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

Did you know the terms overbite and overjet are often used interchangeably, but that they are distinct from each other? Our Cornwall dentists explain the difference and how we may be able to correct either issue with 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.


An overbite, also known as a deep bite, occurs when the upper front teeth cover more than one-third of the lower incisors while the jaw is closed. It is characterized by its vertical positioning, which sets it apart from an overjet, which is characterized by horizontal protrusion of the upper teeth.


An overjet, often referred to as "buck teeth," occurs when the upper front teeth extend forward beyond the lower teeth, resulting in a noticeable horizontal overlap.

In a normal bite, the upper front teeth slightly overlap the lower teeth when closing the mouth, but if the space between them is more than 2 millimeters, problems can arise.

While overbites involve a vertical overlap, overjets involve a horizontal protrusion where the upper teeth extend past the lower teeth at an angle. Unlike overjets, overbites feature vertically positioned teeth that are either straight or slant slightly downward, rather than at an 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.

An overbite is characterized by the upper front teeth appearing lower than the adjacent teeth, and it may result in more gum being visible when you smile.

Overbites can be caused by certain habits during childhood, such as prolonged thumb or pacifier sucking, as well as biting nails or chewing on objects like erasers or pens.

Similarly, overjets can also be caused by childhood habits like finger or thumb sucking that continue as adult teeth start to come in. Another common cause is the discrepancy in growth between the upper and lower jawbones, where the upper jawbone (maxilla) grows forward more than the lower jawbone (mandible), causing the lower teeth to end up positioned farther back than ideal for an optimal smile.

Genetic factors can also contribute to the development of overbites or overjets.

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, your risk for 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 poor alignment of teeth. You may also notice challenges with chewing or biting.

Can an overbite or overjet be treated with clear aligners?

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.

Clear aligners are designed to not only move your teeth but also maintain the proper proportions of your gumline. To ensure effective results, it is recommended to wear the clear aligners for approximately 22 hours per day, removing them only for activities like brushing, flossing, eating, and drinking.

Throughout the course of your treatment, your teeth will gradually shift as you progress through a series of aligners. Typically, you will switch to a new set of aligners approximately every two weeks. Depending on your individual treatment plan, you may need to wear up to 26 trays, with each tray being used for a two-week period, totaling around 12 months of treatment.

Prior to initiating the treatment, your dentist will provide you with a preview of how your smile will transform by 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 Cornwall dentists to book a consultation today.

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