Dental Devices; Endodontic Dry Heat Sterilizer

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Food and Drug Administration

21 CFR Part 872

[Docket No. 95N-0033]

Dental Devices; Endodontic Dry Heat Sterilizer

AGENCY: Food and Drug Administration, HHS.

ACTION: Final rule.

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SUMMARY: The Food and Drug Administration (FDA) is issuing a final rule

to require the filing of a premarket approval application (PMA) or a

notice of completion of a product development protocol (PDP) for the

endodontic dry heat sterilizer, a medical device. Commercial

distribution of this device must cease, unless a manufacturer or

importer has filed with FDA a PMA or a notice of completion of a PDP

for its version of the endodontic dry heat sterilizer within 90 days of

the effective date of this regulation. This regulation reflects FDA's

exercise of its discretion to require a PMA or notice of completion of

a PDP for the preamendments device.

EFFECTIVE DATE: January 21, 1997.

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

and Radiological Health (HFZ-215), Food and Drug Administration, 1350

Piccard Dr., Rockville, MD 20850, 301-827-2974.

SUPPLEMENTARY INFORMATION:

I. Background

In the Federal Register of August 12, 1987 (52 FR 30082), FDA

issued a final rule classifying the endodontic dry heat sterilizer

(Sec. 872.6730 (21 CFR 872.6730)) into class III (premarket approval).

Section 872.6730 applies to: (1) Any endodontic dry heat sterilizer

that was in commercial distribution before May 28, 1976, the date of

enactment of the Medical Devices Amendments of 1976 (Pub L. 94-295),

and (2) any device that FDA has found to be substantially equivalent to

the endodontic heat sterilizer and that has been marketed on or after

May 28, 1976.

In the Federal Register of December 30, 1980 (45 FR 86155), FDA

published the recommendation of the Dental Device Classification Panel

(the panel), of the Medical Devices Advisory Committee, an FDA advisory

committee, regarding the classification of the device.

The panel recommended that the device be in class III (premarket

approval) because the device presented an unreasonable risk of illness

or injury. According to the panel, the devices failed to sterilize

adequately various endodontic and dental instruments. The panel felt

that the failures could be the result of: (1) The device not reaching

and maintaining an adequate temperature because of a faulty thermostat

or (2) the result of unequal heat distribution by the glass beads

throughout the well despite sufficient heat. The panel believed that it

was not possible to establish an adequate performance standard for the

device because satisfactory performance had never been demonstrated.

The panel recommended the device to be subject to premarket approval to

ensure that manufacturers of the device demonstrate satisfactory

performance and that further study was necessary to determine the

causes of the device's ineffectiveness.

FDA agreed with the panel's recommendation that endodontic dry heat

sterilizers be classified into class III. FDA believed that there was

an unreasonable risk of illness or injury because of the potential

failure of the device to sterilize dental instruments adequately. FDA

believed that there was inadequate information to determine if general

controls or a performance standard would provide reasonable assurance

of safety and effectiveness.

In the Federal Register of June 7, 1995 (60 FR 30032), FDA

published a proposed rule to require the filing under section 515(b) of

the Federal Food, Drug, and Cosmetic Act (the act) (21 U.S.C. 360e(b))

of a PMA or a notice of completion of a PDP for the endodontic dry heat

sterilizer. In accordance with section 515(b)(2)(A) of the act, FDA

included in the preamble to the proposal the agency's proposed findings

with respect to the degree of risk of illness or injury designed to be

eliminated or reduced by requiring the device to meet the premarket

approval requirements of the act, and the benefits to the public from

use of the device (60 FR 30032 at 30037). The June 7, 1995, proposed

rule also provided an opportunity for interested persons to submit

comments on the proposed rule and the agency's findings. Under section

515(b)(2)(B) of the act, FDA also provided an opportunity for

interested persons to request a change in the classification of the

device based on new information relevant to its classification. Any

petition requesting a change in classification of the endodontic heat

sterilizer was required to be submitted by September 5, 1995. The

comment period closed August 7, 1995.

[[Page 2901]]

FDA received one comment in response to the proposed rule. The

comment recommended that the endodontic dry heat sterilizer remain

classified as class III, until sufficient evidence has been submitted

documenting the safety and efficacy of these devices. It also pointed

out concern in the use of the endodontic dry heat sterilizer for the

generalized sterilization of instruments because of marked temperature

gradients within the well which could result in inadequate

sterilization and the appropriate use of the devices to sterilize large

bulk instruments. FDA agrees with the concern and the comment that a

PMA be required for endodontic dry heat sterilizers.

II. Findings With Respect to Risks and Benefits

A. Degree of Risk

The primary risk to health is infection through the use of

inadequately sterilized instruments. A review of the literature has

identified the following problems associated with the use of endodontic

dry heat sterilizers which can contribute to the inability of these

devices to sterilize instruments, including general medical

instruments.

