Underbites, Overbites and Crossbites – What’s the Difference?

The first thing people usually think about when considering orthodontic treatment is straight teeth. However, teeth can be straight without proper alignment of the bite, which can affect overall health.


When the teeth and jaws are out of alignment, breathing, speech, and even the appearance of the face can be affected. This is called “malocclusion”, or more commonly a “bad bite”, and can result in crooked teeth, uneven tooth wear, and protrusion of the teeth over time.

Having naturally straight teeth is actually pretty rare!  Most people have a malocclusion to some degree, but it is generally not severe enough to need any intervention. Malocclusions that are more serious require orthodontic treatment to resolve the problem.

Underbites, overbites and crossbites are all types of malocclusions, but what distinguishes one from another? Before we get into malocclusions, what does a normal bite look like?

Normal Bite (Class I Occlusion)

In a normal or “Class I” bite, the upper teeth are on the outside of the lower teeth, the lower canines are slightly in front of the upper canines, and the lower molar is slightly in front of the upper molar. The teeth should mesh together, with the upper and lower front teeth overlapping slightly.

Overbite (Class II Malocclusion)

Now let’s look at an overbite:

The common term of “overbite” is a bit of a misnomer. The horizontal distance between the upper and lower front teeth is officially known as “overjet”. Overbite actually refers to the vertical overlap of the upper and lower front teeth. So, what is commonly known as an “overbite”, is usually “increased overjet”, or a “Class II” bite. In a Class II bite, the upper front teeth are significantly ahead of the lower front teeth. Overbites can lead to gum issues or irritation and even wear on the lower teeth, and are known to cause painful jaw and joint problems. Overbites can usually be traced to genetics, bad oral habits, or overdevelopment of the bone that supports the teeth.

Underbite (Class III Malocclusion)

Now let’s look at an underbite:

Underbites,  which are technically known as a “Class III” bite, occur when the lower teeth protrude in front of the upper front teeth, are caused by undergrowth of the upper jaw, overgrowth of the lower jaw, or both. Underbites can also be caused by missing upper teeth, which can prevent the normal function of front teeth (molars). This in turn leads to tooth wear and pain in your joints and jaw.


Some bite problems actually have to do with a discrepancy in width between the upper and lower jaws, which is called a crossbite. Let’s look at one:

• Crossbites, which can involve a single tooth or a group of teeth, occur when your upper and lower jaws are both misaligned, and usually causes one or more upper teeth to bite on the inside of the lower teeth. Crossbites can happen on both the front and/or the sides of the mouth, and are known to cause wear of the teeth, gum disease and bone loss.

Fortunately, we are able to treat all of these bite problems, and most of them are most easily corrected before all of the adult teeth have erupted. If you suspect you or your child has a bite misalignment, we encourage you to come in for a complimentary consultation. By starting early, you can make sure you or your child avoid years of pain and self-consciousness.

Call 661-829-7970 or for your complimentary initial exam and get started today.