Metal teeth and galvanic or electrolytic currents in our mouths

An electrolytic current, often referred to as "galvanic" current, can occur in the mouth between dental restorations made of different metals, such as amalgam fillings and gold alloy crowns. This phenomenon is based on the principles of galvanic or electrogalvanic action, which occur when metals with different electric potentials come into contact in a conductive environment. Here's how it can happen in the context of dental restorations:

1. Dissimilar Metals:

- Dental amalgam is typically composed of a mixture of metals including silver, tin, copper, and mercury. Gold alloys used in dentistry may contain gold along with other metals like copper, palladium, and silver.

- Each metal has a different electrical potential, and when two dissimilar metals are present in the mouth, they can function like the electrodes of a battery.

2. Saliva as an Electrolyte:

- Saliva in the mouth contains electrolytes (such as sodium, potassium, and chloride ions) and thus can conduct electricity. This creates an environment conducive to galvanic action.

3. Formation of Galvanic Cell:

- When amalgam and gold alloy restorations are in close proximity or in contact, and saliva serves as the conductive medium, a galvanic cell can be formed. The metal with the higher electrical potential becomes the anode, and the one with the lower potential becomes the cathode.

- This can lead to a flow of electric current from one restoration to the other.

4. Effects of Galvanic Current:

- Some individuals may feel the effects of this current as a sharp pain or a metallic taste. This is more likely to occur soon after the placement of a new restoration and may diminish over time.

- The galvanic current can also accelerate corrosion of the metal restorations, potentially leading to increased wear or degradation of the fillings or crowns.

5. Clinical Considerations:

- While the occurrence of galvanic current is relatively rare with modern dental materials, it's something that dental professionals consider when planning restorations.

- Ideally, to avoid such reactions, the same or compatible materials are used for all restorations in one mouth, especially in areas where the restorations might be in close contact.

If a patient experiences discomfort that might be attributed to galvanic current, they should consult with their dentist. The dentist can assess the situation and recommend appropriate measures, which might include replacing one of the restorations with a material that is more compatible.