White fillings, also known as dental composites, are the most common filling placed today. Once the tooth has been prepared, a composite resin is molded and sculpted over an adhesive gel that is placed on the tooth. After the resin has been applied an ultraviolet light is used to harden the resin, which is then polished. Often, people refer to this process as bonding.
There are many advantages to tooth-colored fillings. One of the most obvious benefits is that these fillings blend in with the surrounding tooth structure for a natural appearance. Also, these fillings are bonded to the teeth which can offer support to a tooth that has been weakened by extensive decay and allows for attachment to areas with very minimal tooth support (such as chipped front teeth). White fillings can be used to correct cracks or gaps in teeth or to cover up stains or discolored teeth. These materials are made to more closely resemble the physical properties of your natural tooth so the expansion and contraction noted with silver fillings that can lead to cracks is not a concern here. Dental composites are also the filling of choice for when a more conservative preparation would be beneficial.
As with anything, there are a few disadvantages to these types of fillings. White fillings have the ability to stain and so, can discolor over time. They also require the area to be completely dry during the placement process, which can be difficult in a wet environment like the mouth.
Dental amalgams, or silver fillings, are a mixture of mercury, silver, tin and copper. Mercury is the binding factor which holds everything together to create a strong, durable filling. Dental Amalgam is a commonly used dental filling that has been used for over 150 years. It has several advantages over other restorative material, such as low cost, strength, durability, and bacteriostatic effects. They are also able to be placed in areas where moisture is a concern.
Amalgam is used in dentistry for a number of reasons. It is relatively easy to use and manipulate during placement; it remains soft for a short time so it can be packed to fill any irregular volume, and then forms a hard compound. Amalgam possesses greater longevity than other direct restorative materials, such as composite. On average, most amalgam restorations serve for 10 to 12 years, whereas resin-based composites serve for about half that time. However, with recent improvements in composite materials and a better understanding of the technique-sensitivity of placement, it should be noted that this difference is decreasing.
There are several disadvantages to these types of fillings however. Silver fillings can corrode and cause stains on your teeth and gums. Also, the shaping of the tooth cavity for placement of these types of fillings often requires additional removal of healthy tooth structure, making the filling larger than necessary and weakening the remaining tooth. With age, the metal of a silver filling expands, contracts, and can lead to cracks within your tooth. The larger the filling is, the more likely that this will occur. Finally, if you have allergies or sensitivities to metals you are not a good candidate for these types of fillings.
The American Dental Association Council on Scientific Affairs has concluded that both amalgam and composite materials are considered safe and effective for tooth restoration.