What's the difference between Overbite and Overjet?

July 25, 2013
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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.

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