History of Dental Amalgam: From Taveau's Invention to ADA Endorsement

Timeline

Year	Milestone
1816	Auguste Taveau (France) develops silver-mercury amalgam; too soft, expands on setting.
1826	Taveau improves formula using tin, silver, and mercury – first clinically viable amalgam.
1830s	Amalgam introduced to US by Crawcour brothers; controversy over mercury toxicity ("amalgam war").
1844	American Society of Dental Surgeons (ASDS) declares amalgam use malpractice; members pledge abstinence.
1856	ASDS dissolves; American Dental Association (ADA) formed (1859) without anti-amalgam stance.
1895	ADA endorses copper-amalgam (copper added to reduce marginal corrosion) for posterior restorations.
1908	G.V. Black standardizes alloy composition (Ag 67%, Sn 25%, Cu 6%, Zn 2%) – "extension for prevention" cavity design.
1960s	High-copper alloys (admixed & unicompositional) replace low-copper; ↓ creep, ↑ strength, ↓ corrosion.
1990s–present	Resin composites surpass amalgam for aesthetics; Minamata Convention (2013) phases down amalgam globally.

Composition Evolution

• Low-copper (traditional): γ₂ phase (Sn₇₋₈Hg) weak, corrodes → marginal breakdown.
• High-copper (admixed): Spherical Ag-Cu eutectic + lathe-cut Ag-Sn → η' (Cu₆Sn₅) replaces γ₂.
• High-copper (unicompositional): Single spherical alloy (Ag-Sn-Cu) → uniform η'.

Mercury Safety & Regulation

• Elemental mercury vapor released during placement/removal; peak exposure < occupational limits.
• No credible evidence linking amalgam to systemic disease in general population (FDA, ADA, WHO, SCENIHR reviews).
• Contraindicated: mercury allergy, severe renal impairment, pregnancy (precautionary), children <6 (some jurisdictions).
• Minamata Convention: Phase-down via prevention, minimally invasive dentistry, alternative materials.

Current Status

• Amalgam remains durable, cost-effective, technique-forgiving for posterior load-bearing restorations.
• Composite resins now preferred for aesthetics and adhesive dentistry; bulk-fill composites narrow performance gap.
• ADA: Amalgam is safe and effective; dentist-patient discussion should guide material choice.