stated that, if the total TMJ

implant is classified into class III, the expense of preparing a PMA

would force that manufacturer to discontinue marketing the device.

Under the statute, FDA classifies a device into class III, and

subsequently requires submission of PMA's for the device, when FDA has

determined that premarket approval is necessary to provide reasonable

assurance of the safety and effectiveness of the device. The

classification of a device, therefore, is based on considerations

related to the safety or effectiveness of the device.

FDA disagrees that classifying TMJ implants into class III will

necessarily result in the unavailability and/or the banning of these

devices because of the procedural safeguards contained in the statute.

The effect of classifying a device into class III is to provide each

manufacturer of the device with sufficient time to conduct necessary

testing of the device (a minimum of 30 months) and then to submit a PMA

to FDA by a date to be set in a future regulation under section 515(b)

of the act (21 U.S.C. 360e(b)(1)). That regulation is promulgated using

notice-and-comment rulemaking, in conjunction with which manufacturers

are permitted to petition for reclassification. Moreover, pursuant to

section 501(f) of the act (21 U.S.C. 351(f)(1)), a preamendments device

may continue to be sold throughout this time period and while a PMA is

pending.

FDA is not attempting to ban TMJ implants by classifying them into

class III. In fact, by eventually requiring submission of PMA's for

these devices, FDA will be giving manufacturers the opportunity to

establish that the devices are safe and effective. The classification

of a device into class III neither results in nor is it related to the

banning of a device under section 516 of the act (21 U.S.C. 360f).

3. Several comments stated that, for reconstruction of the

temporomandibular joint, non-ProplastTM TMJ implant devices are

superior to autogenous materials. One comment stated that partial fossa

protheses are safe and effective. Comments from patients and TMJ

prostheses manufacturers stated that they experienced favorable results

following implantation of the total TMJ prosthesis.

In classifying these devices, FDA is determining the level of

regulatory control needed to provide reasonable assurance of their

safety and effectiveness. Whether non-ProplastTM TMJ implants are

superior in safety and effectiveness to autogenous materials, or

whether partial fossa prostheses are perceived as safe and effective,

is not relevant to this determination.

In accordance with section 513(a)(3) of the act, the agency relies

on valid scientific evidence to determine the classification of a

device. According to Sec. 860.7(c)(2) (21 CFR 860.7(c)(2)), valid

scientific evidence includes evidence from well-controlled

investigations, partially controlled studies, studies and objective

trials without matched controls, well-documented case histories

conducted by qualified experts, and reports of significant human

experience with a marketed device. Valid scientific evidence does not

include isolated case reports, random experience, reports lacking

sufficient details to permit scientific evaluation, or unsubstantiated

opinions. Thus, the isolated case reports, random testimonials, and

unsubstantiated opinions received in response to the proposed rule

cannot be regarded as valid scientific evidence upon which the

classification of TMJ implants can be based.

4. One comment stated that the agency's failure to provide the

panel information relating to TMJ devices made of materials other than

ProplastTM limited the panel's consideration and should limit the

scope of its classification recommendation accordingly.

FDA disagrees with this comment. As stated in the legislative

history of the Medical Device Amendments of 1976:

In requiring a panel's classification recommendation to include

a summary of the reasons for the recommendation and a summary of the

data upon which the recommendation is based, the objective is to

assure that the record accurately reflects the basis for the panel's

recommendations. The use of the term ``data'' is not intended to

refer only to the results of scientific experiments but should also

consist of less formal evidence, other scientific information, or

judgments of experts when available. The requirement is not intended

to imply that a panel must have received evidence with respect to

safety and effectiveness of a device before it can make a

classification recommendation. Under this premise, the burden of

providing evidence substantiating the safety and effectiveness of a

device rests on the manufacturers, and the absence of sufficient

data may be referred to in a panel's recommendation as the reason

for classification of a device into class III.

(See H. Rept. No. 94-853, 94th Cong., 2d sess. 40 (1976), p. 40).

5. One comment asserted that the references cited by FDA in the

proposed rule classifying the total TMJ implant did not exist at the

time of the panel meeting and, therefore, could not have been evaluated

by the panel when making its recommendation.

FDA disagrees with this comment. It is true that some of the

information cited by FDA in support of its proposed classification of

the total TMJ implant did not exist at the time of the panel's April

21, 1989, meeting. However, the proposed rule reflected not only the

panel's recommendations, but also FDA's determinations regarding the

proper classification of these devices. The proposed rule did not state

or imply that the panel relied on all the data cited by the agency in

support of the proposed rule.

