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

While the terms overbites and overjets are often used interchangeably, they are actually different conditions. In this blog, our Lethbridge dentists explain the differences between overbites and overjets and how clear aligners might be able to correct them.

What are overbites and overjets?

Two of the most common orthodontic problems are overjets and overbites. Many people are using these terms interchangeably when they both have key differences between them.

Overbite

An overbite (also known as deep bite) develops when the upper front teeth cover one-third of the lower incisors when your jaw is closed. The vertical characteristic of this condition differentiates from an overjet, which is horizontal.

Overjet

Often referred to as “buck teeth”, overjets occur when the upper front teeth protrude over the bottom teeth, resulting in 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 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).

What causes overbites and overjets?

The most common cause of overbites is when the lower jaw is slightly 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).

People can develop overbites if they had a tongue-thrusting habit or were allowed to suck on an object - most often a thumb or pacifier - for too long as a child. Nail-biting or chewing on items like erasers or pens could also result in this condition.

Like overbites, childhood habits like finger or thumb sucking can cause an overjet if they continue this habit when their adult teeth start to erupt. Another relatively common cause is when the lower jawbone (mandible) can't 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.

Can overbites and overjets cause other dental problems?

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.

If you have an overjet you are at a higher risk for fracturing or damaging your teeth. While some overjets can be hard to notice if they are moderate, more severe cases can make it difficult to fully close your mouth as a result of poor teeth alignment. You might also have trouble biting or chewing.

Can clear aligners treat overbites or overjets?

We don't recommend using clear aligners to treat your overbite or overjet if they are skeletal in nature and you should talk to your dentist about considering other treatment options like surgery.

But, if your overbite or overjet is the result of one of the problems detailed above, clear aligners might be able to help correct your issue. 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.

Prior to starting your treatment, your dentist can show you a preview of how your new smile could look once your treatment is over. Take the first step to schedule a consultation with your dentist to learn if you are a candidate for clear aligners.