Do you know what I find odd? The concept of how the public views overjet vs overbite. It seems the term overbite gets all the attention. Most people have heard of an overbite, but they don’t have a clue about overjet teeth.
That’s like saying you know what ketchup is, but you’ve never seen yellow mustard before. The point is that overjet and overbite are two completely different orthodontic terms, and most people mistakenly refer to overjet as overbite. That’s a problem because they can both be problematic in different ways.
In this article we will demystify the concept of overjet vs overbite, we’ll talk about normal overjet, and I’ll explain why overjet is one of the most common causes of severe dental issues like temporomandibular joint disorder (TMJ).
What is Overjet?
Okay first things first, let’s answer, what is an overjet?
Quite simply it’s a measurement. It’s the measurement of how far the top front teeth protrude in front of the lower teeth. And its typically measured in millimeters.
If the top front teeth are sticking out far forward that’s a large overjet. If the top front teeth are resting tightly against the lower teeth that is a minimal overjet. An overjet can even be a negative measurement if the lower teeth are in front of the top.
So what is normal, you ask. Normal is about 1-2mm.
The front teeth need to have enough space to close passively—more on that later. But they also ideally should be close enough to allow for a tearing motion, like when biting into corn on the cob or into a slice of pizza. An excessive overjet reduces the ability to bite into food effectively.
Overjet vs Overbite
Okay so now you know what an overjet is. Let’s clarify what an overbite is.
An overbite is also a measurement—except it measures the vertical overlap of the front teeth. If the top teeth are covering more of the lower teeth, that is a large overbite. If the top is covering less of the lower teeth, that is a small overbite. Think of overbite like the shade on a window. If the shade is down all the way that’s analogous to a large overbite and if the shade is up, that’s a small overbite.
A normal overbite is usually in the range of 2-4mm.
Can overjet cause issues with my teeth?
You bet it can. The overjet is a bit like goldilocks and the three bears. Too little or too large are both problematic. Its best when it’s just right.
Some overjets are mild and barely noticeable, there’s a threshold out of the normal range that can be okay. But what I want to talk about is when it is severely small or large. First, let’s talk about what happens with big overjet.
If the overjet is large it means the front teeth are out of harmony with the rest of the face. This can lead to difficulty biting or chewing. But it can also prevent your lips from closing naturally.
A severe overjet can cause cosmetic issues.
You can imagine that if your teeth are propping your lip up, preventing it from closing, that asymmetry might alter the external shape for face.
It can also cause functional issues.
You could also develop speech problems, or frequently the inside of your cheek. And finally, when the overjet is severely large it creates an increased risk of trauma to the front teeth. Because the teeth are more forwardly exposed, there is an increased risk of contacting them if there is a strike to the mouth. These are all casualties of increased overjet.
Can an overjet cause TMJ disorder?
You probably noticed how we talked a lot about what happens when the overjet is large. But you’re probably wondering what happens when the overjet is too small.
When the overjet is severely small, it means that the teeth are contacting very tightly in the front of the mouth. You can imagine that places unnecessary pressure on the front teeth. It predisposes the teeth to chipping or fracturing more easily. And it also places stress on the bone structure of the teeth that can increase the risk of periodontal disease. Sometimes when the overjet is too restrictive the teeth can even wiggle from normal bite force. These are all indications that space is limited.
But that’s just the beginning. What I want you to realize is that its not just about the teeth and gums. It affects the entire head. Allow me to explain.
For a moment I want you to imagine a door closing into a doorframe that is too tight. Guess what happens. To close the door you have to slam it right? Yes, you can close the door, but all that stress wears on the door and also the hinges.
The same thing happens to the jaw when the overjet is tight. You can close your mouth, but ultimately it places stress on the teeth and the hinges of the jaw, the TMJ.
So the take home message is that when an overjet is too limited, the lack of space greatly increases the risk of TMJ disorder.
How do know if overjet is contributing to TMJ Disorder
The best way to know if an overjet is creating a problem is by the symptoms. If you feel like your front teeth are not closing in a comfortable place, that’s an indication that overjet might be a factor. It greatly increases the risk for TMJ disorder.
TMJ disorders may cause mild to severe symptoms, such as:
- pain while chewing
- pain in the ear
- painful clicking or popping when you open or close your mouth
- locking of the jaw
- tension and soreness in the muscles of the face.
What Are the Causes of Overjets?
The overjet can be altered by a variety of factors. Some are genetic just from the development of the jaws.
External factors can cause an overjet to develop. Some of these include:
- Thumb sucking
- Prolonged use of a pacifier or bottle
- Excessive tongue thrusting
- Crowding of teeth
- Wisdom teeth removed too late
- Late growth of adult teeth
How to Fix an Overjet
As we talked about if you have a mild or slight overjet, treatment might not be needed at all. There are some very common options available to improve it. Let’s look at some of them,
Orthodontics like Braces or Invisalign
Dental veneers are a way of changing the alignment and shape of the teeth without orthodontics. A cosmetic dentist will reshape the teeth into a better position and then veneer them so that they are ideal shape in the improved alignment
Dental crowns are a similar process to veneers for improving the overjet. The exception is that a crown is indicated when a tooth has been filled many times before or when a larger portion of the tooth is needed to change. Much like veneers, dental crowns can reshape the teeth into an improved alignment and change the entire positioning of the teeth.
Overjet vs Overbite: Wrapping up
So there you have it. Everything to know about the difference between overjet vs overbite. Now you can understand how the terms are just dental measurements. Everyone has an overbite and an overjet, it’s just people use mistakenly use the terms synonymously.
People also only really talk about them when there is an issue with the measurement. But they are standard measurements that relate to all people, similar to weight and height.