Types and Classes of Malocclusion

A normal bite exists when the upper teeth are slightly forward of the lower teeth. If this is not the case, it’s called malocclusion. In short, malocclusion is a poor bite. Malocclusion can be caused by several things such as jaw structure problems in children.

There are several different types of malocclusion which are based on the positioning of the teeth. Additionally, malocclusion is classed based on how the upper and lower teeth fit together.

Types of Malocclusion

Upper Protrusion (Overjet)

Upper protrusion occurs when the upper front teeth are pushed outward creating what is known as “buck teeth.” It can be caused by a small lower jaw, pacifier use, or thumb sucking which can push the front teeth forward sometimes causing the roof of the mouth to change shape. Due to the fact that the teeth are so far forward makes them prone to potential damage.

Spacing and Crowding

Spacing or crowding of the teeth can occur if there is too much or too little room for the teeth. This problem must be corrected as it can potentially prevent the permanent teeth from being able to properly come in or come in at all. While spacing may only be a cosmetic issue, crowded teeth can be difficult to clean causing further problems.

Misplaced Midline

A misplaced midline occurs when the front center line between the upper front teeth doesn’t match up with the center line of the lower front teeth. This is caused when the back bite doesn’t match or fit properly and has the potential to impact jaw growth and proper dental function.

Open Bite

If the molars fit together but the upper and lower front teeth don’t overlap, it’s referred to as an open bite. This is a problem as it creates an opening right into the mouth. This opening can either be on just one side of the mouth or on both sides of the mouth. Apart from being unattractive, an open bite has the potential to cause eating problems, speech problems, and excessive wear of the teeth that don’t meet.

Over bite

When the upper front teeth stretch down too far ending up over the lower front teeth, it’s called an over bite. In the most severe cases, this can cause the lower teeth to bite into the roof of the mouth. Other problems that can occur from an over bite are ulcers and the wearing of the front teeth.

Under bite

An under bite occurs when the lower front teeth are farther forward than the upper front teeth causing the lower front teeth to overlap the upper front teeth. It can cause eating trouble as well as uneven wear of the front teeth.

Cross Bite

If any of the upper teeth fail to fit in with the corresponding lower teeth, this is called a cross bite. Typically, in this situation, the upper teeth sit inside the lower teeth instead of outside as they should. This can cause excessive wear on some teeth or possibly misaligned jaw growth.


When a tooth turns or tips away from its normal position, it is called rotation.


If any teeth grow, or erupt, in the place where another tooth is supposed to, it’s called transposition.

Classes of Malocclusion

Class I

Class I malocclusion occurs when the lower molars are positioned properly but there is spacing or crowding due to there being too much room or too little room for the teeth. In severe cases, this can cause other problems such as cross bites, rotation, or overlapping.

Class II

Class II malocclusion is where the lower molars fit with the upper molars but they are positioned as such that they are toward the throat which causes the chin to draw back.

Class III

Class III malocclusion is where the lower molars are far forward and don’t fit in with the corresponding upper molars. This problem can create a jutting jaw and jutting lower front teeth causing a cross bite of the lower and upper teeth.

If there is a problem with your bite, it’s called malocclusion. This problem should be corrected as it can cause several problems including trouble eating and speaking as well as excessive wear to certain teeth. If you have a poor bite, come seek treatment from Melbourne Orthodontics.