Should I replace my silver fillings with white fillings?
Many patients want to replace their old silver fillings for white, natural looking restorations, and many patients also ask, “Which one is better?” This article seeks to educate patients about composites or “white fillings” and amalgam 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, usually composed of silver, zinc or palladium. It has been the most tested dental material to date. Recently, its safety as a filling material has been questioned due to its mercury content. Many people believe that the mercury contained in the amalgam is toxic and could cause several health issues. Whether or not this amount of mercury is harmful to the body is a subject of controversy. Most people have some silver amalgam fillings in their teeth with no apparent adverse effects. No harm from the mercury in amalgam fillings has ever been absolutely proven.
Additionally, once the silver filling is placed by the dentist, the patient has to wait 24 hours to eat on that side of the mouth, otherwise the filling could crumble and break. It is well known that amalgams do last for many, many years. However, after many years of the silver filling being in your mouth, they allow saliva under them and can corrode. Also, the tooth flexes around the amalgam during mastication, causing small cracks that with time can cause breakage within the tooth and finally it can fracture the tooth. Generally, after a large silver filling breaks, the tooth needs a crown in order to protect the tooth from breaking further.
Amalgam fillings have a dark, gray appearance and many people do not like the look of their mouth when they smile or talk. Amalgams are a good option for cases where esthetics is not a concern and it is not possible to keep the area dry in order to bond a white filling. They are also generally less expensive than white fillings.
Composites or “white fillings” are formed from polymers, forming a hard plastic. The term “composite” means “made up of distinctparts or elements”. Therefore, a composite filling is basically a mix of polymers or plastic materials and fillers such as quartz, silica or barium. These fillers provide the strength to the composite material. Composite fillings come in a variety of colors, so they can be matched to the color of the patient’s own teeth. Composite fillings also lend strength to the tooth, whereas amalgams don’t.
After the filling is light cured in the tooth, the patient can eat on it right away, since the material is completely set by the light, while the patient is in the dentist’s office. Also, composites require less removal of tooth structure because they are chemically bonded to the cavity preparation essentially splinting the tooth together. Because of this fact (chemical retention), we only remove the decayed portion of the tooth. This is in contrast to silver fillings, in which more healthy tooth often has to be removed in order for the amalgam to mechanically stay in place.
Composite fillings have a natural, “white” appearance and many people prefer the look of their mouth when they smile or talk. Composites are an excellent option for cases where esthetics is a concern and it is possible to keep the area dry in order to bond a white filling. However, they are generally more expensive than amalgams.
Are composite fillings weaker than amalgams?
In short, yes, they are. The silver filling by itself is a stronger material, although it weakens the tooth. If you look at the total result — the filling plus the tooth —composites are stronger because they bond to the tooth, making the tooth more resistant to fracture while old amalgams tend to break the tooth. I would rather have a tooth that lasts in the mouth, rather than a filling that last in an extracted tooth.
I’ve heard I should get my silver fillings replaced. When is this a good idea?
We recommend replacement of silver fillings when the tooth is susceptible to fracture and when we suspect that there is a cavity under the existing filling. This can occur most commonly in old silver fillings. Silver fillings tend to hide cavities, which means that you may have a cavity under a silver filling and it will not show up on an x-ray. That is why we recommend that patients get periodic dental exams and x-rays so we can detect cavities early and maintain your oral health.