**Draft** **Guidance for Industry** **and FDA Staff**

**Class II Special Controls Guidance Document:**

**Dental Precious Metal Alloys**

***Draft Guidance***

**This guidance document is being distributed for comment purposes
only.**

**Document issued on: \[release date of FR Notice\]**

Comments and suggestions regarding this draft document should be
submitted within **90** days of publication in the *Federal Register* of
the notice announcing the availability of the draft guidance. Submit
written comments to Dockets Management Branch (HFA-305), Food and Drug
Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852.
Alternatively, electronic comments may be submitted to
[[http://www.fda.gov/dockets/ecomments]{.underline}](http://www.fda.gov/dockets/ecomments).
All comments should be identified with the docket number listed in the
notice of availability that publishes in the *Federal Register*.

For questions regarding this document, contact Mr. Michael E. Adjodha at
301-827-5283 or via email at mea@cdrh.fda.gov.

**W** **hen final, this guidance will supersede** **\"Guidance Document
for the Preparation of Premarket** **Notifications \[510(k)\'s\] for
Dental Alloys, March 3, 1997\"**

**U.S. Department Of Health and Human Services**

**Food and Drug Administration**

**Center for Devices and Radiological Health**

**Dental Devices Branch**

**Division of Anesthesiology, General Hospital,**

**Infection Control,** **and Dental Devices**

**Office of Device Evaluation**

**Preface**

#### 

**Additional Copies**

Additional copies are available from the Internet at:
[http://www.fda.gov/cdrh/\[+++specific](http://www.fda.gov/cdrh/%5Bspecific)
address\], or CDRH Facts-On-Demand. In order to receive this guidance
via your fax machine, call the CDRH Facts-On-Demand system at
800-899-0381 or 301-827-0111 from a touch-tone telephone. Press \"1\" to
enter the system. At the second voice prompt, press \"1\" to order a
document. Enter the document number (**1415***)* followed by the pound
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**Table of Contents**

**Section Page**

[1. Background 1](#__RefHeading___Toc38195392)

[2. Scope 2](#__RefHeading___Toc38195394)

[3. Risks To Health 3](#__RefHeading___Toc38195396)

[4. Mechanical Properties For Casting Alloys
4](#__RefHeading___Toc38195452)

[5. Mechanical Properties For PFM Alloys 4](#__RefHeading___Toc38195453)

[6. Biocompatibility 4](#__RefHeading___Toc38195458)

[7. Labeling 5](#__RefHeading___Toc38195461)

[8. Limitations Of Exemption From Premarket Notification
5](#__RefHeading___Toc38195462)

Draft Guidance for Industry and FDA Staff

Class II Special Controls Guidance Document: Dental Precious Metal
Alloys

***This draft guidance, when finalized, will represent the Food and Drug
Administration\'s (FDA\'s) current thinking on this topic. It does not
create or confer any rights for or on any person and does not operate to
bind FDA or the public. You can use an alternative approach if the
approach satisfies the requirements of the applicable statutes and
regulations. If you want to discuss an alternative approach, contact the
FDA staff responsible for implementing this guidance. If you cannot
identify the appropriate FDA staff, call the appropriate number listed
on the title page of this guidance.***

1.  []{#__RefHeading___Toc38195392 .anchor}Background

FDA is proposing to designate this guidance document as a special
control to exempt gold-based alloys and precious metal alloys for
clinical use (hereafter referred to as dental precious metal alloys)
from premarket notification. For brevity, FDA refers to gold-based
alloys and precious metal alloys for clinical use as dental precious
metal alloys. This guidance document is being issued in conjunction with
a Federal Register notice announcing the proposal to designate a special
control. This guidance is issued for comment purposes only. If a final
rule is not issued designating this guidance as a special control, the
guidance will not be issued.

