INTRODUCTION
There's no denying the importance of an attractive smile. According to a survey conducted recently by the American Academy of Cosmetic Dentistry, 9 out of 10 Americans think that having a good-looking smile is an important asset. 88% of those surveyed said that they were likely to remember someone with an engaging smile. On the other hand, 75% said they felt an unflattering smile could hurt a person's career prospects.

Although we'd all like to have a perfect smile, the fact is, not all of us do. With the advent of composite dental resin, that "smile factor" can become our greatest asset.

What Is A "Composite"?
Up until the 1960's, the only kind of fillings available to combat cavities were amalgam (silver) or gold restorations. These metal fillings were effective, but very conspicuous. Once the amalgams had been in the tooth for a while, they tended to blacken in color. This often looked unsightly and embarrassing to the person wearing the fillings.

In the 1970's, "white fillings" came into common use. These "tooth-colored fillings" were made of a plastic dental resin filled with microscopic filler particles and were called composites. When dental composites were first introduced, they could only be used in the front teeth, because they weren't strong enough to withstand the chewing pressure of the back teeth (in excess of 40,000 pounds per square inch).

The composites of today have been vastly improved over the ones developed nearly forty years ago. They are strong, durable, and attractive. Last year, in 1999, the American Dental Association gave white fillings its seal of approval and now many insurance plans cover their use. [See Tooth-Colored Fillings: Costs and Insurance for more information].

What Causes Tooth Decay?
About 170 million times per year, Americans have tooth decay removed, and a filling replaces the lost tooth structure. There are several things which contribute to tooth decay, including:

• Bacteria invade the tooth.
  
• Food particles remaining on the tooth and along with the bacteria turn into a sticky substance called "plaque."
  
• Carbohydrate foods, which contain sugars, feed the bacteria in the plaque.
  
• If not quickly brushed away, the bacteria in the plaque produce acids that begin to dissolve the tooth. This is called tooth decay.
  
• If left untreated, the bacteria colonies continue to grow and destroy the tooth, until the decay reaches the dentin.
  
• Once the tooth decay reaches into the dentin, it can destroy its way rapidly towards the "pulp" of the tooth, which is the innermost part. The pulp contains living cells, blood vessels and nerves. This makes the tooth start hurting! If not treated at this stage, the tooth will likely die.

• In the grooves of teeth, especially in the back (molars) [see sealants]
  
• In between teeth (a good reason to floss)
  
• On the root surfaces of older patients, whose gums have receded.