[Federal Register Volume 62, Number 13 (Tuesday, January 21, 1997)]
[Rules and Regulations]
[Pages 2900-2903]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1336]


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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