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Ceramic Fillings

An Evolution of Metal Restorations to More Biocompatible Restorations

Our mouth is a more complex system than we give credit for. It contains millions of microorganisms such as bacteria, yeast, and viruses; as well as enzymes and cells. It is under constant attack from acids, alkaline, food debris and other chemicals such as nicotine or alcohol.

Saliva contains multiple minerals such as chlorine, potassium, sodium and nitrogenous compounds.

Lastly, the mouth (and teeth) are subject to extremes of temperature – from drinking a cold drink to hot coffee and soup.

When it comes to placing dental restorations in the mouth, dentists are challenged to find a material that can withstand this onslaught of ?elements?.

Early history of restorations in dentistry involved gold – but this got too expensive and detrimental to the teeth as dentists had to ?hammer in? gold flakes. We then moved on to amalgams – due to the ease in placing them and the longevity of the fillings. Metals always had a place in the developing history of dentistry as it is a strong material, capable of being fashioned to fit the teeth and lasted a long time.

Or so we thought.

The advent of composites (polymer-based) and ceramics herald in a new era where these restorations could be ?bonded? to tooth – giving strength, longevity and was more pleasing to the eye (versus a metal filling).

And of course, we now know that it is also more biocompatible with the body. More BIOCOMPATIBLE, you may ask? Metals (and by that extension, alloys, which are a mixture of metals) are subject to corrosion. Corrosion is the gradual destruction of of a material due to chemical reaction with the environment.

This is of particular concern when metal fillings (amalgams), metal crowns (porcelain-fused-to-metal and gold crowns) and titanium implants are placed in a hostile environment provided by the mouth.

On face value, corrosion will affect the life and strength of the metal restoration, leading to fractures or failures.

However, one must also ask, what happens to the products of this corrosion? Indeed, corrosion results in the release of metallic ions i.e. mercury, nickel, chromium and iron – which may be absorbed by the body. Nickel for example, triggers an allergic response in the body. Mercury on the other hand, will be absorbed by the body and interfere with various biological pathways.

In the coming week, we will explore:

-what has been done to reduce corrosion of metallic restoration, and why it works?to a certain degree

-the effects of corrosion of metals on the body

-a rough estimate of the number of times your teeth meet in a year

-an example of why ?good enough? metal crowns are never ?good enough for us? at Image Dental.