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

The terms overbite and overjet are often used interchangeably, but they do have their differences. Today, our Yarmouth dentists share how overbite and overjet differ, and discuss a possible treatment option in clear aligners.

Overbite & Overjet

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


An overbite occurs 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 is the key difference from an overjet, which is horizontal.


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 greater than 2 millimetres will cause issues.

Overbites are vertical, while overjets are horizontal and cause the upper teeth to protrude past the bottom teeth at an angle. But with an overbite, the teeth remain downward or straight (not on an angle).

Causes of Overbite & Overjet 

The most common cause of an 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.

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).

Genetic factors can also cause overbite or overjet.

Problems Overbite & Overjet Can Lead To

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

With an overjet, your risk of damaging your teeth or fracturing them increases. Some overjets are barely noticeable as they are moderate, while others are more severe and can make it difficult to close your lips completely due to the poor alignment of teeth. You may also notice challenges with chewing or biting.

Treating Overbite or Overjet With Clear Aligners

If the overbite or overjet is skeletal, we would suggest speaking to your dentist to explore other options, such as surgery, as opposed to clear aligners.

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 dentist will be able to show you a preview of how your new smile will look by the end of your treatment before you even begin. The first step is to schedule a consultation with your dentist to see if you are an eligible candidate for clear aligners.

Are you wondering if clear aligners could help fix your overbite or overjet? Contact our Yarmouth dentists to book a consultation.

Helping Achieve Your Oral Health Goals

At SouthWest Dental, we are dedicated to helping you achieve optimal oral health with a range of dental services that can be tailored to your needs.

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