Which filling material is best for my teeth?

Thursday, December 12, 2015

There are many choices for dental “fillings” – the material used to restore your teeth when or if you get a cavity.

A filling is designed only to ‘fill’ a cavity and to seal off further invasion by bacteria. Contrary to what many people believe, fillings don’t strengthen or repair the tooth in any way.

Each filling material has its pros and cons. Advances in technology, as well as shifting priorities for consumers, have driven preferences for different materials.

Ideally, dental filling material should have the following qualities, in order of importance:

  • Dimensional stability (doesn’t change shape over time)
  • Physically strong (is able to resist wear and breakage)
  • Cosmetically appealing (looks like a tooth)

I think it’s important to know the differences between the types of filling materials. That way, if you need a restoration, you’ll understand how each material will behave, how long it will last, and how it will look.

Dental amalgam

Dental amalgam gets a bad rap. People are concerned that the mercury in the amalgam material will enter the bloodstream (although the mercury levels detected have never been proven to cause illness). Most people don’t like the way it looks either, as its dark colour contrasts strongly with the natural colour of the tooth.

The main reason dental amalgam is bad for your teeth however, is because the material is not dimensionally stable and continually expands with time.

I’ve found in my practice that nearly all large amalgam restored teeth fracture over time, and sometimes to the point where the tooth to split beyond repair. This, coupled with newer restorative materials, is why we don’t use amalgam at Oasis Dental.

Composite resin

Did you know that what is commonly referred to as ‘white’ fillings is a plastic material? The technical term is composite resin and this material is dimensionally unstable – it doesn’t maintain its shape.

When a dentist places a composite resin filling in your mouth it’s in putty form, or a semi-liquid. It is then cured with a high-intensity blue light, and the putty solidifies and hardens.

This process is called polymerisation and with it comes shrinkage – the filling becomes smaller than the cavity it sits in.

Dentists strive hard to reduce this shrinkage but it’s what causes the decay to come back. The primary goal of the filling, the seal, is compromised over time and bacteria gets back in.

It’s not long, in my experience around 2-7 years later, before you need another filling in the same tooth –– but this time a little bigger and a little bit deeper. This causes damage even faster than the old amalgam fillings took to break your tooth.

Porcelain

In my opinion, porcelain (sometimes called dental ceramics), is the best filling material you can use for a restoration. If well-looked after following treatment, it will restore your oral health for the long-term, decades even, with good care. It’s also the most cosmetically appealing of all the materials.

Because it’s designed precisely to fit your tooth, made outside the mouth, then glued in, there is no opportunity for shrinkage as with plastic fillings.

The downside is it is that porcelain is not cheap and these fillings take longer to make.

Porcelain fillings are made outside of the mouth, either by a dental technician or CAD-CAM (Computer Aided Design – Computer Aided Manufacturing) system, and then cemented in. This new technology means that porcelain restorations can be made and cemented during the same appointment – so less time and less injections.

Not all dental practices have access to a CAD-CAM, but at Oasis Dental we have not one, but two!

Gold

Before the introduction of dental porcelain the best restorative material was gold. It has similar qualities to porcelain, in that it’s very stable and very strong.  However as the price of gold increases each year, it is expensive to manufacture and because it looks ‘gold’ it lacks the cosmetic appeal.

Unlike porcelain, gold restorations have to be done over two appointments and are made by a dental technician, so it is also less convenient.  For these reasons, it’s rarely used today, but occasionally it is used when really high strength is required.

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