While the terms overbite and overjet are often used interchangeably, they are distinct from each other. In today's post, our Victoria dentists explain the difference and how, in some cases, these conditions can be corrected 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.
Sometimes referred to as a deep bite, 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 distinguishes it from an overjet, which is horizontal.
An overjet is when the upper front teeth protrude over the bottom teeth, creating a significant horizontal overlap. Cases of overjet are commonly referred to as “buck teeth” .
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).
How are overbite and overjet caused?
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. 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 occur due to overbite and overjet?
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 clear aligners be used to treat an overbite or overjet?
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.
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.
Before you start your treatment, your dentist will be able to show you a preview of how your new smile will look by the end of your treatment. Take the first step to schedule a consultation with your dentist to learn if you are a candidate for clear aligners.