Amalgam vs. Composite Resin Fillings

Your body has an amazing ability to repair and heal itself. As an example, when you break a bone, your body can create new cells that glue the broken bone back together. However, the body’s ability to repair itself doesn’t include your teeth. Once you injure a tooth or develop a cavity in it, your body can’t repair the tooth itself.
If you do develop a cavity in one of your teeth, your dentist can provide you with a range of options to repair and fill the problem tooth. In this blog we’ll just focus on the two most popular common fillings, amalgam and composite resin.
Amalgam Fillings
Most people know amalgam fillings as silver or mercury fillings because they are made from silver, copper, tin, zinc and mercury. They’ve been used by dentists for nearly 200 years. When combined, the metals initially produce a soft material that the dentist uses to fill your tooth. Quite quickly, however, the metals harden as they combine. Multiple studies have shown that amalgam fillings are safe. Although pure mercury is toxic, the mercury found in amalgam fillings is locked inside when the filling hardens and is therefore not harmful.
Composite Fillings
Composite resin fillings are also called white fillings, tooth-colored fillings or direct veneers. They are made my using bits of silica and covering them with a plastic resin compound. This is a newer approach to fillings used by dentists, and the technology is constantly improving. When a dentist fills a tooth with a composite filling, it has the consistency of modeling clay until a bright blue light is shined on the filling by the dentist. A series of chemical reactions hardens the composite resin into a sturdy material that resembles your natural tooth.
How Do You Decide What to Choose?
Here’s a list of nine factors you should consider when deciding on whether you should get an amalgam filling or composite filling.
1 Amalgam fillings are stronger than composite fillings. Amalgam fillings are often used on the back teeth because of their strength. Your back teeth absorb the most force when you bite down and/or chew.
2 Composite fillings are more expensive than amalgam fillings. If you’re on a tight budget, amalgam may be your best choice.
3 Amalgam fillings last longer than composite fillings. Eventually, composite fillings will last as long as amalgam. But that time isn’t here yet, so if you want your filling to last a long time, pick amalgam.
4 Composite fillings are less noticeable than silver amalgam fillings. Most people won’t notice an amalgam filling on your back teeth. But if you don’t like the look of silver, go with composite.
5 Amalgam fillings contain mercury. It is true small amounts of mercury are released by amalgam fillings but it’s less than you get from eating fish. However, if you are allergic to mercury, an amalgam filling could be a problem.
6 Composite fillings may leak out Bisphenol-A. In large enough doses, the chemical bisphenol-A can be toxic. However, studies have found that the amount of Bisphenol-A released from a filling is unlikely to cause any harm.
7 Amalgam fillings require the dentist to remove healthy tooth structure. Since amalgam fillings don’t bond to the tooth like composite fillings, the dentist has to make the filling wider at the bottom than it is at the top so that the tooth will hold the filling in place. In order to do this, the dentist usually has to cut away healthy tooth structure. With composite fillings, the dentist can simply remove the decay and then place the filling without cutting away healthy tooth structure to retain the filling.
8 Composite fillings shrink when they harden. Most composite fillings get somewhere between 2-5% smaller when they harden. Sometimes this can lead to gaps between the filling and the tooth which allow bacteria to enter and start a new cavity. Other times, when a large composite filling shrinks as it hardens, it can put stress on the tooth which results in increased sensitivity of the affected tooth. The effect of the shrinkage can be minimized if the dentist adds the composite in small, incremental layers.
9 Composite fillings are more technique-sensitive. This means that the dentist has to pay close attention to detail when placing a composite filling. For example, if your dentist doesn’t properly prepare the tooth with an etching solution for a specific amount of time, or if they do, but some of your saliva gets onto the tooth after it is etched, the filling may not attach to the tooth tightly and could end up leaking and ultimately needing to be replaced after only a year or two.  Our dentists have lots of experience doing white fillings and will do a good job.
Give us a call to discuss any questions you may have about amalgam vs. composite resin fillings. We would be happy to answer your questions and give you additional information.
Source: WebMD, DentalFearCentral.com