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Metal Crowns

Why ?good enough? metal crowns to some are ?never good enough? for us at Image Dental?

Metal crowns almost always have amalgam beneath it as it acts as a build-up to support the crown.

Amalgam was traditionally used because there was no other alternative material with sufficient strength to stay in place. Our gripe with metal crowns are three-fold: The amalgam beneath the crown – amalgams are never a good idea. It is even in the manufacturer?s instructions to never use amalgam as a core build-up under a crown.

However, this is widely done because of convenience, cost, time etc. Our other concern too is of chronic mercury toxicity where there is build-up of mercury in the tissues and organs which disrupt the normal biological processes.

The amalgam-metal interface – two different metals, in a moist environment is a recipe for a CAR BATTERY. When you have amalgam beneath the metal crown, it causes corrosion. On top of that, some people may experience GALVANIC PAIN due to a ?current? flowing between the two different metals through the moist environment.

Other complaints include a metallic taste in the mouth, or tingling and burning of the tongue. Metal crown – metal crowns are made up of a few different metals. Even the best metal crowns with passive layers will corrode slowly inside the mouth due to the presence of a moist environment (saliva).

Over time, the margins of the crown will leak, allowing decay to spread beneath the crown. This decay is sometimes hard to pick up because it cannot be seen with the eyes and does not show up on X-rays.

Also, the corroded metal will stain the teeth, leaving the margins dark and black.

A patient came in with concerns regarding a failed root canal treatment of the central incisor. The patient opted to extract the tooth as it was continuously causing problems. After the extraction, we did an experiment with the extracted tooth with a porcelain-fused-to-metal (PFM) crown. We drilled the crown of the central incisor and removed the crown. What was below the crown? We found an AMALGAM CORE beneath it. Also, note, the black margins that circle the tooth – a classic example of corrosion staining of the margins.

The photos below illustrate the findings. What we are trying to say is that, if you have metal crowns in the mouth, it is worth considering changing them for the risks they pose. We recommend replacing them with all-ceramic crowns, which have no metals in them and are more biocompatible in the mouth.