Overbite vs Underbite : Key Differences, Causes, and Treatment Options

There are many aspects of our oral health that we take for granted.

A healthy bite is one of them, as it plays a crucial role in promoting long-term oral health, pain-free chewing, clear speech, and overall structural comfort.

When the alignment of your upper and lower teeth is off, this is referred to as a malocclusion.

The two most common types of malocclusion we’ve observed as a leading Sydney Orthodontist are the overbite and the underbite.

If you have either an overbite or an underbite, do not worry; they are both highly treatable with a variety of options available to correct these issues, no matter whether you’re a child or an adult.

At Fox Orthodontics, we have been helping patients achieve their dream smile for more than 40 years, and proudly provide specialist orthodontic treatment to the residents of Baulkham Hills, Norwest, Hills District, Castle Hill, Parramatta, Kellyville, Blacktown, Orange and Bathurst.

In this article, we will break down the fundamental differences between an overbite and an underbite, what can cause this phenomenon to occur, and the different treatment options available for you.

What Does A Healthy Jaw Look Like?

So what does an ideal bite look like? Well, the upper teeth should overlap the lower teeth vertically, but only by about 1-3mm.

Each upper tooth should fit neatly between two lower teeth, essentially acting as gears. Regarding your back teeth, the molars should be touching evenly on both sides.

This balance means that chewing pressure is spread evenly throughout the mouth and not concentrated in one spot, which can create a variety of issues.

What should this feel like? Well, essentially like a well-oiled machine.

Overall, your structure should be comfortable and stable, with no strain in the jaw joints or muscles, and balanced chewing all around.

So what does it look like when it’s off?

Let’s break down the underbite and overbite.

What Is An Overbite?

An overbite is the more commonly seen issue between the two.

An overbite is when a patient’s upper front teeth protrude over the lower front teeth.

While a small gap is expected, when the top front teeth cover too much of the bottom teeth, it becomes an issue.

Minor Overbite :

A minor overbite will generally only affect appearance and involve the front teeth being partly hidden when you bite down.

It usually isn’t enough to cause problems, but the bite should still feel reasonably comfortable and stable.

Major Overbite :

A severe overbite can be dangerous, with some patients experiencing their lower teeth hitting the roof of their mouth or the gums behind the top teeth when they bite. It can cause significant discomfort in the jaw, difficulty chewing, and uneven wear on the lower teeth.

What Happens If An Overbite Is Left Untreated?

It really depends on the severity of the overbite, but let’s say it’s on the more severe end of the spectrum.

This can lead to several issues over time.

• Tooth wear and damage : The lower front teeth can wear down faster, with chipping or cracking commonly observed, along with enamel erosion from uneven pressure.
• Gum and palate irritation : In severe cases where the lower teeth consistently hit the roof of the mouth or gums, the patient will experience regular soreness and potential tissue damage.
• Jaw strain and dysfunction : An overbite causes your jaw muscles to work harder to close properly. This, over time, can cause jaw pain, clicking, headaches, or facial tension.
• Bite instability and chewing inefficiency : Over time, your teeth may slowly shift, potentially worsening the bite. It also causes less balanced chewing, which creates overall fatigue and discomfort when eating tougher/chewier foods.

What Is An Underbite?

An underbite is when a patient’s lower teeth sit in front of the upper teeth when they bite down.

This creates a reversed bite, with the bottom front teeth ahead of the top front teeth.

In most cases, the jaw or chin may appear more prominent. Both functional and aesthetic problems can arise if an underbite is left untreated.

Minor Underbite :

A minor underbite will have the lower front teeth sitting just slightly in front of the upper front teeth.

On the whole, your face and jaw will still look fairly balanced, with often no major problems to worry about.

Treatment is not always required, and instead, it may just be monitored by a dentist or orthodontist.

Major Underbite :

A major underbite will involve the front teeth clearly overlapping the upper front teeth, the jaw will sit prominently forward, and the upper teeth may sit consistently behind the lower teeth.

Those with a major underbite may experience common jaw strain, clicking, and fatigue.

Over time, if left untreated, patients will be at a higher risk of tooth wear, gum damage, TMJ problems, chewing inefficiency and their bite worsening over time.

What Happens If An Underbite Is Left Untreated?

It really comes down to how severe the underbite is, but let’s say it’s on the more severe end of the spectrum.

This can result in several issues over time.

• Gum problems : As your teeth may bite into gums, it can increase the risk of recession, irritation and overall discomfort.
• Jaw strain : With an underbite, your jaw muscles and joints have to work harder to compensate. This can result in jaw pain, clicking, headaches, neck and face tension.
• Chewing Difficulty : Biting into certain foods, such as apples and sandwiches, can be uncomfortable and awkward. Many patients often become fatigued from chewing and experience a feeling of unevenness.
• Bite Progression : Over time, your teeth may shift with the underbite slowly worsening, especially if you are someone who frequently grinds or clenches their teeth.

