While traditional dentistry focuses on oral hygiene and preventing, diagnosing and treating oral disease, cosmetic dentistry focuses on improving the appearance of a person's teeth, mouth and smile. In other words restorative, general and/or family dental practices address dental problems that require necessary treatment, whereas cosmetic dentistry provides elective – or desired – treatments or services.

Cosmetic dentistry may also provide restorative benefits. For example, dental fillings are a common procedure used to treat decayed teeth. Previously, most dental fillings were composed primarily of gold, amalgam and other materials that left visible dark spots on the teeth.

Today, dental fillings may fall into the category of cosmetic dentistry, because you can select fillings made of porcelain or composite materials that closely match the color of your teeth, thus maintaining the natural appearance of your teeth and smile. Many people may choose to have their older fillings replaced with newer, tooth-colored fillings to enhance their oral appearance.

Most of us start out with sparkling white teeth, thanks to their porcelain-like enamel surface. Composed of microscopic crystalline rods, tooth enamel is designed to protect the teeth from the effects of chewing, gnashing, trauma and acid attacks caused by sugar. But over the years enamel is worn down, becoming more transparent and permitting the yellow color of dentin – the tooth's core material – to show through.

During routine chewing, dentin remains intact while millions of micro-cracks occur in the enamel. It is these cracks, as well as the spaces between the crystalline enamel rods, that gradually fill up with stains and debris. As a result, the teeth eventually develop a dull, lackluster appearance.

Teeth whitening removes the stains and debris, leaving the enamel cracks open and exposed. Some of the cracks are quickly re-mineralized by saliva, while others are filled up again with organic debris.