Upper and lower teeth are aligned in a U-shaped arch with no spaces between the teeth.

The upper arch overlaps the lower arch slightly from the last molar on one side all the way around to the other side.  Notice that in an ideal bite, the upper front teeth overlap the lower front teeth creating a mild “overbite.”  (The correct orthodontic term for “overbite” is overjet.  Overbite actually refers to the vertical, not horizontal overlap of the front teeth.)  Normal overbite and overjet is 2-3 millimeters.  In a normal bite, the upper midline is in line with the lower midline.

For children with baby teeth, you may notice some mild spacing.  This spacing is normal because the adult teeth that will replace the baby teeth are generally larger and require more space to come in straight. 

Notice that when biting from the side, the teeth fit together similarly to the teeth of a zipper.  This provides a stable bite where most teeth occlude (bite) against two other teeth.  Notice the mild overbite where the front teeth occlude.  Many patients and parents come into the office complaining about their overbites, only to be told that their mild overbite is normal.  If there is no overbite, teeth will wear down abnormally so having a mild overbite actually protects the teeth from abnormal wear.  Of course, having a large overbite can be problematic. 

Now that you understand what a set of ideal teeth and bite look like, you will hopefully be able to spot orthodontic problems better.  Follow the links below to see Common Orthodontic Problems in Children or Teens and Adults.