TOOTH-COLORED RESTORATIONS (Composite)

What Are the Advantages and Disadvantages of Composite (white) Fillings?

Many people ask us why we do all of our fillings on back teeth using composite (white) fillings rather than silver amalgam.

Silver amalgam is composed of silver, copper, tin, zinc and mercury. The mercury is what allows the formulation to be in a putty-like consistency while it is placed in the tooth, and then harden to a metal consistency. Amalgam has been the filling of choice for about a century. It's advantages include: strength, durability, low cost, and ease of placement.

An amalgam can be contaminated by saliva or blood during placement, and it's longevity will not be affected. Amalgam's disadvantages include: undesirable esthetics (they start out silver/gray and end up black with age), lack of bonding, frequency of tooth fracture, and some concern about mercury toxicity (although this has never been proven scientifically).

Composite fillings are very different from amalgams in many respects. They are made from a plastic resin with varying amounts of glass fillers, depending on the brand. Composites have been in use since the 1960's, but were initially used only for front teeth.

What sets composites apart from amalgam is that:

1-They are tooth colored.

2-They are bonded to the tooth. This is the most important feature of composite fillings, and the one that has caused such a revolution in dentistry.

The composite is microscopically attached (bonded) to the tooth by a 3 step process. First, the tooth is treated for 15 seconds with a mild acid. This conditions or "etches" the tooth. It provides microscopic irregularities in the enamel, and opens small tubules in the dentin of the tooth.

The second step is the placement of a bonding agent. This is a very thin type of composite that flows into the enamel irregularities and dentinal tubules. It is then cured (hardened) with a very bright blue curing light. This very thin initial layer is now microscopically locked into the surface of the tooth.

The third step is the addition of a chemically similar composite filling material that then chemically bonds to the first layer. This produces a filling that is actually bonded to the tooth, instead of being simply placed in the tooth like you would pour cement into a post hole.

The two most important features of the composites are a direct result of the fact that composites are bonded to the tooth.

When properly done, composites will last as long as amalgam, they look just like a natural tooth, and they strengthen, rather than weaken the tooth.

For more information on Tooth-Colored Restorations, please call our office at (919) 479-5800.