6. Several comments suggested that, when classifying these devices,

FDA should distinguish TMJ prostheses containing ProplastTM from

those not containing that material. These comments recommended that

only devices containing ProplastTM should be classified. Some

comments stated that the risks to health identified in the proposed

rule are based only on data associated with the failure of TMJ

prostheses containing ProplastTM. One comment stated that

ProplastTM implants and non-ProplastTM implants (specifically

cobalt chrome and polymethylmethacrylate (PMMA) prostheses) should be

classified separately because the difference in the material used in

these implants significantly affects their safety and effectiveness.

Several comments stated that surgeons and TMJ implant manufacturers had

observed no specific cases of the risks to health identified in the

proposed rule in several patients implanted with a non-ProplastTM

total TMJ prosthesis. Some comments stated that these risks to health

were not observed in patients implanted with TMJ prostheses

manufactured by specific manufacturers. In contrast, several comments

said that these risks were observed often in patients implanted with

TMJ implants containing ProplastTM.

According to Sec. 860.5(c)(3), when FDA initially classifies a

device, it may consider safety and effectiveness data developed for

other devices of the same generic type. A generic type of device

includes devices that do not differ significantly in purpose, design,

material, energy source, function, or any other feature related to

safety and effectiveness, and for which similar regulatory controls are

sufficient to provide reasonable assurance of safety and effectiveness

(see Sec. 860.3(i)).

The transcript of the April 21, 1989, panel meeting demonstrates

that the panel considered TMJ implants composed of various materials,

i.e., silicone, ProplastTM, dural grafts, fascia, vitallium,

acrylic, meniscle and silastic, before making its recommendations with

respect to classification. Evidence submitted during the panel meeting

revealed that similar risks and similar safety and effectiveness

concerns are associated with all TMJ implants, regardless of material

composition. Based on the evidence provided, the panel concluded that

TMJ devices composed of different materials raise the same safety and

effectiveness questions. Thus, the panel concluded, and FDA agrees,

that TMJ implants of all materials should be regulated within the four

generic types of devices identified because the devices do not differ

significantly in the safety and effectiveness questions raised and,

consequently, similar regulatory controls will be needed to provide

reasonable assurance of their safety and effectiveness.

7. Comments stated that one of the health risks identified in the

proposed rule, loosening of the total TMJ prosthesis, is directly

related to the health of the bone at the implant interface. These

comments asserted that loosening of the device does not occur unless

there is a void of suitable bone.

As stated in the preamble to the proposed rule, FDA has determined

that the screws used to anchor the implant may loosen, resulting in

implant loosening or displacement which may cause changes in bite,

difficulty in chewing, limited joint function and unpredictable wear on

implant components (see Refs. 2 through 5). The agency has not received

any new information to cause FDA to change its opinion.

8. Some comments asserted that FDA should classify all the TMJ

implants into class II because special controls would allow the agency

to impose special conditions on these devices, such as postmarket

surveillance. One of these comments, received from a TMJ implant

manufacturer, recommended that FDA classify TMJ cobalt-chrome-PMMA

implants into class II.

FDA disagrees with these comments. FDA believes that insufficient

information exists to establish that special controls would provide

reasonable assurance of the safety and effectiveness of these devices.

FDA believes that a PMA is necessary to provide such assurance.

Furthermore, postmarket surveillance is not limited to class II

devices. Thus, at some future time, FDA may request that manufacturers

of TMJ implants conduct postmarket surveillance of these devices.

9. One comment urged that the total temporomandibular joint

prosthesis and the interarticular implant be given high priority in

calling for PMA's. One comment disagreed, stating that FDA cannot give

the total TMJ prosthesis high priority in calling for PMA's when the

panel recommended low priority. Another comment expressed concern that

manufacturers of these prostheses will not have to submit PMA's to FDA

for at least 2\1/2\ years and will be permitted to market the devices

in the interim.

Pursuant to sections 501(f) and 515(b) of the act, TMJ implant

manufacturers may continue to commercially distribute their devices

without filing a PMA for 30 months after the effective date of the

final rule classifying these implants into class III or until 90 days

after FDA issues a final rule requiring premarket approval for the

devices, whichever is later. Moreover, section 515(i) of the act shows

a clear congressional intent that FDA move forward with requiring the

submission of PMA's for all preamendments devices. Thus, regardless of

the priority assigned for calling for PMA's, eventually PMA's will be

required for all class III preamendments devices that are not

reclassified. Furthermore, it should be noted that a panel

recommendation is only a recommendation that FDA may adopt or reject.

