Gold has been used in dentistry for thousands of years, primarily for medical restorations like crowns, inlays, and bridges, though today it is also used cosmetically in grills. Its historical popularity stems from its unique properties, including high malleability and exceptional resistance to corrosion, which makes it remarkably durable in the oral environment. Understanding the safety of gold teeth requires separating the material’s chemical composition and its long-term mechanical effects on the mouth.
Biocompatibility and Systemic Health Concerns
Dental gold is rarely pure because 24-karat gold is too soft to withstand the intense forces of biting and chewing. It is typically a high-karat alloy, often ranging from 10K to 22K, with 16K (about 67% pure gold) being a common standard for dental crowns. Pure gold is highly biocompatible and chemically inert. However, other metals are intentionally blended in to increase hardness and longevity, such as platinum, palladium, silver, and copper.
The primary systemic concern comes from these non-gold components, particularly in lower-quality or non-noble alloys that contain less than 25% precious metal content. Some individuals can develop localized allergic reactions, such as contact dermatitis or stomatitis, to metals like nickel, copper, or palladium used as hardeners. While nickel is largely phased out of high-quality dental alloys, sensitivities are still possible and may manifest as chronic inflammation or redness of the adjacent gums.
A different chemical issue is galvanic corrosion, which occurs when two dissimilar metals are present in the wet, electrolyte-rich environment of the mouth. If a gold alloy restoration is placed next to a restoration made of a different metal, a small electrical current can be generated. This process can cause the leaching of metal ions from the less noble material into the surrounding tissues. However, high-noble gold alloys (those with over 60% precious metals) are highly resistant to corrosion.
Long-Term Effects on Dental Structure
The longevity of any restoration depends heavily on its marginal integrity, which is how tightly the edge of the crown seals against the natural tooth structure. Gold’s malleability allows dentists to “burnish” the margins, effectively closing microscopic gaps between the restoration and the tooth. This superior fit helps prevent bacteria and saliva from leaking underneath the crown, a common cause of secondary decay.
A significant mechanical consideration is the effect of the gold surface on the opposing natural teeth. Gold is a relatively soft metal that wears at a rate very similar to natural tooth enamel, which minimizes abrasion on the opposing bite surface. This property is a major advantage because materials harder than enamel can cause excessive wear on the teeth they grind against.
Gold surfaces are exceptionally smooth and dense, properties that naturally resist the adhesion of bacterial plaque. This reduced surface roughness simplifies oral hygiene and maintenance, which contributes to the long-term health of the surrounding gum tissues. Because gold can be cast thinly while maintaining strength, dentists often need to remove less natural tooth structure during preparation compared to other materials.
Comparing Gold to Alternative Materials
While gold offers unmatched durability, with some restorations lasting over 50 years, its use has declined dramatically due to the demand for superior aesthetics offered by modern materials. Porcelain and ceramic restorations can be color-matched precisely to the patient’s natural teeth, providing an invisible restoration that gold cannot achieve. Material choice balances the need for strength against the desire for a natural appearance.
Modern ceramics, such as zirconia, have improved significantly in strength and now offer high wear resistance without the aesthetic compromise of metal. These newer materials are designed to wear similarly to enamel, mitigating the risk of excessive abrasion on opposing teeth. These advances have positioned ceramics as the first-choice material for most anterior and visible posterior teeth.
Dentists still recommend gold in specific situations where its unique properties are advantageous over alternatives, such as in patients with severe teeth grinding or clenching (bruxism). This includes restorations in the very back of the mouth where chewing forces are highest or when there is limited space between the upper and lower teeth. In these high-stress environments, gold’s ability to be cast thinly and resist fracture maintains its reputation as a reliable and long-lasting option.