Choosing the Right Dental Filling – A Comparison of White and Metal Fillings
It is important for patients to be aware of the type of material being used in dental fillings because different materials provide different benefits. For example, white plastic fillings are usually more aesthetically pleasing and may provide greater longevity than silver amalgam fillings, which contain mercury and may require more frequent replacements.
The amalgam fillings (also called mercury filling) are silver in color and they tend to expand and contract based on the temperature conditions in the mouth. If you drink coffee or chew ice cubes, you subject your fillings to thermal stresses. The mercury expands and contracts differently than the tooth does and as a result, it can separate and cause micro-fractures between the tooth and the filling, also called a “leak” allowing for recurrent decay. Since these types of fillings are not “bonded” to the tooth, if they expand they could crack the tooth, or they could leave the wall of the tooth weaker and fracture under pressure.
On the other hand, white resin-based composite fillings are tooth-colored and blend in well with the tooth structure. The composite material bonds to the underlying structure of the tooth and strengthen and protects it. The composite fillings are also corrosion-resistant, and they tend to be less sensitive to hot and cold beverages. They are more suited for repairing front teeth where aesthetics is important. They also can be used when a corner of the tooth chips off and needs to be rebuilt back.
The white filling materials have come a long way since their original introduction into dentistry nearly 50 years ago. The bonding of the materials back when they originally came out, was not very good and they often fell out or stained quickly and were not very esthetic. Newer materials have significantly improved bonding capacity, better durability, and are more color stable. They are ideal in areas where the teeth show when you smile.
If esthetics were not a concern, when would we use a silver filling? If a child has a baby tooth that is going to fall out within a year or two and it has a large cavity, then placing a silver filling, might be an acceptable procedure. In addition, amalgam fillings can be placed in less-than-ideal conditions where access, moisture control, and tissue retraction might be a concern. If you get a small cavity at or below the gum line, if you wish to do a filling, it would be easier to simply pack a silver filling into that area, rather than trying to isolate the area, keep it dry, and then bond it into place, hoping it will stay in under compression and chewing.
What about gold fillings? When gold first came out, it was useful for small pits and could be tightly packed into a cavity and “burnished” at the edges. Some of these fillings lasted up to 40 years! With the improved technology we have with bonding and the fact that the price of gold has more than quadrupled, it is not used anymore as a restorative material except in rare cases.
CONCLUSION: The material that we use to restore a tooth has several factors that go into deciding which material to use. As a result, some materials may not be suitable for certain dental procedures and may require more specialized care. Therefore, it's important to speak with your dentist and learn more about the different types of materials available to make sure you are choosing the right material for your individual needs. Dr. Craig Mitchell in Cupertino, CA has been taking care of patients for over 30 years and can help you decide which material is best for you!