When cavities severely damage teeth, dentists quickly try to treat the affected area to prevent further decay by drilling and filling teeth. There are many options for filling materials, but amalgam and composite are the most common. While both materials are widely used, their differences in durability, cost, aesthetics, and safety make each better suited for different patient needs.
Amalgam
Amalgam is also known as “silver filling.” However, its common name does not accurately reflect its composition: the material is primarily composed of liquid elemental mercury and a powdered alloy mixture of silver, tin, and copper. The affected area is first drilled, and a metal mixture is prepared into a putty-like substance. Following the filling preparation, dentists fill the drilled tooth and let it harden in place. The metal mixture filling is typically used for patients who are more prone to developing cavities, have large cavities, or have dry mouths.
Composite Resin
Unlike amalgam, composite resin, which is also known as “white filling, is made of acrylic plastic and finely ground glass particles. Similar to amalgam, dentists first use a drill to remove the decayed portion of the tooth before making the tooth porous by etching, increasing surface roughness and allowing the adhesive to bond more effectively. After etching, dentists add composite resin in layers, using a curing light to solidify each one. Finally, the tooth with composite resin is polished. Composite resin filling is typically used for patients who have small cavities.
Advantages and Limitations
Amalgam filling is cheaper than composite resin filling, costing from $200 to $400 per tooth compared to $215 to $500 per tooth. The metal mixture filling is also more durable than composite filling: amalgam fillings are predicted to last twelve years, which is more than double the five year longevity of a composite resin one.
Although amalgam offers advantages in cost and durability, amalgam requires controlled moisture conditions during placement for the materials to properly set. For those who produce much saliva in their mouth, amalgam fillings might not be best suited for them. Additionally, there are many concerns regarding potential mercury toxicity and safety. Consequently, composite resin is often perceived as a safer alternative.
Besides being the seemingly safer option, composite resin is more aesthetic, as its white appearance blends better into the teeth than amalgam. Composite resin is also known to be associated with temporary temperature-sensitivity, causing only short-term discomfort.
Safety Concerns
As previously mentioned, there are a number of concerns regarding the safety of having amalgam as a filling. Some concerns suggest that mercury vapor may be released when a tooth containing the filling is chewed on, resulting in heavy metal build up called bioaccumulation. Young children and expecting mothers may be at higher risk for mercury bioaccumulated toxins. However, both the Food and Drug Administration and the American Dental Association deem amalgam fillings safe, as more studies found no significant negative health effects.
There are also environmentalists who are concerned about the environmental implications of amalgam fillings, specifically the waste disposal after the procedure. Dental offices who improperly dispose of mercury-based filling may seep into the environment, vegetation, and waterways. For this reason, dental offices are required to dispose of their waste through a filtration system.
Conclusion
Amalgam and composite resin fillings are both commonly used to treat decayed teeth. Each material has its benefits and drawbacks in costs, durability, aesthetics, and potential safety concerns, but both are deemed safe by governmental and national organizations. Ultimately, the choice between amalgam and composite resin depends on clinical needs, patient preferences, and long-term considerations rather than a universally superior option.