What Is The Difference Between An Overbite And Underbite?

If you are still unsure how to properly distinguish between an overbite and an underbite, the Fox Orthodontics team has prepared the table below to clearly break down the orthodontic phenomena.

What Causes Overbites and Underbites?

Both overbites and underbites have similar causes, and understanding these can help you better recognise the causes of your own oral predicament.

• Genetics : Plays a big role in both underbites and overbites, with many patients inheriting a specific jaw structure. It could be a small lower jaw or a smaller upper jaw.
• Childhood Habits : Many habits we develop in early childhood, such as thumb-sucking, extended pacifier use, or pushing the tongue against teeth, influence the development of the jaw.
• Jaw Development : If your lower jaw grows more than the upper jaw, or if your upper jaw fails to develop properly. If you also have overdeveloped jaw muscles, this can sometimes create a serious overbite.
• Past Trauma : If you have suffered a severe injury in the past to your face or jaw, this can cause misalignment.
• Teeth Grinding : Frequent teeth grinding (bruxism) can wear down teeth over time, which can exacerbate a pre-existing overbite.

How Are Overbites And Underbites Diagnosed?

Overbites and underbites are usually picked up by a dentist during a check-up.

If they suspect that this may be the cause, they will usually take X-ray imaging to further understand how your teeth currently align.

If they believe it to be a serious issue, they will refer you to an orthodontist.

An orthodontist will use further examinations and imaging to determine where the root of the issue is and how best to proceed regarding correcting it.

What Are The Treatment Options For Overbites And Underbites?

While anyone with an overbite or underbite can receive treatment to correct the issue, the type of treatment that is used will vary depending on whether the patient is a child or an adult.

Treatment For Children

As a result of children’s jaws still developing, their teeth are more malleable, with orthodontic treatments able to easily guide growth.

Some of the most common treatments used in Australia for an underbite and overbite include:

• Braces/Clear Aligners : Are an effective orthodontic tool to move all teeth into proper alignment. They work to not only straighten teeth but also correct a bite.
• Tooth Removal : In certain cases, an orthodontist may see it as necessary to remove a baby tooth to make space for adult teeth.
• Retainers : Often used after braces treatment to keep teeth properly aligned.
• Palatal Expanders : This orthodontic tool widens the roof of the mouth to reduce an overall underbite.
• Orthodontic Headgear : Otherwise known as a facemask, it encourages the upper jaw to grow forward.
• Habit Breaking : Especially for young children, stopping thumb sucking habits or pacifier use can sometimes halt the development of an overbite or underbite.

Treatment For Adults

With adults’ jaws being fully developed, some skeletal corrections are often required during surgery.

No matter your age, you can benefit from orthodontic treatment. For some people, this won’t be enough, and they will need surgery to address the issue.

• Braces or Clear Aligners : Are still appropriate for adult teeth and have proven their ability to reposition teeth to their desired position.
• Jaw Surgery : If an individual has a moderate to severe underbite, then jaw surgery (orthognathic surgery) will often be required.
• Tooth Reshaping/Extractions : Is used to create space for proper alignment and give the remaining teeth extra room.
• Tooth Adjustments or Dental Crowns : May be used to improve an individual’s bite.

Can An Overbite and Underbite Be Prevented?

So, can you actually prevent an overbite and underbite from occurring?

Well, yes and no. If you have a genetic predisposition to either an overbite or an underbite, or are born with either, then that’s not something you can account for.

However, you can do a certain number of things during the early stages of life to set yourself up for success.

The table below breaks down several ways to help prevent an overbite or underbite from developing.

When Should You See An Orthodontist For An Overbite Or Underbite?

The Australian Society of Orthodontists recommends a child get their first orthodontic assessment between the ages of 7 and 10.

Early detection of a potential overbite or underbite allows dental professionals to treat issues while the child is still growing, which is when treatment is considered most effective.

Signs to look out for that may indicate you should see an orthodontist as both a child and an adult include :

• The upper teeth cover too much of the lower teeth, which indicates an overbite
• The lower teeth sticking out past the upper teeth, which indicates an underbite
• Regular jaw clicking, popping or general pain
• Discomfort or difficulty when chewing, biting, or speaking clearly
• Teeth crowding, shifting, or wearing unevenly
• Jaw pain, headaches, or TMJ issues
• Worn, chipped or uneven teeth
• Desire to improve your overall appearance, smile, or bite alignment

Why Choose Fox Orthodontics?

If you are beginning to suspect that you or your child has an overbite or underbite, it’s important to target the issue as early as possible.

The passionate team at Fox Orthodontics are experts at treating both overbites and underbites.

We are a family-run practice that boasts more than 40 years of clinical experience serving the locals of the Northwest & Hills District.

Get in touch with our team today by clicking here or calling us on 02 7804 4113 and get your smile back on track.