Last updated: March 2026
Your dentist said your child has an overbite. Or was it an overjet? Most parents leave that appointment not entirely sure, because the two terms sound almost identical and even some dentists use them interchangeably. They are not the same thing.
Both affect how the teeth fit together. Both can cause problems if left untreated. And both show up on the same face in a way that makes them easy to confuse. But the direction of the problem is completely different, and that changes what treatment looks like.
What Is an Overbite?
An overbite is a vertical problem. It refers to how much the upper front teeth overlap the lower front teeth when the mouth is closed. A small amount of overlap is normal. Orthodontic sources typically describe normal overbite as roughly 1 to 3mm of vertical overlap, or about 20 to 40 percent coverage of the lower incisors. When the upper teeth cover significantly more than that, it is classified as an excessive overbite, sometimes called a deep bite.
In severe cases, the lower front teeth are barely visible when the mouth is closed. Some patients bite so deeply that their lower teeth contact the roof of the mouth behind the upper teeth.
Genetics plays the largest role in overbite development. Jaw size, arch shape, and childhood habits like prolonged thumb-sucking or pacifier use can all contribute. Research links extended non-nutritive sucking to increased overbite, increased overjet, and posterior crossbite, with risk tied closely to duration and frequency. Dr. Patel sees overbites in patients of all ages, but evaluating them early, especially in kids between 7 and 10, makes a meaningful difference in what treatment options are available.
What Is an Overjet?
An overjet is a horizontal problem. It refers to how far the upper front teeth protrude forward beyond the lower front teeth, measured straight back from lower to upper. Normal overjet is roughly 1 to 3mm. When that distance is larger, the upper teeth stick out noticeably. That is where the term “buck teeth” comes from.
Unlike an overbite, which is measured vertically, overjet is about front-to-back distance. If you look at someone’s profile and their upper teeth sit well in front of their lower teeth, that’s overjet.
Common causes include upper jaw protrusion, a lower jaw that sits further back than ideal, genetics, and habits like tongue thrusting. Research shows tongue thrust swallowing is associated with significantly increased overjet compared to controls, and prolonged bottle feeding can contribute by affecting tongue posture and orofacial development. Overjet also carries a documented injury risk: studies show children with overjet of 6mm or more face roughly three times the risk of traumatic dental injury to their front teeth compared to children with smaller overjets. That’s one reason Dr. Patel pays close attention to overjet measurements in younger patients.
3 Ways to Tell the Difference Between Overjet and Overbite
This is the part nobody explains clearly. Here are three ways to figure out which one you are looking at, with or without a mirror.
1. Look at it from the front vs. the side
Overbite is most visible from the front. When someone closes their mouth, look at how much of the lower front teeth disappear behind the upper front teeth. If more than about a third to a half of the lower teeth are hidden, that is a sign of excessive overbite.
Overjet is most visible from the side. Look at the profile. If the upper teeth sit noticeably further forward than the lower teeth, that is overjet. A straight-on photo will not show it clearly.
2. Think about the direction of the gap
Overbite: the gap between upper and lower teeth is up-down. One set covers the other.
Overjet: the gap between upper and lower teeth is front-to-back. One set is in front of the other.
If you are standing above someone looking down, you would see the upper teeth sitting over the lower. That is overbite.
If you are standing beside someone looking at their profile, you would see the upper teeth sticking out in front of the lower. That is overjet.
3. Use the comparison table
| Factor | Overbite | Overjet |
|---|---|---|
| Direction | Vertical | Horizontal |
| Normal range | 1 to 3mm overlap (20 to 40% coverage) | 1 to 3mm protrusion |
| Visual sign | Lower teeth hidden when viewed from front | Upper teeth protrude when viewed from side |
| Common term | Deep bite | Buck teeth |
| Main causes | Jaw size, genetics, prolonged thumb/pacifier use | Jaw position, genetics, tongue thrusting, bottle feeding |
| Treatment | Braces, aligners, bite plates, functional appliances | Braces, aligners, rubber bands, headgear, functional appliances |
Can You Have Both an Overbite and an Overjet?
Yes, and it is more common than most people realize. Many of the patients Dr. Patel evaluates have a measurable degree of both.
The two conditions affect different planes of the bite but often develop from the same underlying causes: jaw size, jaw position, and genetics. Someone with a lower jaw that sits further back than ideal may have upper teeth that both protrude forward (overjet) and overlap more deeply (overbite) at the same time.
Having both does not automatically mean treatment is more complex, but it does mean the treatment plan needs to address the horizontal and vertical components together. That is something Dr. Patel assesses at the initial evaluation, taking measurements in both dimensions before recommending a course of treatment.
