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

Are you aware that although overbite and overjet are often used synonymously, they are actually two separate dental conditions? Our dental located in Thornhill can clarify the difference and offer potential solutions using clear aligners.

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.


Did you know that an overbite, also known as a deep bite, occurs when the upper front teeth cover one-third of the lower incisors when your jaw is closed? It's important to note that this is different from an overjet, which is a horizontal issue.


An overjet, also known as "buck teeth," occurs when the upper front teeth extend over the lower teeth, resulting in a notable horizontal overlap. Although it's typical for the upper front teeth to sit slightly in front of the lower teeth when closing your mouth, any gap exceeding 2 millimetres can lead to problems. Overbites are vertical, whereas overjets are horizontal and cause the upper teeth to protrude beyond the lower teeth at an angle. However, in an overbite, the teeth remain straight or downward, without any angle.

How are overbite and overjet caused?

The most common causes for overbite is that the lower jaw is somewhat smaller than the upper jaw, resulting in the lower teeth resting behind the upper teeth and moving downwards as wear on your teeth takes place.

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 overbite and overjet create?

In severe overbite cases, the lower teeth may touch the gum tissue behind the upper front teeth, causing damage to both the teeth and gums.  Having an overjet increases the likelihood of teeth damage or fractures. Overjets can vary from barely noticeable to more severe, making it hard to fully close your lips due to misaligned teeth. You may also experience difficulties with chewing or biting.

Can an overbite or overjet be treated with clear aligners?

If your overbite or overjet is due to skeletal issues, clear aligners may not be the recommended option. Instead, it is advised to consult your dentist to explore alternative solutions like surgery.

However, if the overjet or overbite is caused by other factors mentioned earlier, clear aligners could be a viable treatment option. These aligners will gently apply pressure to your teeth, gradually moving them into the correct positions as outlined in a personalized treatment plan provided by your dentist. This will result in a straighter and more symmetrical smile.

The clear aligners also help in maintaining gum proportions while shifting the teeth. You will need to wear the aligners for approximately 22 hours per day, removing them for activities like brushing, flossing, eating, and drinking.

Throughout the treatment, your teeth will gradually shift, and you will switch to a new set of aligners approximately every two weeks. Depending on your specific treatment plan, you may need to wear up to 26 trays, which means changing trays every two weeks for a duration of 12 months.

Prior to starting your treatment, your dentist will be able to show you a preview of how your smile will look at the end of the treatment. To find out if you are a suitable candidate for clear aligners, take the first step by scheduling a consultation with your dentist.

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

Orthodontic Treatment in Thornhill

The team at Thornhill Family Orthodontics is committed to providing a range of orthodontic services tailored to the needs of our patients.  

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