Direct comparison
Amalgam vs Composite: Materials & FDA Class
Amalgam vs composite as dental materials: composition, FDA device class, regulation numbers and FDA’s mercury statement, from 21 CFR and FDA pages.
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How do Dental amalgam, Composite (tooth shade resin material) compare side by side?
The table below compares Dental amalgam, Composite (tooth shade resin material) across 10 procurement-relevant dimensions, from what the regulation defines through source.
Side-by-side comparison
| Dimension | Dental amalgam | Composite (tooth shade resin material) |
|---|---|---|
| What the regulation defines | Elemental mercury plus an amalgam alloy, “for the direct filling of carious lesions or structural defects in teeth” (21 CFR 872.3070). | A device “composed of materials such as bisphenol-A glycidyl methacrylate (Bis-GMA) intended to restore carious lesions or structural defects in teeth” (21 CFR 872.3690). |
| Composition | About 50% elemental mercury by weight; the rest is a powdered alloy of silver, tin and copper (FDA). | Resin materials such as Bis-GMA (21 CFR 872.3690). Mercury is not part of the regulatory definition. |
| How it is supplied | Two components assembled at use: mercury (liquid in bulk, sachet or predosed capsule) and alloy (powder in bulk, tablet or predosed capsule). Each can also be a component device. | Defined as a single material in the regulation. |
| FDA device class | Class II (special controls); the special control is FDA’s guidance document on dental amalgam, mercury and amalgam alloy. | Class II. |
| Regulation number | 21 CFR 872.3070 | 21 CFR 872.3690 |
| openFDA product code | OIV (Dental Amalgam); EJJ (Alloy, Amalgam). The capsule, Capsule, Dental, Amalgam, is Class I, code DZS, 21 CFR 872.3110. | EBF (Material, Tooth Shade, Resin). |
| Mercury | FDA: amalgam “releases low levels of mercury in the form of a vapor.” FDA says available evidence does not show that this exposure causes adverse effects in the general population. | Not part of the material’s regulatory definition. |
| Groups FDA singles out | FDA lists pregnant women and fetuses, women planning pregnancy, nursing women and newborns, children (especially under six), people with neurological disease or impaired kidney function, and people with a known sensitivity or allergy to mercury or amalgam’s other metals. Anyone allergic or sensitive to its metals “should not get amalgam fillings.” | FDA names composite resins as a non-amalgam option and “strongly encourages” non-amalgam restorations for high-risk patients if the dentist considers them appropriate. |
| When each is the subject of FDA advice | FDA does not tell the general population to avoid amalgam; it advises against it for people allergic to its metals and encourages alternatives for the higher-risk groups above. | FDA cites it as an alternative for those groups, subject to the dentist’s judgement. The choice for an individual belongs with the treating dentist. |
| Source | FDA, “Dental Amalgam Fillings” (read 2026-10-30); 21 CFR 872.3070 (Cornell LII, read 2026-10-30); openFDA classification API (2026-10-30). | FDA, “Dental Amalgam Fillings” (read 2026-10-30); 21 CFR 872.3690 (Cornell LII, read 2026-10-30); openFDA classification API (2026-10-30). |
Common questions
Common questions about Dental amalgam vs Composite (tooth shade resin material)
How does glass ionomer compare with composite?
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Glass ionomer is a third option FDA names alongside composite resins as non-amalgam. Glass ionomer cements sit under the dental cement regulation, 21 CFR 872.3275 (Class II for cements other than zinc oxide-eugenol), a category defined by uses such as temporary fillings and base cements. The regulation text does not name glass ionomer.
Are amalgam and composite regulated the same way by FDA?
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Both are Class II devices, but under different regulations: dental amalgam under 21 CFR 872.3070 with special controls, and tooth shade resin material under 21 CFR 872.3690.
What does FDA say about mercury in amalgam?
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FDA says amalgam is about 50% elemental mercury by weight and releases low levels of mercury vapor, and that available evidence does not show adverse effects in the general population. It says developing nervous systems of fetuses and young children may be more sensitive to mercury vapor.
Going deeper
