Many patients who want to replace their old silver fillings for tooth colored restorations, sometimes ask: “Which one is better?” This article intends to educate readers about composites or “white fillings”, and amalgams or “silver fillings”.
Dental amalgam, or “silver fillings”, has been used by dentists for the past 150 years. Dental amalgam consists of roughly a 50/50 mix of mercury and an alloy powder. Amalgams do last for many years, however they eventually allow saliva under them which produces cavities under the filling. Additionally, the tooth flexes around the amalgam during mastication causing small cracks that with time can result in fracture of the tooth. In this case, a crown is normally needed to protect the tooth from further fracture.
Amalgams are a good option for cases where esthetics is not a concern and it is not possible to bond a white filling. They are also less expensive than white fillings.
Composites or “white fillings” are basically a mix of polymers or plastic materials and fillers such as quartz, silica or barium. Composite fillings can be matched to the color of the patient’s own teeth. Composites require less removal of tooth structure because they are chemically bonded to the cavity preparation. Composite fillings have a natural, “white” appearance and can be repaired. However, they are generally more expensive than amalgams.
Are composite fillings weaker than amalgams?
In short, yes. The silver filling by itself is a stronger material, although it weakens the tooth. Composites strengthen the tooth because they bond to it, making the tooth more resistant to fracture.
“I would rather have a tooth that lasts in the mouth, than a filling that lasts in an extracted tooth”.
Silver fillings should be replaced if the tooth is susceptible to fracture or we suspect that there is a cavity under the filling. Silver fillings tend to hide cavities, which means that you may have a cavity under a silver filling and it may not show up on an x-ray. We recommend that patients get periodic dental exams and x-rays so we can detect cavities early and maintain your oral health.
Nowadays, most dentists prefer to place composites instead of amalgams because of the many advantages that composites offer to patients.