Bite Registration Materials in Canada vs the US: Which Route Applies?

Quick facts

• The standard groups them, the regulators do not. ISO 4823:2021 "specifies the requirements and their test methods for elastomeric impression and bite registration materials." Neither country keeps a bite registration entry of its own.
• United States: there is no separate entry. A bite registration material is classified through 21 CFR 872.3660, impression material, which is Class II (special controls).
• United States: the tray is regulated separately from the material. A preformed impression tray is Class I under 21 CFR 872.6880, and a resin impression tray material is Class I under 21 CFR 872.3670.
• Canada: a material placed in the mouth is reached through the body-contact rules. Rule 2(2) places an invasive device intended to contact the oral cavity up to the pharynx at Class I.
• Canada: the class rises where the material is a denture material or an orthodontic appliance or accessory. Rule 3(a) classifies all denture materials and orthodontic appliances and their accessories as Class II.
• Canadian regulation text used here is current to 2026-09-21 and last amended 2026-06-17, as stated on the official consolidation.

Bite registration is the step between a preparation and a restoration, and it is often bought as an afterthought in the same order as impression material. The two products sit next to each other on the shelf and share an international standard, which makes it easy to assume they share a class. They do not, and the same product can land in different classes in the two countries. This article sets out both routes and the age of the material that decides which one applies.

How does bite registration differ between Canada and the United States?

The difference is that the American route classifies the material by the impression section and the Canadian route classifies it by where it goes.

In the United States, 21 CFR 872.3660 describes impression material as a device composed of materials such as alginate or polysulfide, intended to be placed on a preformed impression tray and used to reproduce the structure of a patient's teeth and gums, and intended to provide models for study and for production of restorative prosthetic devices such as gold inlays and dentures. It places the device in Class II with special controls.

Read the wording closely, because it does two things at once. It gives examples of materials rather than a closed list, which is why a polyvinyl siloxane or a polyether falls inside it, and it describes the function as reproducing the structure of teeth and gums. A bite registration material records the relationship between the two arches rather than reproducing a surface, so it is not described by the identification paragraph word for word. The American code has no other section that describes it, and in practice a bite registration material is handled through the impression material section and the class that section carries.

The neighbouring entries show how finely the American code divides the same appointment. A preformed impression tray has its own Class I entry at 872.6880, and a resin impression tray material has its own Class I entry at 872.3670. The material that records the bite is the only part of the sequence with no entry of its own.

Canada sorts differently. Schedule 1 begins by asking how the device meets the body. A material that is placed in the mouth and contacts the oral cavity is an invasive device for the purposes of the regulations, and Rule 2(2) places an invasive device intended to contact the oral cavity up to the pharynx, the nasal cavity up to the nasopharynx, or the ear canal up to the tympanic membrane at Class I. That is the starting class for a bite registration material.

The class rises when the material stops being a recording medium and becomes part of a prosthesis. Rule 3(a) classifies all denture materials and orthodontic appliances, and their accessories, as Class II. A material used to fabricate a denture or an orthodontic appliance therefore leaves Rule 2(2) behind and takes Class II, while a material used to record an occlusal relationship does not.

Item	Canada	United States
Named entry for bite registration material	None in Schedule 1	None; reached through 872.3660
Starting class	Rule 2(2), Class I, oral cavity contact	872.3660, Class II, impression material
Class where the material is for a denture or appliance	Rule 3(a), Class II	872.3660, Class II
Impression tray	Rule 2(2), Class I	872.6880, Class I
Resin tray material	Rule 2(2), Class I	872.3670, Class I
Sorting key	Where the device contacts the body and what it becomes	Which section describes the function

Which route applies to which material?

The material family decides the standard, and the intended use decides the class.

ISO 4823:2021 is the standard for elastomeric impression and bite registration materials, and it states its own limitation: it does not address possible biological hazards associated with the materials, and says that assessment of those hazards is addressed in ISO 7405 and the ISO 10993 series. A practice that buys an elastomeric registration material should therefore expect two documents rather than one, a performance standard and a biological evaluation, and the note in the standard is the reason.

The hydrocolloid family is covered separately. ISO 21563:2021 specifies the requirements and test methods for hydrocolloid impression materials and states that it helps determine whether elastic aqueous agar and alginate hydrocolloid dental impression materials, as prepared for retail marketing, are of the quality needed for their intended purposes, and that it also specifies requirements for labelling and instructions for use.

The class still does not follow the material. An alginate used to record a bite and an alginate used to make a study model can be the same powder, and the American position remains the impression material section while the Canadian position remains Rule 2(2) unless the material is destined for a denture or an appliance. What changes across the border is the American Class II and the Canadian Class I for the ordinary registration material.

Material	Standard	United States	Canada
Elastomeric bite registration material	ISO 4823:2021	872.3660, Class II	Rule 2(2), Class I
Elastomeric impression material	ISO 4823:2021	872.3660, Class II	Rule 2(2), Class I
Alginate or agar hydrocolloid	ISO 21563:2021	872.3660, Class II	Rule 2(2), Class I
Material intended for a denture or appliance	ISO 4823:2021 or ISO 21563:2021	872.3660, Class II	Rule 3(a), Class II
Preformed impression tray	Not a material standard	872.6880, Class I	Rule 2(2), Class I
Resin impression tray material	Not an elastomer	872.3670, Class I	Rule 2(2), Class I

What does the standard group that the regulators do not?

