Overbite vs. Overjet: How Can You Tell the Difference?

The terms overbite and overjet are usually used interchangeably, but they are both different. Here, our Edmonton dentists discuss the differences between overjet and overbite and how each condition can be corrected with clear aligners.

What are overbites and overjets?

Overbites and overjets are among the most common orthodontic conditions. But, the two terms are frequently used interchangeably, when there are distinct differences between them.


An overbite can also be called "a deep bite" and it develops when one-third of the lower incisors are covered by the upper front teeth while your jaw is in a closed position. The vertical nature of this issue distinguishes it from an overjet, which is horizontal.


This condition is also known as “buck teeth”. An overjet happens when the front upper teeth protrude over the bottom teeth, causing a significant horizontal overlap.

While it’s normal for the upper front teeth to rest slightly in front of your lower teeth when closing your mouth, any space of more than 2 millimetres can lead to problems.

Overbites are vertical, while overjets are horizontal and make the upper teeth protrude beyond the bottom teeth at an angle. Although, with an overbite, the teeth remain downward or straight (not on an angle).

What causes an overbite or overjet?

The most common cause of an overbite is when the lower jaw is somewhat smaller than the upper jaw, making the lower teeth rest behind the upper teeth and move downwards as wear on your teeth occurs.

More gum will tend to show on your upper teeth, and your upper front teeth sit slightly lower than the teeth beside them (upper side teeth, or canines).

Overbites can occur if a patient had a tongue-thrusting habit or was permitted to suck on an object - usually a pacifier or thumb - for too long as a child. Biting the nails or chewing on objects such as erasers or pens can also cause this issue.

Similar to overbites, childhood habits such as finger or thumb sucking can cause overjet if they persist when adult teeth begin to emerge. Another common cause is that the lower jawbone (mandible) fails to keep up with the development of the forward growth of the upper jawbone (maxillary). This disparity in growth results in the bottom jawbone (and consequently the teeth), ending up situated behind where they should be for an ideal smile.

Genetic factors can also cause overbite or overjet.

What dental problems can be caused by overbite and overjet?

In extreme overbite situations, the lower teeth could touch the gum tissue behind the upper front teeth, causing wear on the teeth and gum tissue.

With an overjet, you have an increased risk of damaging or fracturing your teeth. Some overjets are barely noticeable when they are moderate, while other more severe cases can make it hard for you to completely close your lips because of the poor alignment of teeth. You could also have a hard time chewing or biting.

Can clear aligners help treat an overbite or overjet?

If the overbite or overjet is skeletal in nature, we would not recommend clear aligners and instead suggest speaking to your dentist to explore other options, such as surgery.

However, if the overjet or overbite is caused by one of the issues listed above, we may be able to treat the problem with clear aligners. The aligners will apply gradual pressure to your teeth to move them into corrected positions as prescribed by your dentist in a custom treatment plan. This will leave you with a straighter, more symmetrical smile.

The clear aligners also move your gum at the same time, keeping proportions in check. You will need to wear your clear aligners for about 22 hours each day, removing them to brush, floss, eat and drink.

Your teeth will progressively shift with the aligners, and you’ll switch to a new set approximately every two weeks. Your custom treatment plan could involve wearing as many as 26 trays, which equates to one tray every two weeks for 12 months.

Before you start your treatment, your dentist will be able to show you a preview of how your new smile will look by the end of your treatment. Take the first step to schedule a consultation with your dentist to learn if you are a candidate for clear aligners.

Contact our Edmonton dentists today and learn if clear aligners can help correct your overjet or overbite.

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