White Fillings

Silver fillings vs White fillings

There are many different types of filling materials available today, each with its own set of pros and cons. As with most medical interventions, there is no one-size-fits-all approach, and your dentist is trained to use a broad range of materials, selecting the best one for the job at hand.

Generally-speaking, however fillings can be divided into two broad groups: silver or amalgam fillings, and tooth-coloured fillings or composite resins.  

So what is dental amalgam?

Amalgam is a mixture of metals including silver, tin and copper with a wetting agent, namely mercury. When mixed this creates a mouldable mass which can be packed into a defect prior to setting.

Dental amalgam has an excellent track record in spite of toxicity scares. Silver fillings last on average between 12 and 15 years.  

Their advantages are:

Low technique sensitivity (i.e. Less dependent on the dentist’s skill)

Easy to see on X-ray

Strong

Durable

Easy to differentiate from natural tooth structure

Their corrosion results in good a marginal seal

Disadvantages of silver fillings, and the reasons we, at Family Dental Centre no longer use them are:

Poor cosmetic appearance

The need for increased tooth structure to be removed during placement (silver fillings do not bond directly to the tooth and so the cavity must be designed to give a mechanical ‘lock’)

They conduct temperature readily – can cause sensitivity

Expansion and contraction of the metal can lead to the tooth cracking

It is difficult to spot early decay underneath a silver filling because they reflect almost all x-rays and can mask signs.

Toxicity:

There have been myriads of studies done on dental amalgam toxicity and literally billions of amalgam fillings placed. There is no study which has shown conclusively that amalgam fillings cause mercury poisoning. In fact, we ingest more mercury in our diets than gets released by silver fillings. Most of the mercury is removed during placement, leaving the dentist at higher risk of poisoning. Dentists have been placing silver fillings for their entire careers (many without gloves!) and they have not suffered any adverse effects. We at Family Dental Centre practice evidence-based dentistry, and the scientific evidence has shown that silver fillings are quite safe, and do not result in mercury poisoning.  

So what are tooth-coloured fillings, and why are they so popular?

Composites are a mixture of resin and a particulate filler substance such as quartz. These can be manipulated, moulded and cured (made hard) by a high frequency light. Composites are much newer than amalgam, and in the last two decades their technology has advanced exponentially, making them the filling material of choice for most dentists today. Results from longevity studies vary, but at Toothpals, we have seen many of our own composites survive 10 years and more. With a good dentist, careful oral hygiene and regular checkups composite fillings last extremely well. 

The advantages of composites are:

Great cosmetic appearance

Can be mixed and manipulated to be almost indistinguishable from natural tooth structure

Similar hardness and expansion to the natural tooth

Bonds directly to tooth structure so minimal drilling is required

A leaking margin is easy to spot

They are poor conductors of temperature – resulting in less sensitivity to hot and cold

Easy to asses on X-ray – leaks are not masked

Some composites leach fluoride which protects the tooth against further decay 

Disadvantages:

Highly technique sensitive

Moisture sensitive during placement

Must be placed in incremental layers

In conclusion, we at Family Dental Centre prefer composite resins, and are very experienced in working with them. We continue to assess and maintain silver fillings but do not place them because of their tendency to crack teeth over time.   

Should you remove and replace all of your silver fillings?

Not necessarily. Your dentist will alert you to cracks in the teeth where it may be prudent to replace the silver filling with a white one, but some silver fillings are doing a great job, and should be allowed to continue to do so. If you are concerned about the cosmetic appearance of your silver fillings, speak to your dentist, and he would be happy to advise on your options for improving your smile. 

1. Mitchell. Oxford Handbook of Clinical Dentistry 5th Ed. 2009

2. Soares, Cavalheiro. A Review of Amalgam and Composite Longevity of Posterior Restorations. Revista Portuguesa de Estomatologia, Medicina Dnetaria e Cirurgia Maxilofacial. Vol 51. No.3. 2010

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