ISO 4823:2021 is the clearest example of the gap, because it names both functions in one scope sentence. The standard treats an elastomeric material as a material, and it applies the same requirements and test methods whether the material is used to record a surface or a relationship.

The regulators do not follow the standard's grouping. The American code has four entries in the same part of the listing, three of which name a material or a tray and none of which names a registration material: impression material at Class II, resin impression tray material at Class I, preformed impression tray at Class I, and the hydrocolloid materials inside impression material. The Canadian code has no dental registration entry at all; it has body-contact rules, and those rules are indifferent to the material family.

For a practice the consequence is procedural rather than academic. When a supplier quotes a class, the class should be quoted against a route rather than against a material name, and the route should be written on the purchase record. The two questions a buyer should be able to answer are: which function does this material perform in the appointment, and for a Canadian purchase, is the material destined for a denture or an appliance. The first question decides the American position and the second decides whether the Canadian class is Class I or Class II.

What should a practice record for a registration material?

Four records, and the first is the one that closes the class question.

• The intended use. Whether the material is used to record an occlusal relationship, to reproduce a surface, or to fabricate a denture or appliance, because in Canada that statement decides between Rule 2(2) and Rule 3(a).
• The standard the material is supplied against. ISO 4823:2021 for an elastomeric material or ISO 21563:2021 for a hydrocolloid, quoted by number and year on the purchase record.
• The biological evaluation. The supplier's statement against ISO 10993-1:2018, since ISO 4823:2021 expressly leaves biological hazards to the ISO 7405 and ISO 10993 series.
• The lot, working time and setting time. The lot used for each patient and the handling figures the practice worked to, so that a failed registration can be traced to material or technique.

Which consumables does a registration step consume?

A registration or impression step is a small chairside set: the material, the tray, and the moisture control that keeps the field dry. For practices buying at case level, the wholesale ordering page sets out account and case terms and the B2B wholesale collection lists the lines held for institutional buyers. The alginate impression material covers the hydrocolloid side of the family, the cotton rolls cover moisture control at the field, and practices that also run a sterilizer can pair the sterilization monitoring collection with the biological indicator 5-pack trial.

Sources

1. 21 CFR 872.3660, impression material
2. 21 CFR 872.6880, preformed impression tray
3. 21 CFR 872.3670, resin impression tray material
4. 21 CFR 872.3690, tooth shade resin material
5. 21 CFR 872.9, limitations of exemptions
6. Medical Devices Regulations, SOR/98-282, full text and Schedule 1
7. ISO 4823:2021, elastomeric impression and bite registration materials
8. ISO 21563:2021, hydrocolloid impression materials
9. ISO 10993-1:2018, biological evaluation of medical devices
10. ISO 4049:2019, polymer-based restorative materials
11. ISO 22674:2016, metallic materials for dental restorations
12. ISO 6872:2015, dental ceramic materials
13. openFDA device classification API
14. FDA device classification database
15. Royal College of Dental Surgeons of Ontario, standards and guidelines
16. Canadian Dental Association
17. American Dental Association, infection control and sterilization
18. Public Health Ontario, infectious diseases guidance
19. World Health Organization, oral health fact sheet
20. Health Canada, medical devices

Related reading

• Dental Impression Materials in Canada vs the US: Which Class
• Dental Impression Trays in Canada vs the US
• Cotton Rolls in Canada vs the US: Which Saliva Absorber Rules

CliniEco Medical supplies dental, eye care and laboratory consumables of the kind described in this article. MDEL #35334. This article is written for dental, laboratory and procurement professionals and is not clinical or regulatory guidance; the choice of registration material, the technique used and the classification decision belong to the practitioner and to the requirements that apply to the practice.

Frequently Asked Questions

Is there a separate bite registration material entry in the United States?

No. The American code has no entry that names a bite registration material, and the product is classified through 21 CFR 872.3660, impression material, at Class II with special controls. The tray and the tray material have their own Class I entries instead.

How does Canada classify a bite registration material?

Through the body-contact rules. A material placed in the mouth and contacting the oral cavity is an invasive device for the purposes of the regulations, and Rule 2(2) places a device intended to contact the oral cavity up to the pharynx at Class I. Rule 3(a) lifts a denture material or orthodontic appliance and its accessories to Class II.

Can the same material be Class I in Canada and Class II in the United States?

Yes. An elastomeric registration material is reached through the impression material section at Class II in the United States, while in Canada the same material falls under Rule 2(2) at Class I unless it is destined for a denture or an appliance.

Which standard covers bite registration materials?

ISO 4823:2021, which specifies the requirements and test methods for elastomeric impression and bite registration materials. Hydrocolloid materials are covered by ISO 21563:2021 instead.

Does ISO 4823:2021 cover biological safety?

No. The standard states that it does not address possible biological hazards associated with the materials and that assessment of those hazards is addressed in ISO 7405 and the ISO 10993 series. A practice should expect a separate biological evaluation statement.

What should be recorded for a registration material?

The intended use in the appointment, the standard the material is supplied against quoted by number and year, the supplier's biological evaluation statement, and the lot with the working and setting times the practice worked to.