Written and maintained by CASRAI Editorial Board
Last updated
General product information for clinic and supply staff. It is not medical or dental advice and does not describe clinical technique.
What is a periodontal file?
A periodontal file is a dental hand instrument whose head carries several cutting edges. The dental hygiene literature describes the head as built to fracture hardened deposit (calculus) and overhanging amalgam restorations by engaging them with those edges. The FDA lists the device by the name “File, Periodontic” as a Class 1 dental device under product code EMR and 21 CFR 872.4565.
Parts and design
Hodges describes a file as having three parts: a head, a shank and a handle. The head carries multiple cutting edges, and its shape may be round, oval, oblong or rectangular. The lip of the head, the cutting edge facing the shank and handle, sits at 90° or 105° to the shank, and shanks are either straight or contra-angled (Hodges, Dimensions of Dental Hygiene, November 2004).
FDA class of a periodontal file
In the FDA Product Classification Database, product code EMR carries the device name “File, Periodontic,” medical specialty Dental, device class 1 and regulation number 872.4565. That regulation, 21 CFR 872.4565, is titled “Dental hand instrument.” It places these hand instruments in Class I (general controls) and states that a device made of the same materials used before May 28, 1976 is exempt from premarket notification (510(k)), subject to the limitations in 21 CFR 872.9. The same regulation covers many other dental hand instruments, so a file shares its regulatory identity with instruments such as the dental curette.
Types of periodontal file
Hodges groups files by design. Every row below comes from that article.
| Type | Described characteristics |
|---|---|
| Working file | Cutting edges spaced farther apart; heads usually large and bulky. Hirschfeld files are the stated exception, with small heads and three cutting edges each. |
| Finishing file | Example given: Bedbug UW B, medium head, about 10 cutting edges. |
| Diamond-coated file | Double-ended, round or curette-like in design, with a 180° or 360° diamond coating. |
Hirschfeld and Orban numbering
The article lists the Hirschfeld #3/11, #5/11 and #9/10 files and the Orban #10/11 and #12/13 files as named working-file patterns. Numbering can differ between manufacturers’ catalogues, so check the pattern against a supplier’s own specification.
What to compare in a product listing
The specification points below are the ones the cited sources describe. They help when reading product descriptions.
- Regulatory identity: FDA product code EMR, Class 1, 21 CFR 872.4565.
- Head shape and edge count: round, oval, oblong or rectangular, and the number of cutting edges (three on Hirschfeld files, about ten on a finishing file such as Bedbug UW B).
- Lip angle and shank: 90° or 105° lip angle, and a straight or contra-angled shank.
- Maintenance: steel files have edges that are sharpened like those of a curette, while the article describes diamond-coated files as not needing sharpening.
For neighbouring instruments, see the CASRAI guides on the periodontal probe, the dental explorer and the dental curette.
Class 1 does not mean interchangeable
Class I describes the regulatory control level for the product code. It says nothing about head shape, edge count or design, which the sections above show do differ between files.
FAQ
What is a periodontal file?
A dental hand instrument with a head carrying multiple cutting edges, attached through a shank to a handle. See the parts section above.
What FDA class is a periodontal file?
Class 1, product code EMR, under 21 CFR 872.4565, which also states a 510(k) exemption subject to the limitations in 21 CFR 872.9.
What types of periodontal file are there?
Hodges describes working files, finishing files and diamond-coated files, with Hirschfeld and Orban patterns among the working files.
How is a file different from a curette?
A file has multiple cutting edges on its head, while a curette is a separate instrument type. Both fall under the same regulation, 21 CFR 872.4565. See the dental curette guide.
Sources
All sources below were checked on 2026-10-31.
- Hodges KO. “Using Files in Periodontal Therapy.” Dimensions of Dental Hygiene. 2004;2(11):16, 18-20. https://dimensionsofdentalhygiene.com/article/using-files-periodontal-therapy/. A 2004 professional-journal article.
- U.S. FDA, Product Classification Database (openFDA), product code EMR “File, Periodontic.” https://api.fda.gov/device/classification.json?search=product_code:EMR.
- 21 CFR 872.4565, Dental hand instrument. https://www.law.cornell.edu/cfr/text/21/872.4565.