This guidance document describes a means by which dental precious metal
alloy devices may comply with the requirement of Class II Special
Controls. Designation of this guidance document as a special control
means that manufacturers of dental precious metal alloy devices who
follow the recommendations listed in this document, before introducing
their device into commercial distribution in the United States, will be
able to market their device without being subject to the premarket
notification requirements of section 510(k) of the Act.

Section 510(m) of the Act provides that FDA may exempt a class II device
from the premarket notification requirements under section 510(k) of the
act if FDA determines that premarket notification is not necessary to
provide reasonable assurance of the safety and effectiveness of the
device. FDA has determined premarket notification is not necessary to
provide reasonable assurance of the safety and effectiveness of this
generic type of device if the manufacturer follows the recommendations
in this special controls guidance or equivalent measures to address the
risks identified in this guidance. Thus, persons who intend to market a
device of this type do not need to submit a premarket notification to
FDA and receive agency clearance prior to marketing the device, but as a
class II device, the device must comply with the general and special
controls (Section 513(a)(1)(B)).

Following the effective date of a final rule exempting the device,
manufacturers of dental precious metal alloy devices will need to
address the issues covered in this special control guidance. However,
the manufacturer need only show that its device meets the
recommendations of the guidance or in some other way provides equivalent
assurances of safety and effectiveness.[^1] If manufacturers cannot
comply with these recommendations or equivalent measures, they will not
be exempt from the requirements of premarket notification and will need
to submit a premarket notification and receive clearance for their
device prior to marketing.

FDA\'s guidance documents, including this guidance, do not establish
legally enforceable responsibilities. Instead, guidances describe the
Agency\'s current thinking on a topic and should be viewed only as
recommendations, unless specific regulatory or statutory requirements
are cited. The use of the word *should* in Agency guidances means that
something is suggested or recommended, but not required.

[]{#__RefHeading___Toc38195394 .anchor}Scope

FDA identifies a dental precious metal alloy as a device, classified
under 21 CFR §872.3060 below:

> Sec. 872.3060 Gold-based alloys and precious metal alloys for clinical
> use.
>
> \(a\) Identification. Gold-based alloys and precious metal alloys for
> clinical use are mixtures of metals, the major components of which are
> gold, silver, or palladium. They also may contain a small quantity of
> copper or platinum. The device is intended to fabricate dental
> appliances, such as crowns and bridges, for patients.
>
> \(b\) Classification. Class II

A dental precious metal alloy may be primarily composed of gold, silver,
platinum, or palladium, with lesser amounts of other elements such as
copper and zinc. The device is intended to fabricate:

-   all-metal (cast) dental appliances such as crowns and bridges; or

-   the coping or substrate to which is fused a ceramic coating for
    fabricating dental appliances such as crowns and bridges.

This classification includes cast and porcelain-fused-to-metal (PFM)
high noble and noble alloys and solders. The product codes associated
with this classification identification are:

-   EJT Alloy, Gold Based, for Clinical Use

-   EJS Alloy, Precious Metal, for Clinical Use

The scope of this guidance does not include base metal alloys, which is
addressed in the draft guidance entitled, **Class II Special Controls
Guidance Document: Dental Base Metal Alloys**,
[[http://www.fda.gov/cdrh/ode/guidance/1416.pdf]{.underline}](http://www.fda.gov/cdrh/%5Bspecific),
also issued for comment at this time. This guidance also does not
include any mercury (Hg) amalgam alloys or dental Hg, which are
classified in 21 CFR 872.3050 and 21 CFR 872.3700, respectively.

2.  Risks to Health

FDA has identified the following risks to health associated with the use
of the dental precious metal alloy in the tables below, depending on
whether the device is a casting metal alloy or a PFM alloy. FDA
recommends the following measures to mitigate the identified risks in
this guidance, as shown in the tables below.

