Many people have concerns and fears over the safety of mercury amalgam fillings.

You may already know that amalgam fillings are made up of mercury, silver, tin, copper and zinc - and if you don't then take a moment to think about that!

Mercury comprises up to 50% of the amalgam filling. As such Waiheke Dental Centre has, since 2011 only placed mercury amalgam at patient request and in 2013 stopped placing them completely as new data on the effects of mercury amalgam fillings was learned.

At the Waiheke Dental Centre, we value your health as much as you.

For this reason we want to remove your old amalgam fillings as safely as possible. We remove them under the protection of rubber dam, in addition to our standard routine of copious water spray and high volume evacuation of the contaminated water and mercury vapour.  (Rubber dam is a rubber sheet approx. 15 cm square in which we create a hole just big enough to expose the affected tooth /  teeth we need to see to complete the Amalgam removal. The dam placed over the teeth, means any contaminated water and amalgam debris can be removed without issue. Your other teeth, tongue, gums and throat are on the other side safe from the debris. Also no worries about the water in your throat!)

For over a decade a growing number of my patients asked us, for various reasons to have their mercury amalgam fillings removed & replaced with bonded, tooth coloured, non metallic restoration - usually white composite resin fillings or porcelain crowns.

mercury removal and replacement

Over this time, the tooth coloured composite resin filling I was using and the techniques to actually strongly bond the tooth together had been improved to the point where, I believe, it was a better filling material than mercury amalgam. As a consequence of this I would remove the old mercury amalgams & replace with a tooth coloured filling or porcelain crown/overlay. Worryingly, I would find, in about 50% of these old amalgams either undiagnosed decay or an undiagnosed crack in the tooth or both.

Now, over a decade later all those old mercury amalgam fillings are even older & almost every one I remove that is a medium sized or bigger has decay & or structurally bad cracks/fracture lines in it. Often these mercury amalgam fillings were placed in childhood or early teens so some of them are 20 to 40 odd years old (or even older). They are well past their use-by date!

How teeth with mercury amalgam fillings behave together

These old amalgams are not actually attached to the tooth – they just fill the hole.

When the amalgam filling heats up (eg when you have a hot drink) the metal, especially the mercury, expands (think mercury in a thermometer). This expansion puts stress on the enamel cusps over and over again. Eventually years later the cusps develop stress fractures & crack. Sometimes the cusps crack off above the gum line. Sometimes the tooth will crack below the gum & need to be extracted

When the amalgam filling heats up & expands (eg having a cup of tea) & then cools down contracting (eating ice cream) gaps open up around the filling.

There are now machines designed to mimic the forces exerted on teeth during ordinary chewing. When an extracted tooth, which has a medium sized mercury amalgam filling, is placed in this chewing machine, the tooth twists, bends & flexes. The cusps on either side of the amalgam filling move independently as the mercury amalgam filling does not bond, glue or hold the tooth together.

The amalgam filling also moves. If the amalgam filling is now removed & a white composite resin filling is bonded in to the same cavity the amazing properties of composite resin fillings can be seen. When the tooth is put back in the chewing machine & the same forces are applied the tooth & white filling twist, bend & flex fully 26 times less than the the same tooth with the mercury amalgam filling.  Essentially replacing mercury amalgam fillings with white composite resin makes the tooth stronger. Almost as strong as the tooth was before it decayed.

Learning about biomimetic dentistry was a real turning point for me. Biomimetics means life like. An American dentist called Dr Dave Alleman pioneered with his colleagues the chewing machine described above to illustrate the benefits of bonded composite resins. He then created a way of strongly bonding white composite resin to the tooth to recreate the join between enamel and dentine.

Following this bonding process, I can now bond white composite resin into cavities that almost mimics how the original tooth was prior to it decaying, increasing the tooth strength a long the way. Dave was also instrumental in creating a protocol to bond a very strong fibrous mat into the composite resin filling. I use this mat (called Ribbond) to bond tooth fractures together. It is incredibly strong – it is similar to the Kevlar found in bullet proof vests.

If you have concerns over your health with regard to your amalgam fillings then we can discuss with you at a consultation how we can safely and easily remove these fillings. We can then reconstruct your teeth using metal free alternatives, such as:

*  porcelain CAD/CAM overlays, onlays or crowns

*  tooth coloured composite resin fillings or restorations

Further to this we can  help you with complementary measures such as supplementary piped oxygen plus high dose vitamin C and mercury elimination medicine protocols.