1. Temperature Variations Within the Well.

There are many reports in the literature describing the temperature

variations found within the wells of endodontic dry heat (glass bead)

sterilizers. It has been reported that the temperature distribution in

four brands of these devices at two different sites from the center and

at six different depths in the well varied significantly depending upon

location. The temperature was highest at a location which was closest

to the wall and midway down from the surface. Furthermore data have

demonstrated temperature variations as much as 10 deg.C over time near

the periphery of the well. The information in the literature suggested

that endodontic dry heat (glass bead) sterilizers should not be used as

a substitute for dry heat convection or steam sterilization sterilizers

because of the temperature variations.

2. Exposure Times for the Sterilization of Instruments.

The manufacturers' recommended exposure times for sterilization of

instruments vary from as short as 2 seconds to 45 seconds for

sterilizers whose purported operating temperatures were from 218 to 260

deg.C. However, location in the well, size and mass, number and shape

of the instruments must be factored into the amount of time required

for sterilization. Larger instruments composed of more metal take more

time to heat than smaller instruments. It was reported that the time

required to raise an instrument's temperature was dependent upon its

size. Small instruments such as root canal files heated rapidly while

large instruments such as cotton pliers never reached the specified

operating temperature. Endodontic dry heat (glass bead) sterilizers

have been reported to be effective only with small instruments that can

be imbedded into the heat transfer media and that their effectiveness

has not been demonstrated for instruments of larger bulk. The insertion

of large instruments would reduce the temperature of the glass beads

below the minimum temperature required for sterilization. Heat

conduction in a large, partially imbedded device would be variable.

Precleaning of the instruments before insertion into the heat

transfer medium in the well of the sterilizer is critical to the

effectiveness of the device. It was reported that if endodontic

instruments were contaminated with a protein load (blood), the time

required for sterilization was more than doubled. Such adverse

conditions can easily be found in infected or gangrenous pulp. There

are reports that spores, which are more resistant to sterilization

processes than vegetative organisms, have been found in the oral cavity

and cultured from pulp material.

3. Lack of Methods to Monitor the Performance/Sterilization Efficacy of

the Device.

There are no identified methods for the routine monitoring of the

sterilization efficacy of the endodontic dry heat sterilizer such as

the ones which exist with the traditional sterilization methods, i.e.,

steam autoclaves, hot air dry heat sterilizers, or ethylene oxide

sterilizers. Chemical and biological indicators are available for

routine monitoring of the efficacy of the cycle parameters and for the

validation of the process specifications for these traditional

sterilizers. The data in the literature, as noted above, suggest that

the user can not be assured that instruments inserted into an

endodontic dry heat sterilizer will be reliably exposed to the minimum

cycle parameters required for sterilization, i.e., exposure of the

device to the set temperature for the specified time.

4. Warm-up Times for Endodontic Dry Heat (Glass Bead) Sterilizers.

Reported warm-up times for these devices range from 15 minutes to

50 minutes with the average of 15-20 minutes. However, it has been

reported that it took up to 30 minutes for the temperature of the glass

beads to stabilize even though the manufacturer claimed that the device

reached operating temperature within 10 minutes.

5. Maintenance of Sterility After Removal From the Device.

The instructions for use for most of the devices do not instruct

the user on the proper procedure to remove instruments from the device

and how to maintain sterility of the instruments or the processed

portion of the instrument during the cool down period. Because of the

temperature variations reported within the wells, there exists the

possibility that heat resistant microorganisms could survive on the

glass beads in the cooler regions near the top of the glass beads and

contaminate the instruments as they are removed from the well. Since

endodontic dry heat sterilizers only process that portion of the

instrument which has been inserted into the glass beads, there is also

the potential of contaminating a sterile field with a device which had

not been properly processed.

6. Heat Transfer Medium Remaining Upon the Devices.

Occasionally the heat transfer medium has been observed to adhere

to wet instruments. If the particles are not detected before the

devices are inserted into the site, then they could cause blockage of

the wound site. This would cause significant problems if the heat

transfer media were glass beads or molten metal.

B. Benefit of the Device

The endodontic dry heat sterilizer is used to decontaminate

endodontic instruments during a procedure on a single patient provided

the instruments are properly cleaned to remove organic debris before

insertion into the unit. In theory the number of microorganisms that

would be introduced into the same site or into a new site on the same

patient during a single procedure would be reduced. Once the procedure

is over, the instruments should be processed using traditional methods

of decontamination and sterilization before use in the next patient.

[[Page 2902]]

C. Discussion of Risks and Benefits

The data in the literature indicate a lack of uniform sterilization

parameters among the various endodontic dry heat (glass bead)

sterilizers which have been marketed. Because of the temperature

variations found within the wells of glass bead sterilizers, exposure

of an instrument to an adequate sterilizing temperature is difficult to

determine and must be confirmed independently for each instrument. Also

determination of the sterilization exposure time is dependent upon

instrument size and mass. It has been reported that some instruments

never reach the appropriate temperature because of their size and mass;

and that endodontic dry heat sterilizers are not appropriate for large

bulk instruments.

