Swords Orthodontics
17 Main St, Swords, Co Dublin, Ireland

What's the difference between Overbite and Overjet?

July 25, 2013
|
Posted By: Stephen Murray

At Swords Orthodontics, lots of patients come in and tell us they aren’t happy with their overbite. This still surprises me – I had never heard the word “overbite” until I had been in Dental School for nearly two years.

I can still remember the first time I heard the word used by someone that wasn’t a dentist – it was Wednesday Addams in the Addams Family movie (or maybe the sequel, Addams Family Values). It still isn’t a word I hear too often outside of work, but I know that many of my patients have heard it. Most times though, when someone comes to visit us for the first time at Swords Ortho and talks about their overbite being a problem, they are actually concerned about what dentists call the overjet.

Overbite is the word that does get used in movies and cartoons, because people immediately know it’s something to do with teeth, but the teeth situation that’s obvious in the movie is that the top teeth are too far in front of the lower teeth – which isn’t really an overbite at all.

An overbite is the overlap between the top teeth and bottom teeth at the front. Normally, this is about 3mm, or one-third the height of the lower tooth. If your overbite was large, it would mean there is a big overlap, and your lower teeth bite very deeply behind your top teeth. In extreme cases, you might even be biting the gum behind your top teeth. When the overbite is low, there is less overlap and in some cases there might even be space between the top front teeth and the bottom front teeth – which is a negative overbite, more commonly called an “open bite”.

An overjet is the word that dentists use to describe the amount that the top teeth sit forward of the lower teeth. This is normally about 3mm as well, but it can often be 10mm or more in my patients, and in some cases it can be negative too, where the lower teeth are in front of the top teeth (this would be called a reverse overjet). But overjet doesn’t sound very dental to the general public, so they never use the word in movies!

Orthodontists can fix overjet and overbite problems with a variety of different braces - to find out which is best for you, please get in touch and we can arrange an appointment without charge.

Related Blog Posts
October 7, 2025
Why retainers are important

I had a patient come in this afternoon for an appointment that was marked in the diary as “retainer review”.

When I opened up his notes, it turned out that his orthodontic treatment finished over 3 years ago and we hadn’t seen him in almost 3 years. At that stage we had made him a spare retainer and he never came back to us to have it fitted.

When he came in, I said “so we haven’t seen you in nearly 3 years.”

“Yeah, I know. Sorry about that. Really busy with the leaving cert and that sort of thing,” he said. He explained that his retainer was ...

April 2, 2025
Orthodontics and Mouth Cancer 2025 Part 3...What happened next

After a busy day of orthodontic treatments, I was in the practice one evening doing some treatment planning for the patients that would be coming in later that week and the phone rang with Prof Stassen’s name on the screen.

As he does the jaw surgery and other special procedures for my patients that need them, I’d always take the call when I get it because it usually means something needs to be discussed in detail and I’ll have to make special appointments and the quicker I know what I have to do the quicker I can help my patients. In this case it was “remember ...

March 31, 2025
Orthodontics and Mouth Cancer 2025 Part 2...Our Experience at Swords Ortho

I have blogged about mouth cancer before. We had mouth cancer screening days in the practice, there was a national mouth cancer awareness day.

It’s not one of the more famous ones, there isn’t a national campaign where we wear a ribbon or a flower or have a coffee morning at work for it, but it’s certainly there in the background messing around with people’s lives. Before I was an orthodontist I used to work at the junior levels of various oral surgery departments around Northern Ireland and England and saw many patients receive treatment for it. Those patients were referred to us from one source ...