**Casting Alloys**

  --------------------------- -------------------------------------------
  **Identified Risks**        **Recommended Mitigation Measures**

  Device failure              Section 4. Mechanical Properties for
                              Casting Alloys

  Adverse tissue reaction     Section 6. Biocompatibility

  Improper use                Section 7. Labeling
  --------------------------- -------------------------------------------

**PFM Alloys**

  --------------------------- -------------------------------------------
  **Identified Risks**        **Recommended Mitigation Measures**

  Device failure              Section 5. Mechanical Properties for PFM
                              Alloys

  Adverse tissue reaction     Section 6. Biocompatibility

  Improper use                Section 7. Labeling
  --------------------------- -------------------------------------------

The mechanical properties of the device may be insufficient to support
the required loads and lead to device failure. Porcelain may deform,
crack, and debond from the metal because of incompatibilities. These
device failures may result in ineffective treatment, revision, and
possibly minor, temporary impairment for the patient.

Some alloy compositions may not be biocompatible. Poor biocompatibility
may result in adverse tissue reaction.

Inadequate labeling may result in improper use. Improper use may result
in ineffective treatment and may cause minor, temporary impairment for
the patient.

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# Mechanical Properties for Casting Alloys

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# We recommend that precious metal casting alloys conform to the FDA- recognized standard below. 

-   

-   **American National Standard/American Dental Association
    Specification** **No. 5-1997, \"Dental Casting Alloys\"** (ANSI/ADA
    Specification No. 5)

In particular, Table 5-1 of the ANSI/ADA Specification No. 5 specifies
the minimum mechanical properties for casting alloys.

For precious metal solders (brazing alloys), we recommend conformance to
the FDA- recognized standard below.

-   

-   **American National Standard/American Dental Association
    Specification** **No. 88-2000, \"Dental Brazing Alloys\"** (ANSI/ADA
    Specification No. 88)

In particular, Section 4.5 of ANSI/ADA Specification No. 88 specifies
the minimum mechanical properties for solders.

# Mechanical Properties for PFM Alloys

We recommend that precious metal casting alloys conform to the FDA-
recognized standard below.

-   

-   **American National Standard/American Dental Association
    Specification** **No. 38-2000, \"Metal-Ceramic Dental Restorative
    Systems\"** (ANSI/ADA Specification No. 38)

In particular, Table 1 of the ANSI/ADA Specification No. 38 specifies
the minimum mechanical properties of the metal. Table 2 of this standard
specifies the minimum mechanical properties of the porcelain for these
metals. Section 4.3.3 of this standard specifies the minimum bond
compatibility index between the metal and porcelain.

3.  

4.  

5.  

6.  

7.  []{#__RefHeading___Toc38195458 .anchor}Biocompatibility

We recommend that you insure the biocompatibility of your device by
complying with the tests in the following standard for a permanent
contact, external communicating device on tissue, bone, or dentin in
accordance with the applicable requirements of ISO-10993 (instead of
ANSI/ADA Specification No. 41, which is incorporated by reference in
ANSI/ADA Specification No. 5). See Blue Book Memorandum #G95-1, entitled
\"Use of International Standard ISO-10993, Biological Evaluation of
Medical Devices Part 1: Evaluation and Testing,\"
<http://www.fda.gov/cdrh/g951.html>, for additional guidance on the use
of ISO-10993.

[]{#__RefHeading___Toc38195461 .anchor}Labeling

As a prescription device, under [21 CFR
801.109](http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?FR=801.109),
the device is exempt from having adequate directions for lay use.[^2]

# Limitations of Exemption from Premarket Notification

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FDA\'s decision to exempt a Class II device from the requirement of
premarket notification is based on the existing and reasonably
foreseeable characteristics of devices within that generic type that
currently are, or have been, in commercial distribution. Section 21 CFR
872.9 specifies the limitations to exemption. If any of these
limitations apply, your device is not exempt and you must submit a
premarket notification.

[^1]: We recommend that you document how you have addressed the
    recommendations in your design history file. Manufacturers must
    maintain design controls, including a design history file, in
    accordance with 21 CFR 820.30.

[^2]: Final labeling must comply with the requirements of 21 CFR 801
    before a medical device is introduced into interstate commerce.