Review of the claims being made for these devices suggests that

manufacturers are expanding the claims beyond those originally defined

in Sec. 872.6730. The claims have been expanded to include the

sterilization of general medical instruments and electrolysis and

acupuncture needles, and to devices not regulated by FDA such as

manicurist's instruments. The claims imply that these devices can be

used as a substitute for the traditional methods of sterilization. It

has been noted in the literature that endodontic dry heat sterilizers

are not sterilizers, but are decontaminating devices and that they

should not be used to sterilize instruments between patients. No system

exists for: (1) Monitoring the exposure of the instrument to

sterilization conditions or (2) demonstrating that the sterilization

exposure parameters have been achieved within the well. Only the

portion of the instrument which is inserted into the heat transfer

medium has the potential of being sterilized; the portion which is not

inserted into the glass beads is not sterilized. The use of endodontic

dry heat sterilizers with general medical instruments and with the

implication as a substitute sterilization method raises serious safety

and efficacy questions which the manufacturers of these devices have

not adequately addressed. There is the serious risk of infection

through the use of inadequately processed instruments.

III. Final Rule

Under section 515(b)(3) of the act, FDA is adopting the findings as

published in the preamble to the proposed rule and is issuing this

final rule to require premarket approval of the generic type of device,

endodontic dry heat device, by revising Sec. 872.6730(c).

Under the final rule, a PMA or a notice of completion of a PDP is

required to be filed with FDA within 90 days of the effective date of

this regulation for any endodontic dry heat sterilizer device that was

in commercial distribution before May 28, 1976, or any device that FDA

has found to be substantially equivalent to such a device on or before

September 5, 1995. An approved PMA or declared completed PDP is

required to be in effect for any such device on or before 180 days

after FDA files the application. Any other endodontic dry heat

sterilizer device that was not in commercial distribution before May

28, 1976, or that FDA has not found, on or before September 5, 1995, to

be substantially equivalent to an endodontic dry heat sterilizer device

that was in commercial distribution before May 28, 1976, is required to

have an approved PMA or declared completed PDP in effect before it may

be marketed.

If a PMA or notice of completion of a PDP for an endodontic dry

heat sterilizer device is not filed on or before September 5, 1995,

that device will be deemed adulterated under section 501(f)(1)(A) of

the act (21 U.S.C. 351(f)(1)(A)), and commercial distribution of the

device will be required to cease immediately. The device may, however,

be distributed for investigational use, if the requirements of the

investigational device exemption (IDE) regulations part 812 (21 CFR

part 812) are met.

Under Sec. 812.2(d) of the IDE regulations, FDA hereby stipulates

that the exemptions from the IDE requirements in Sec. 812.2(c)(1) and

(c)(2) will no longer apply to clinical investigations of the

endodontic dry heat sterilizer devices. Further, FDA concludes that

investigational endodontic dry heat sterilizer devices are significant

risk devices as defined in Sec. 812.3(m) and advises that as of the

effective date of the regulations in Sec. 872.6730(c), requirements of

the IDE regulations regarding significant risk devices will apply to

any clinical investigation of an endodontic dry heat sterilizer device.

For any endodontic dry heat sterilizer device that is not subject to a

timely filed PMA or notice of completion of a PDP, an IDE must be in

effect under Sec. 812.20 on or before September 5, 1995, or

distribution of the device for investigational purposes must cease. FDA

advises all persons currently sponsoring a clinical investigation

involving an endodontic dry heat sterilizer to submit an IDE

application to FDA no later than August 7, 1995, to avoid the

interruption of ongoing investigations.

IV. Environmental Impact

The agency has determined under 21 CFR 25.24(a)(8) and (e)(4) 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. 96-354).

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 for more than 10 years the manufacturers of

these devices have been aware of the need to prepare PMA's for these

devices, 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 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. Section 872.6730 is amended by revising paragraph (c) to read as

follows:

Sec. 872.6730 Endodontic dry heat sterilizer.

* * * * *

[[Page 2903]]

(c) Date premarket approval application (PMA) or notice of

completion of product development protocol (PDP) is required. A PMA or

notice of completion of a PDP is required to be filed with the Food and

Drug Administration on or before September 5, 1995, for any endodontic

dry heat sterilizer that was in commercial distribution before May 28,

1976, or that has on or before September 5, 1995, been found to be

substantially equivalent to the endodontic dry heat sterilizer that was

in commercial distribution before May 28, 1976. Any other endodontic

dry heat sterilizer shall have an approved PMA or declared completed

PDP in effect before being placed in commercial distribution.

Dated:September 18, 1996.

Joseph A. Levitt,

Deputy Director for Regulations Policy, Center for Devices and

Radiological Health.

[FR Doc. 97-1336 Filed 1-17-97; 8:45 am]

BILLING CODE 4160-01-F