FDA believes that it is appropriate to require PMA's for all TMJ

implants as soon as possible under the act.

10. Two comments objected that the glenoid fossa prosthesis and the

mandibular condyle prosthesis should not be classified into class III

because the panel did not recommend that they be classified into class

III.

Subsequent to issuing the proposed rule, the panel reconvened on

February 11, 1993, and recommended that the mandibular condyle

prosthesis and the glenoid fossa prosthesis be classified into class

III. Based on this recommendation, FDA issued a reproposed rule in the

Federal Register of February 14, 1994 (59 FR 6935), to classify the

devices into class III.

11. One comment stated that the classification process for the TMJ

implants was flawed and should be reinitiated because of events which

transpired between the April 1989 panel recommendation and the issuance

of the proposed rule. During this time, the SMDA was passed. Among

other things, the SMDA changed the classification definitions for

medical devices.

FDA disagrees with this comment. It is the agency's position that

the SMDA does not require the agency to obtain a new classification

recommendation from a panel which had recommended classification under

the previous standard.

As stated previously, the agency is not bound to adopt a panel's

recommendation. Moreover, in light of the significant risks to health

identified by the panel, FDA believes it is extremely unlikely that the

panel would have recommended that the devices be classified into class

II under the new definition.

12. On its own initiative, FDA has deleted the words, ``naturally

occurring'' from the identifications of glenoid fossa prosthesis and

mandibular condyle prosthesis because the standard of care now

indicates that these devices may now interface not only with naturally

occurring surfaces but also with artificial surfaces.

III. References

The following referencees have been placed on display in the

Dockets Management Branch (address above) and may be seen by interested

persons between 9 a.m. and 4 p.m., Monday through Friday.

1. Transcripts of the Dental Products Panel meeting, April 21,

1989.

2. Transcripts of the Dental Products Panel meeting, February

11, 1993.

3. Fontenot, M. G., and J. N. Kent, ``In-vitro and In-Vivo Wear

Performance of TMJ Implants,'' abstract, International Association

of Dental Research, 1991.

4. Kent, J. N., and M. S. Block, ``Comparison of FEP and UPE

Glenoid Fossa Prosthesis,'' abstract, International Association of

Dental Research, 1991.

5. ``Clinical Information on the Vitek TMJ Interpositional (IPI)

Implant and the Vitek-Kent (VK) and Vitek-Kent 1 (VK-1) TMJ

Implants,'' and ``Vitek Patient Notification Program,'' an FDA

publication, 1991.

6. Kent, J. N., ``VK Partial and Total Joint Reconstruction,''

Current Concepts of TMJ Total Joint Replacement, University of

Medicine and Dentistry of New Jersey, pp. 1-8, March 1992.

7. Primely, D., Jr., ``Histological and Radiological Evaluation

of the ProplastTM-Teflon Interpositional Implant in

Temporomandibular Joint Reconstruction Following Meniscectomy,''

thesis, Master Degree in Oral Maxillofacial Surgery, University of

Iowa, May 1987.

8. Westlund, K. J., ``An Evaluation Using Computerized

Tomography of Clinically Asymptomatic Patients Following

Meniscectomy and Temporomandibular Joint Reconstruction Using the

ProplastTM-Teflon Interpositional Implant,'' thesis, Masters

Degree in Oral and Maxillofacial Surgery, University of Iowa,May

1989.

9. Wagner, J. D., and E. L. Mosby, ``Assessment of

ProplastTM-Teflon Disc Replacements,'' Journal of Oral and

Maxillofacial Surgery, 48:1140-1144, 1990.

10. Florine, B. K., et al., ``Tomographic Evaluation of

Temporomandibular Joints Following Discoplasty or Placement of

Polytetrafluoroethylene Implants,'' Journal of Oral and

Maxillofacial Surgery, 48:183-188, 1988.

11. Heffez, L., et al., ``CT Evaluation of TMJ Disc Replacement

with a ProplastTM Teflon Laminate,'' Journal of Oral and

Maxillofacial Surgery, 45:657-665, 1987.

12. Ryan, D. E., ``Alloplastic Implants in the Temporomandibular

Joint,'' Oral and Maxillofacial Surgery Clinics of North America,

1:427, 1989.

13. Valentine, J. D., ``Light and Electron Microscopic

Evaluation of ProplastTM II TMJ Disc Implants,'' Journal of

Oral and Maxillofacial Surgery, 47:689-696, 1989.

