The literature suggests that a crown or bridge has an average lifespan of ten to fifteen years. However, it is common to see them last much longer than fifteen years. Crowns and bridges very rarely break. The main reason they fail is due to tooth decay developing on the tooth that holds the crown or bridge, similar to getting a cavity elsewhere in the mouth. This is why it is so important to clean around your crowns and bridges as well as possible to ensure they last as long as possible.