A dental filling is required if you have a cavity in the tooth.
Sometimes there is enough enamel left on a tooth that it doesn’t need a dental filling and tooth reshaping can be used instead. Refer to the Tooth Reshaping section of this website for more information.
Often there is decay through the enamel and a filling is the best choice. In that case, we make the preparations as small as possible so that we leave as much of the tooth as is viable.
The dental filling material I use is a composite or 70%-80% tiny porcelain particles mixed in a light-cured acrylic resin.
I stopped using amalgam (silver/mercury) fillings in 1997. I don’t argue with people whether the silver/mercury composite is toxic or causes cancer. See next column for a description of the problems associated with the silver/mercury fillings.
I will remove the silver/mercury fillings if someone requests it. However, if someone doesn’t consume hot or cold food or drinks, these amalgam fillings may last 20 to 30 years.
Silver fillings have been used for 150 years. Dentists who still use these can point to a lot of research that shows that the silver fillings are not toxic to the body. While mercury is toxic, once it is incorporated into the silver, the research shows that the mercury doesn’t leach out.
The problem with the silver fillings results from the silver being combined with mercury. The mercury expands with heat and may cause the tooth to crack with exposure to hot drinks or hot food.
Mercury expands thermally much more than do tooth structures or other filling material.
Consider the fact that mercury is used in thermometers because it is so good at expansion.
With the example of a baking thermometer, you can see the mercury level change when you put the thermometer into something hot.
It’s my opinion that this same property causes the mercury in the filling to expand when you drink something hot.
When the tooth cracks, it will often cause the need for a dental crown.
An added risk factor is that amalgam is not a true solid. It doesn’t hold its shape; it moves under pressure.
When I was in dental school, we would have patients come in that had silver fillings that had been stable for 30 years with no decay but then we would see they had cracked; half the tooth had fallen off. It would always crack off exactly to the bottom of the silver filling. When I raised the possibility that the silver filling caused the cracking, teachers denied that possibility.
However, after seeing the effect of the tooth cracking at exactly the bottom of the silver filling thousands of times in my own practice, I’ve become convinced that there are better materials.