Composite Bonding & Amalgams

Composite Restoration Fillings

Composite fillings in natural tooth-colored resins are used to replace a decayed, chipped, or fractured portion of a tooth.  These can be shaped on a tooth in the mouth directly, or can be glued into a tooth after the filling has been prepared in a lab. This composite material is a cost-effective synthetic glue which most commonly is a Bis-GMA or mixture of dimethacrylate monomers (TEGMA, UDMA, HDDMA) with silicate glass filler material.  Before hardening, composites taste and smell like strong chemical glue; but this dissipates quickly as they contain a photoinitiator which allows the material to harden (by polymerization) in blue spectrum curing light. 

Items using these composite materials are found in plastics ranging from the coffee lids at Starbucks to the windows, walls and chair frames on the airplanes manufactured by Boeing.

Amalgam Restoration Fillings

Silver-colored metal dental fillings are often an amalgamation of a silver alloy which can be prepared during a patient’s appointment and directly packed into the empty spaces remaining in teeth after cavities have been removed.  This kind of restoration treatment can usually be completed during one appointment with the dentist.  Amalgams have no taste; and when inserting these restorations in the mouth, the excess material may feel like stale graham cracker crumbs until they are easily cleaned up.

A Brief History of Amalgams

The first dental amalgams document back to the Tang Dynasty in 659 AD and were used in dentistry in Germany as early as 1528. Through the 17th century, mercury became known to relate to “Mad Hatter’s Disease” (mercury poisoning due to its use in making hat felt which was observed to cause eccentric behavior in hat makers). Over the years, amalgam alloys used various amounts of mercury acting as a glue for mixtures with different percentages of fillers including silver, tin and coper. In the ensuing centuries of dental developments, the safety of amalgam fillings greatly improved.  As long ago as the 1980’s and through the present, amalgams are often the material of choice for fillings (to fill the spaces in teeth after cavities caused by decay have been removed) due to their low cost and long-term durability.