Amalgam vs. Composite

Author: Dr. Alison Vitelli, DMD

As was discussed in Dr. Dickerhoff’s previous blog, you have different options of restorative materials when getting a filling placed on a tooth. These could be tooth colored (composite) or silver fillings (amalgam). Both are proven to be great restorative materials, but they shouldn’t be just a simple choice of esthetics or cost but rather as which one would have a better longevity.

The physical and chemical properties of both materials are very different. The silver filling (amalgam) is a metal alloy that is retained on the tooth by basic mechanical retention design of the preparation, whereas the tooth colored filling (composite) rely on a bond with the tooth structure after a chemical process known as polymerization. This is activated when we “shine the light” on your tooth when placing the composites.

Composites require a dry environment for better results and lower recurrence of decay. As a general protocol, we would restore a tooth in the anterior area with a composite. The main reason is esthetics! I think we all will agree that we don’t want a dark filling on our front tooth but it is also easier to isolate the area and keep it dry as opposed to a molar. Therefore, we must use a dental dam or a lot of cotton isolation, so the area does not get contaminated by saliva or blood. It has been stated, if we encounter a cavity that is below the gumline it becomes a challenge to keep blood and fluids from leaking to the dry environment required for the chemical bond to form with the tooth. Amalgam would then be a preferred material for a case like this due to being more forgiving in an environment in contact with the gum. At a microscopic level, composites are more porous as opposed to amalgam which offers a smoother surface making it harder for bacteria to adhere.

The physical properties of a metal alloy such as amalgam (silver, tin and mercury) allows it to withstand the forces of the human bite a lot better than some of the composites. Technology has progressed to a point where the composites have been designed to have strength and flexibility values closer to that of tooth structure.

At Spring Lake Dental Group, we strive to provide you with the best treatment to every one of our patients. So next time you have an appointment, let us know your questions. We look forward to talking to you and to educate you about your options!