Illustration copyright 2000 by Nucleus Communications, Inc. All rights reserved. http://www.nucleusinc.com
Occlusion is a perfect fit (alignment) of the teeth and jaws. This is also known as a "proper bite." Naturally perfect bites are rare. Most people have some form of malocclusion ("poor bite"). Orthodontists use braces and other tools to move teeth into alignment to achieve occlusion.
WebMD Medical Reference from Healthwise