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General product and reprocessing information only, drawn from US regulator and CDC pages; it is not medical advice and does not replace a manufacturer’s instructions for use or a facility’s infection-control policy.
A dental tray is, most often, a set-up tray: a tray or cassette that holds the instruments for one procedure in order of use. The same words also name impression trays and whitening or fluoride trays, which are different devices. This guide helps a practice manager, dental assistant or supply buyer sort out which one is meant, what any tray must go through between patients, and where US rules say something specific about trays.
What “dental tray” can mean
Set-up (instrument) tray or cassette
A set-up tray organises the instruments for a procedure so they are laid out, reprocessed and stored together. What goes on it depends on the procedure and on the practice’s own protocol, so there is no single standard list; see the instrument guides for dental scalers and dental explorer types for individual items. How a tray differs from a rigid container or wrap is covered in sterilization containers.
Impression tray
An impression tray holds impression material against the teeth to take a mold. The material itself is a separate item, covered in dental impression material.
Whitening or fluoride tray
These are trays that hold a gel against the teeth. They are outside the scope of the checklist below, which concerns instrument and impression trays that are reprocessed between patients.
Dental impression tray: what it is and how it is classed
A dental impression tray is the carrier that holds impression material against the teeth and gums so the material can capture a mold. The US rules name two kinds: a preformed impression tray and a custom impression tray. The FDA describes the resin used for it in 21 CFR 872.3670: resin impression tray material is used in a two-step mold fabricating process to form a custom impression tray where a preformed tray is not suitable, for example for crowns, bridges or full dentures. That material is Class I (general controls) and exempt from premarket notification, subject to 21 CFR 872.9.
The impression material placed in the tray is a separate device. Under 21 CFR 872.3660 impression material, composed of materials such as alginate or polysulfide, is placed on a preformed tray to capture the teeth and gums, and it is Class II (special controls). See dental impression material and polyvinyl siloxane impression for the materials.
For reprocessing, the CDC lists reusable dental impression trays as semicritical items. Because most semicritical items in dentistry are heat-tolerant, the CDC says they should be sterilized using heat. If a semicritical item is heat-sensitive, the CDC says dental healthcare personnel should replace it with a heat-tolerant or disposable alternative, and if none is available, process it with at least high-level disinfection. The checklist further down applies to impression trays.
Fluoride tray: what it is and how it is classed
A fluoride tray is a tray that holds a fluoride product against the teeth. It is a delivery device, not the fluoride itself. The FDA defines one specific type in 21 CFR 872.6870: a disposable fluoride tray is a device made of styrofoam intended to apply fluoride topically to the teeth, and the patient bites down on the tray after it has been filled with a fluoride solution. It is Class I (general controls) and exempt from premarket notification, subject to 21 CFR 872.9 (FDA product code KMT, “Tray, fluoride, disposable”; FDA product classification page updated 10/26/2026). That regulation describes only the disposable styrofoam type, so it should not be read as covering every tray used with fluoride.
The fluoride product is regulated separately from the tray. The American Dental Association describes topical fluoride as gels, foams, rinses, varnish and silver diamine fluoride; says gels, foams and rinses are applied by a dental professional during dental visits; and says some home-use gels are available by prescription and must be prescribed by a dentist or physician. The ADA page does not describe a tray method, so how a particular tray is used belongs to its manufacturer’s instructions and the prescriber. For a fluoride varnish, which is painted on rather than held in a tray, see cavity varnish.
A fluoride tray is not the same device as a whitening tray, and neither is an instrument set-up tray; the reprocessing checklist below is written for instrument and impression trays reprocessed between patients, not for single-use disposable trays.
Purpose and setting
In a dental setting the tray is a handling unit: the instruments on it are cleaned, dried, packaged, sterilized, labelled and stored as a group. The checklist below therefore covers what must be true of any tray, rather than what instruments it carries.
Reprocessing checklist
Items below come from the CDC’s dental infection-control pages (Sterilization and Disinfection, and Best Practices for Sterilization in Dental Settings, both dated May 15, 2024). Follow the manufacturer’s instructions for the specific tray, wrap or container.
| Step or item | What the CDC says | Why it matters |
|---|---|---|
| Classification of reusable impression trays | Reusable dental impression trays are listed as semicritical items, which generally need heat sterilization. | Sets the reprocessing level for the tray. |
| Dryness before packaging | “Wet instruments can compromise the packaging material’s integrity and ability to maintain sterility.” | A wet load can undermine the package. |
| Inspect, then package | Dried instruments should be inspected, wrapped, packaged, or placed into container systems before heat sterilization. | Catches damage and keeps items protected after the cycle. |
| Packaging per manufacturer | Follow the manufacturer’s instructions for packaging patient-care items, including containers, wraps and indicators. | Packaging material is validated for particular uses. |
| Label | Packages should show the sterilizer used, the cycle or load number, and the date of sterilization, plus an expiration date if applicable. | Lets staff retrieve items if a processing failure is found. |
| Monitor the sterilizer | A spore test should be used at least weekly to monitor sterilizers. | Checks that the sterilizer is working. |
What varies
Three things change the checklist in practice. First, the kind of tray: a reusable impression tray is classed by the CDC as a semicritical item, and a set-up tray is handled according to its manufacturer and the practice protocol. Second, the packaging: wrap, pouch or rigid container, each used according to its manufacturer’s instructions. Third, the practice’s shelf-life policy, described next.