Which One Is Worse, and Does It Need Treatment?
Neither is automatically worse. Severity matters more than type.
A mild overbite of 3 to 4mm with no functional symptoms may need monitoring but not immediate treatment. A severe overbite where the lower teeth are contacting soft tissue is a functional problem that needs to be addressed. The same logic applies to overjet: a small amount of protrusion that does not affect chewing or speech is different from an overjet large enough to put the front teeth at meaningful risk of injury.
What Dr. Patel looks for beyond measurements: Is the bite causing wear on teeth that should not be wearing? Is there jaw discomfort? Is the overjet making the front teeth vulnerable to trauma, especially in a child who plays sports? Are speech patterns being affected? Those functional questions matter as much as the millimeter count.
For kids, timing is worth paying attention to. The American Association of Orthodontists recommends that every child have an orthodontic evaluation by age 7. That is not because most 7-year-olds need treatment. By around age 7, enough permanent teeth have erupted to assess molar relationships, jaw growth patterns, and bite problems like overbite and overjet. Catching certain issues during active jaw growth opens up treatment options that are not available once growth is complete.
For adults, both overbite and overjet are treatable at any age. The approach may differ, but neither condition is off the table once the jaw has stopped growing.
How Overjet and Overbite Are Treated
Both conditions are routinely corrected with braces or clear aligners. The specifics depend on severity and what is causing the problem.
For overbite correction, treatment typically involves braces with elastics positioned to open the bite and bring the teeth into better vertical alignment. In growing patients, functional appliances are commonly used during Phase I treatment to take advantage of active jaw development. Research shows functional appliances successfully reduce overjet and overbite to normal limits and are particularly effective when facial growth is still active. In adults with severe overbite, orthognathic surgery is occasionally needed, though most cases do not require it.
For overjet correction, the approach in milder cases involves braces or aligners with rubber bands to bring the upper teeth back and encourage the lower jaw forward. More significant overjet, especially where jaw position is the main driver, may involve headgear in younger patients to restrict maxillary growth and distalize upper molars, alongside other orthodontic work. In adults, a combination of orthodontic treatment and surgical correction handles the most severe cases.
When both are present, treatment addresses them together. Dr. Patel plans the sequence carefully, since correcting one affects the other, and order matters for efficiency and outcome.
To see what bite correction results actually look like, take a look at what overbite correction looks like before and after. If you are thinking about treatment costs, what braces cost in NC covers what Cary families typically pay.
Have questions about your child’s bite? Dr. Patel is happy to take a look, no commitment, no runaround. Book a free consultation at Tooth By Tooth and get a clear picture from the doctor who will actually do the work.
Frequently Asked Questions
What is the difference between overjet and overbite?
An overbite is a vertical problem where the upper front teeth overlap too far down over the lower front teeth. An overjet is a horizontal problem where the upper front teeth protrude too far forward in front of the lower front teeth. Both affect how the teeth fit together, but in different directions.
Can you have an overbite and overjet at the same time?
Yes. Many patients have a measurable degree of both. They often develop from the same root causes, including jaw position and genetics, and are typically addressed together within a single course of orthodontic treatment.
Which is worse, an overbite or an overjet?
Neither is automatically more serious. Severity determines how much treatment is needed. Functional problems like tooth wear, jaw discomfort, or injury risk matter as much as the measurement itself. Both are treatable at any age.
At what age should an overbite or overjet be evaluated?
The American Association of Orthodontists recommends that children have their first orthodontic evaluation by age 7. By that age, enough permanent teeth have erupted to assess jaw relationships and bite problems. Most children will not need treatment at that age, but some issues are significantly easier to address during active jaw growth.
Can braces fix both overjet and overbite?
Yes. Braces are the most common treatment for both conditions and can address the vertical and horizontal components of the bite at the same time. Clear aligners work for many cases as well. Severe jaw-position problems occasionally require additional intervention, but most overjet and overbite cases are handled with orthodontic treatment alone.
About the Author
Dr. Nishant Patel, DDS, MS — Orthodontist & Founder, Tooth By Tooth Orthodontics
Dr. Patel earned his DDS from the University of Illinois at Chicago, graduating at the top of his class, and his MS with orthodontic certificate from the University of Minnesota. His research has been published in the American Journal of Orthodontics and Dentofacial Orthopedics. After eight years practicing in the Chicago suburbs, he founded Tooth By Tooth Orthodontics in Cary, NC. He evaluates overbites and overjets in patients of all ages and sees every patient personally.