14. Logrotteria, L., et. al., ``Patient with Lymphadenopathy

Following Temporomandibular Joint Arthroplasty with

ProplastTM,'' The Hour of Craniomandibular Practice, vol. 4,

No. 2:172-178, 1986.

15. Berarduci, J. P., et al., ``Perforation into Middle Cranial

Fossa as a Sequel to Use of a ProplastTM-Teflon Implant for

Temporomandibular Joint Reconstruction,'' Journal of Oral and

Maxillofacial Surgery, 46:496-498, 1990.

16. Berman, D. N., and S. L. Pronstein, ``Osteo Phytic Reaction

to a Polytetrafluoroethylene Temporomandibular Joint Implant,'' Oral

Surgery, Oral Medicine, Oral Pathology (continues the Oral Surgery

Section of the American Journal of Orthodontics and Oral Surgery),

69:20-23, 1990.

IV. Environmental Imapct

The agency has determined under 21 CFR 25.24(e)(2) that this action

is of a type that does not individually or cumulatively have a

significant effect on the human environment. Therefore, neither an

environmental assessment nor an environmental impact statement is

required.

V. Analysis of Impacts

FDA has examined the impacts of the final rule under Executive

Order 12866 and the Regulatory Flexibility Act (Pub. L. 96-54).

Executive Order 12866 directs agencies to assess all costs and benefits

of available regulatory alternatives and, when regulation is necessary,

to select regulatory approaches that maximize net benefits (including

potential economic, environmental, public health and safety, and other

advantages; distributive impacts; and equity). The agency believes that

this final rule is consistent with the regulatory philosophy and

principles identified in the Executive Order. In addition, the final

rule is not a significant regulatory action as defined by the Executive

Order and so is not subject to review under the Executive Order.

The Regulatory Flexibility Act requires agencies to analyze

regulatory options that would minimize any significant impact of a rule

on small entities. Because this rule does not impose any new

requirements, the agency certifies that the final rule will not have a

significant economic impact on a substantial number of small entities.

Therefore, under the Regulatory Flexibility Act, no further analysis is

required.

List of Subjects in 21 CFR Part 872

Medical devices.

Therefore, under the Federal Food, Drug, and Cosmetic Act, and

under authority delegated to the Commissioner of Food and Drugs, 21 CFR

part 872 is amended as follows:

PART 872--DENTAL DEVICES

1. The authority citation for 21 CFR part 872 continues to read as

follows:

Authority: Secs. 501, 510, 513, 515, 520, 701 of the Federal

Food, Drug, and Cosmetic Act (21 U.S.C. 351, 360, 360c, 360e, 360j,

371).

2. New Secs. 872.3940, 872.3950, 872.3960, and 872.3970 are added

to subpart D to read as follows:

Sec. 872.3940 Total temporomandibular joint prosthesis.

(a) Identification. A total temporomandibular joint prosthesis is a

device that is intended to be implanted in the human jaw to replace the

mandibular condyle and augment the glenoid fossa to functionally

reconstruct the temporomandibular joint.

(b) Classification. Class III.

(c) Date PMA or notice of completion of a PDP is required. The

effective date of the requirement for premarket approval has not been

established. See Sec. 872.3.

Sec. 872.3950 Glenoid fossa prosthesis.

(a) Identification. A glenoid fossa prosthesis is a device that is

intended to be implanted in the temporomandibular joint to augment a

glenoid fossa or to provide an articulation surface for the head of a

mandibular condyle.

(b) Classification. Class III.

(c) Date PMA or notice of completion of a PDP is required. The

effective date of the requirement for premarket approval has not been

established. See Sec. 872.3.

Sec. 872.3960 Mandibular condyle prosthesis.

(a) Identification. A mandibular condyle prosthesis is a device

that is intended to be implanted in the human jaw to replace the

mandibular condyle and to articulate within a glenoid fossa.

(b) Classification. Class III.

(c) Date PMA or notice of completion of a PDP is required. The

effective date of the requirement for premarket approval has not been

established. See Sec. 872.3.

Sec. 872.3970 Interarticular disc prosthesis (interpositional

implant).

(a) Identification. An interarticular disc prosthesis

(interpositional implant) is a device that is intended to be an

interface between the natural articulating surface of the mandibular

condyle and glenoid fossa.

(b) Classification. Class III.

(c) Date PMA or notice of completion of a PDP is required. The

effective date of the requirement for premarket approval hasnot been

established. See Sec. 872.3.

Dated: November 25, 1994.

D. B. Burlington,

Director, Center for Devices and Radiological Health.

[FR Doc. 94-31161 Filed 12-19-94; 8:45 am]

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