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  • Dr. David Alfaro

Metal vs Plastic Fillings

dr david alfaro, prosthodontist, vancouver dentist, richmond dentist, fillings, cavities, tooth pain, pizza, beer, bieber

What is the deal with metal fillings? Are they bad for you? What about plastic ones? Do they not last as long as metal fillings?

These questions are often asked by dentists and patients alike, and to be honest, the information that we have available to us is quite difficult to analyze. To understand the data, we need to first know a bit of background.

First of all tooth decay has to be diagnosed for a tooth, which is what most people call a "cavity". The dentist then drills away the decayed parts of the tooth, and places a filling in the cavity that is left. But.......what type? Well, there are metal fillings and a couple of different types of plastic fillings and they all have advantages and disadvantages.

Amalgam (metal) fillings have been around for over 150 years and are still in use today. The filling material is composed of a mix of silver, tin, copper and other trace metals. In order to make the material malleable, mercury is shaken in to the metal mixture. This semi-liquid metal mush is then crammed in to the cavity and hardens over the next 24 hours. Yes, there is mercury, but much of this mercury is removed during the filling process as it is compressed out and removed via the suction wands as the dentist shapes the restoration. These fillings do not stick to the teeth so the dentist has to cut the tooth into a shape that allows for the restoration to lock in place after it sets.

Composite (plastic) fillings have only really been around since the 1980's. The material itself does not stick to the tooth, but an adhesive can be applied to the cavity which allows for the plastic to be bonded in place. The dentist therefore often only has to remove the decay, and does not need to cut the tooth in to a specific shape to lock the plastic filling in place. The material is placed in as a paste and then is hardened with a blue light, which can cause the material to shrink a bit. It is much more technique sensitive in comparison to amalgam, and the quality of the filling is affected by many more variables.

Many people come in asking to have their metal fillings taken out because of the mercury, but guess what? Plastic isn't necessarily the best either. So what to do????

There is too much information to go over in one post so I will be putting up a series of articles and videos.

Check out these vids for more information:

Dental Amalgam:

Dental Composites:

Thanks for following along!

Dr. Dave

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