Dental restorations that bond directly to the tooth can last as long as traditional restorations, which do not. Older restorations that contain metal include amalgam fillings (made of silver, tin and mercury) and fused metal crowns. Composite fillings have many benefits including their aesthetics, being mercury free, and less of an impact on the surrounding tooth structure for them to be placed. In the case of very large fillings needing to be placed, larger composites fillings can outlast the life span of large amalgam fillings. (1) Composite fillings bond directly to the tooth structure so rather than filling a cavity, they are essentially recreating the tooth structure of that area. Amalgam fillings are simply wedged into these areas, and when they run out of tooth to hold them in, they can cause fractures to the enamel and fall out.
When a tooth requires a filling that is too large, a crown is placed on the tooth. This recreates the area of the tooth above the gumline, so that the entire tooth can be kept as long as possible. Because it covers the entire surface above the gums, it can also withstand normal use without compromising the stability of the remaining tooth structure. While tooth colored crowns have been around for several years, the older ones were fused to a metal base and then the metal surface was cemented onto the prepared tooth. Newer crowns can be fabricated entirely out of tooth colored porcelain structure, and then bonded directly to the tooth.
In the past whenever gums receded away from a crown, the metal base would show as a dark line against the tooth. Likewise, if ever a small sliver of porcelain came off of a fused metal crown, the underlying metal would show through. Because fused metal crowns are fabricated in a laboratory at high temperatures, there was never an option to correct these aesthetic problems inside of the patient’s mouths. The only option was to wait until the life of the crown elapsed and then replace it entirely. Newer composite and resin crowns are now made entirely of porcelain. There is never a risk of having underlying metal show again.
Patients are choosing metal free restorations for a variety of reasons. Whether it’s because they are more aesthetic, the low impact that they make on your teeth, or that they do not contain mercury, the choices and benefits are great. Silver fillings have been used in dentistry for over a hundred years, but that doesn’t mean we need to keep using them. There are more beautiful options available to dental patients such as direct bonded composite fillings and crowns.