Storage, expiry and restocking
The CDC says sterile instruments and supplies should ideally be stored in covered or closed cabinets, and not under sinks or anywhere they might get wet. It describes two approaches to shelf life. A date-related approach assigns an expiration date and rotates stock first in, first out. An event-related approach treats a package as sterile until an event, such as tearing, wetting or puncture, compromises it. Either way, “If a package has been compromised, the contents should be reprocessed.”
Standards and rules that apply
- 21 CFR 872.3670, Resin impression tray material (Cornell LII copy of the eCFR, checked 2026-10-31): a device used in a two-step dental mold fabricating process, to form a custom impression tray where a preformed tray is not suitable. It is Class I (general controls) and exempt from premarket notification, subject to 21 CFR 872.9. If it is not labeled or otherwise represented as sterile, it is also exempt from the quality management system regulation in 21 CFR part 820 except records and complaint files (21 CFR 820.35).
- 21 CFR 872.3660, Impression material (Class II, special controls) and 21 CFR 872.6870, Disposable fluoride tray (Class I, general controls; styrofoam type only), both on Cornell LII, checked 2026-10-31.
- Common mis-citation: 21 CFR 872.6640 is “Dental operative unit and accessories”, the powered base for a handpiece and light. It is not a tray regulation.
- CDC dental infection-control pages listed under Sources, for reprocessing, labelling and storage.
FAQ
What is a dental impression tray?
A carrier that holds impression material against the teeth and gums to capture a mold. It may be a preformed tray or a custom tray formed from resin impression tray material (21 CFR 872.3670, Class I). The CDC lists reusable impression trays as semicritical items that generally need heat sterilization.
What is a fluoride tray?
A tray that holds a fluoride product against the teeth. The FDA defines the disposable styrofoam type in 21 CFR 872.6870 as a Class I device that the patient bites down on after it is filled with a fluoride solution. The fluoride product is regulated separately, and the ADA notes some home-use gels require a prescription.
What is a dental tray?
Usually a set-up tray: a tray or cassette that organises the instruments for one procedure in order of use. The term can also mean an impression tray or a whitening or fluoride tray.
Do reusable impression trays need sterilizing?
The CDC lists reusable dental impression trays as semicritical items, which generally need heat sterilization (CDC, May 15, 2024).
What should a sterilized tray package be labelled with?
The sterilizer used, the cycle or load number and the sterilization date, plus an expiration date if applicable (CDC, May 15, 2024).
How long does a sterilized tray stay sterile?
The CDC describes both date-related and event-related practice, and does not set one fixed period. A compromised package should be reprocessed.
Is a dental impression tray regulated by the FDA?
Resin impression tray material is a Class I device under 21 CFR 872.3670, exempt from premarket notification subject to 21 CFR 872.9.
Sources
- CDC, Sterilization and Disinfection (Dental Infection Prevention and Control), May 15, 2024: https://www.cdc.gov/dental-infection-control/hcp/summary/sterilization-disinfection.html (checked 2026-10-31).
- CDC, Best Practices for Sterilization in Dental Settings, last reviewed May 15, 2024: https://www.cdc.gov/dental-infection-control/hcp/dental-ipc-faqs/dental-sterilization.html (checked 2026-10-31).
- 21 CFR 872.3670, Resin impression tray material: https://www.law.cornell.edu/cfr/text/21/872.3670 (checked 2026-10-31).
- 21 CFR 872.3660, Impression material: https://www.law.cornell.edu/cfr/text/21/872.3660 (checked 2026-10-31).
- 21 CFR 872.6870, Disposable fluoride tray: https://www.law.cornell.edu/cfr/text/21/872.6870 (checked 2026-10-31).
- FDA, Product Classification, Tray, fluoride, disposable (KMT): https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpcd/classification.cfm?id=KMT (checked 2026-10-31).
- American Dental Association, Fluoride: Topical and Systemic Supplements: https://www.ada.org/resources/ada-library/oral-health-topics/fluoride-topical-and-systemic-supplements (checked 2026-10-31).
- Related guide: what is an autoclave.
