Galvanic pain (also called galvanic shock), is an unusual type of dental pain caused by an electrochemical circuit formed when adjacent or opposing dental restorations made of dissimilar metal alloys (e.g. amalgam and gold) come into contact in the presence of saliva. When the metals contact, saliva can act as an electrolyte, creating a galvanic cell and causing galvanic corrosion of the metals to gradually take place, and a sudden, small amount of electric current is generated, flowing through oral tissues and stimulating the nerves in the dental pulp.
There may also be a metallic taste in the mouth due to release of metal ions. Placing a layer of rubber (e.g. a dental dam) between the dissimilar metals and observing if the pain is gone is diagnostic for galvanic pain.
Prevention and management
The placement of dissimilar alloys in teeth where they will be in continuous (e.g. adjacent) or intermittent (e.g. opposing) contact is not advised by some, while others advise to use a cavity lining underneath the metallic filling in situations where there will be contact with a dissimilar metal. Long term galvanic pain is unlikely because polarization will likely occur, or corrosion products will coat the external surface of alloy and act as an insulating layer against further galvanism. Others therefore argue that because galvanic pain is generally short-living and self-limiting, concern about galvanic pain should not factor into the clinical decision of what restorative material to use. The treatment depends upon the level of pain. If there is minimal pain, then the dentist typically just waits to see if the situation will resolve itself.
Treatment of galvanic pain which is severe or does not resolve by itself may include placing a layer of varnish, resin, or non-metallic restorative material over the offending metal to break the contact between the dissimilar metals.
- Soratur, S.H. (2002). Essentials of dental materials (1st ed.). New Delhi: Jaypee Bros. Medical Publishers. pp. 50,100,101. ISBN 9788171799893.
- Davis, edited by J.R. (2003). Handbook of materials for medical devices. Materials Park, OH: ASM International. p. 224. ISBN 9781615032594.
- Williamson, R (Jan–Feb 1996). "Clinical management of galvanic current between gold and amalgam.". General dentistry 44 (1): 70–3. PMID 8940574.