The difference between overbite, underbite, crossbite and open bite
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An overbite, underbite, crossbite, and open bite are all types of bite misalignment, but they affect the way your upper and lower teeth meet in different ways. An overbite is when the upper teeth overlap the lower teeth more than normal, an underbite is when the lower teeth sit in front of the upper teeth, a crossbite occurs when some upper teeth bite inside the lower teeth, and an open bite leaves a gap between the upper and lower teeth when your mouth is closed. While some bite differences are mild, others can affect chewing, speech, jaw function, and long-term oral health.
Bite problems, also known as malocclusions, are more common than many people realise. Some cause little more than cosmetic concerns, while others can lead to tooth wear, jaw pain, headaches, or difficulty eating if left untreated. Understanding which type of bite you have is the first step towards finding the most appropriate treatment, whether that’s monitoring the condition or correcting it with orthodontic treatment.
In this guide, we’ll explain the differences between overbites, underbites, crossbites, and open bites, the symptoms each can cause, and the treatment options available. By the end, you’ll have a clearer understanding of how these bite problems differ and when it’s worth speaking to an orthodontist.
An overbite is a vertical misalignment of your teeth. Your upper teeth overlap your lower teeth. This is much more pronounced than it should be. Untreated, an overbite can cause things like jaw pain, gum disease and tooth erosion.
A small overbite is normal. It’s even needed for proper function and health. But anything more than 2-4mm is classed as an overbite.
The teeth don’t necessarily stick out, though. They could be perfectly vertical but just too far forward. If there is some horizontal misalignment, this is called an overjet.
With an overbite, you might end up with the following issues:
Overbites are often genetic, so if your parents had an overbite, you’re more prone to one too. You can also develop an overbite by thumb sucking (or dummy use) past the age of three), teeth grinding (bruxism), excessive nail biting or tongue thrusting, which is when the tongue presses too far forwards.
If an overbite isn’t treated, it can also lead to jaw stiffness, headaches, earaches and neck pain.
An underbite is the opposite of an overbite. The lower teeth extend out in front of your upper teeth. This can be mild or severe. In the most severe of cases, the jaw protrudes outwards to such an extent that it is obvious to others.
As well as the cosmetic issue this causes, an underbite can also cause problems with the jaw and teeth. The most severe underbites cause issues with speech. There may be more wear and tear on the front teeth too. They’re more prone to breakage or chipping. It’s also more difficult to chew food.
Underbites, like overbites, can cause TMD. The jaw may feel locked and click when it moves. This is painful too. Halitosis (bad breath), mouth breath, snoring and sleep apnoea area also associated issues.
An underbite is often genetic but it can be caused by injury like trauma to the jaw and poor subsequent healing. Childhood habits like thumb sucking or dummy use can also cause the jaw to develop differently.
Treatments are available, and these include ordinary orthodontic methods. Sometimes, surgery is required for severe underbites.
With a crossbite, the teeth also don’t sit where they should. But it’s different in that it’s not all of the teeth that are involved. There are two types:
With a crossbite, you can experience:
A crossbite can also be genetic. Sometimes it’s circumstantial—if your milk teeth didn’t fall out or if the adult teeth were delayed, your other teeth might have compensated and developed the crossbite.
Crossbites are treated with braces, retainers, elastics and palate expanders. You can start treating this before the age of 10.
An open bite is when the teeth don’t align or touch when the mouth is shut. It can be caused by thumb sucking or using a dummy, tongue thrusting, temporomandibular joint disorder or a skeletal problem that’s influenced by genetics.
Treatments for open bites include behaviour modification, braces or surgery.
Without treatment, an open bite can affect pronunciation and speech. Many with an open bite have a lisp. It also causes difficulties with biting and chewing. The back teeth can suffer too because they come together more, which causes excessive wear and tear and problems like fractured teeth.
The good news? Most bite issues can be corrected. Most bite problems respond well to orthodontic treatment.
Orthodontic treatments are great for realigning both the teeth and jaw. Braces and Invisalign are two options for dealing with different malocclusions. Whether you have an overbite, underbite, cross bite or open bite, the severity will need to be assessed to get the appropriate next step recommendations.
Braces and retainers have been the go-to for decades. And they’re still highly effective for even complex bite issues. There are the traditional “train track” metal braces, lingual braces (ones that are attached behind the teeth) and even ceramic tooth-coloured options.
Invisalign is a discreet alternative. These are clear and removable aligners. They’re custom-made to guide your teeth into the correct position. Though not suitable for severe bite problems, they’re great for mild to moderate ones. And the best thing? Most people won’t notice you’re wearing them.
Correcting a bite problem isn’t just about aesthetics. It also makes eating, speaking and even breathing easier. It can reduce wear and tear on your teeth and help prevent long-term issues like jaw pain or TMJ disorders.
Not sure which option is right for you?
Book a consultation with our team at Ringway Dental. We’ll talk through your concerns, examine your bite, and put together a treatment plan that works for your smile, lifestyle and budget.
