If a person has many fillings, their teeth can look like a vein of silver in a mine in Park City, Utah. But, while those fillings may look like silver, they’re called amalgam, and it’s been the filling material of choice for over 150 years. But thanks to the increasing quality and strength of composite resin, not to mention that composite fillings are virtually invisible on the tooth, Dr. Steier is placing composite fillings whenever possible these days.
What is dental amalgam?
Dental amalgam has been the filling material since the 1800s. Imagine just how many teeth have this silver metal mixture in them! Dental amalgam is a mixture of metals consisting of liquid (elemental) mercury and a powdered alloy composed of silver, tin, and copper. Approximately 50% of dental amalgam is elemental mercury. The chemical properties of elemental mercury allow it to react with and bind together with silver/copper/tin alloy particles to form an amalgam. Ouch! Who knew you had half the metals from the Periodic Table in your fillings! But despite the sound of the toxic mix of amalgam fillings (actually they are very safe), the reason they’ve been used for so long is their strength.
Composite fillings to the rescue
Composite fillings are rapidly taking the place of amalgam. Composite resin is a mix of tooth-colored plastic and glass. When they are placed into a tooth, they are virtually invisible. This is a far cry from the big hunk of silver/mercury for all to see with an amalgam filling. The problem with composite resin has been its strength — composite hasn’t been as strong as amalgam. Think of Captain America versus Superman. But that has been changing and quickly. Recent advances have dramatically strengthened the composite material used for tooth-colored fillings. Now composite can be used for fillings in the molars with confidence. The new composites can handle the extensive bite force generated by the molars; that’s why Dr. Steier places mostly composite fillings these days.
How composite fillings are placed
Composite fillings are placed in a process more akin to dental bonding than to the way amalgam fillings were placed. After she cleans out all the decay from the tooth, Dr. Steier begins placing the composite resin into the space left by the now-removed decay. This is done in a layering process. Once she applies a layer of composite resin, it is immediately hardened using a “curing” light. Then the next layer is applied in the same fashion, continuing until the height and shape of the filling match the desired shape.