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Overbite vs. Overjet: How Can You Tell the Difference - and Can Clear Aligners Help?

Did you know that while the terms overbite and overjet are frequently used interchangeably, they are distinct? Our Toronto dentists explain the distinction and how clear aligners may be used to correct either issue.

What are overbites and overjets?

Overbites and overjets are two of the most common orthodontic issues. Though the terms are often used interchangeably, there are distinct differences between these two conditions.


An overbite, also known as a deep bite, occurs when the upper front teeth cover one-third of the lower incisors when the jaw is closed. This issue is vertical, as opposed to an overjet, which is horizontal.


Commonly called “buck teeth” an overjet is when the upper front teeth protrude over the bottom teeth, creating a significant horizontal overlap.

While it’s normal for upper front teeth to rest slightly in front of your lower teeth when closing your mouth, any space of more than 2 millimetres usually causes issues.

Overbites are vertical, whereas overjets are horizontal, causing the upper teeth to protrude at an angle past the lower teeth. However, with an overbite, the teeth remain straight or downward (not on an angle).

How are overbite and overjet caused?

The most common cause of overbite is that the lower jaw is slightly smaller than the upper jaw, causing the lower teeth to rest behind the upper teeth and gradually move downward as your teeth wear.

Your upper teeth will typically show more gum, and your upper front teeth will sit slightly lower than the teeth adjacent to them (upper side teeth, or canines).

Overbites can occur if a patient has a tongue-thrusting habit or was allowed to suck on an object for an extended period as a child - typically a pacifier or thumb. This issue can also be caused by biting the nails or chewing on objects such as erasers or pens.

As with overbites, persistent childhood habits such as finger or thumb sucking can result in overjet when adult teeth begin to emerge. Another common cause is that the lower jawbone (mandible) does not develop at the same rate as the upper jawbone's forward growth (maxillary). Due to this growing disparity, the bottom jawbone (and thus the teeth) end up being positioned behind where they should be for an ideal smile.

Genetic factors can also cause overbite or overjet.

What dental problems can overbite and overjet create?

In extreme cases of overbite, the lower teeth may touch the gum tissue behind the upper front teeth, creating wear on the teeth and gum tissue.

With an overjet, the risk of damaging or fracturing your teeth increases. While some overjets are barely noticeable due to their mild severity, others are more severe and can make it difficult to completely close your lips due to improper tooth alignment. You may also experience difficulty chewing or biting.

Can an overbite or overjet be treated with clear aligners?

If the overbite or overjet is skeletal, 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 above-mentioned problems, we may be able to treat it with clear aligners. The aligners will gradually apply pressure to your teeth, repositioning them in the manner prescribed by your dentist in a customized treatment plan. This will result in a more symmetrical, straighter smile.

Additionally, the clear aligners move your gums, which helps maintain proper proportions. Each day, you must wear your clear aligners for approximately 22 hours, removing them only to brush, floss, eat, and drink.

With the aligners, your teeth will gradually shift, and you'll switch to a new set approximately every two weeks. Your customized treatment plan may require you to wear up to 26 trays, which equates to one tray every two weeks for 12 months.

Before beginning treatment, your dentist should be able to show you a preview of how your new smile will appear after the procedure. Schedule an appointment with your dentist to determine if you are a candidate for clear aligners.

Would you like to find out whether clear aligners would help fix your overbite or overjet? Contact our Toronto dentists to book a consultation today.

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