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Your smile is one of the first things people notice, and when your bite isn’t aligned, it can affect more than just appearance. An underbite, where the lower teeth sit in front of the upper teeth, is more common than you might think. While some people only experience a mild case that barely affects daily life, others face challenges with chewing, speech, and long-term dental health.
The good news? Modern orthodontics has made underbite treatment more effective, comfortable, and accessible than ever. From early interventions for children to advanced clear aligners and surgical solutions for adults, there is now a wide range of options to suit different needs. In this guide, we’ll walk you through the science behind underbites, including what causes them, how they are diagnosed, the different types, and the treatment paths available. By the end, you are going to understand not just the “what” and “why” of underbites, but also how today’s technology, including Zenyum’s innovative approach to treat different kinds of teeth conditions is transforming the way we treat them, and it's often without the need for invasive surgery. Let’s dive in!
An underbite, medically known as a Class III malocclusion, is a dental condition where your lower teeth protrude further forward than your upper teeth, causing an unusual bite alignment. While a slight overlap of the lower jaw is normal, a pronounced underbite can affect not just your smile, but also your speech, chewing efficiency, and even overall oral health. In orthodontics, this is commonly referred to as a "reverse overbite" or "prognathism".
Understanding underbites starts with distinguishing between two primary categories: skeletal underbites and dental underbites.
When orthodontists talk about jaw misalignment, they are referring to the anatomical relationship between the upper jaw (maxilla) and lower jaw (mandible). Normally, your upper teeth slightly overlap your lower teeth, providing optimal function and aesthetics. In the case of an underbite, the opposite occurs: the lower teeth jut out ahead of the upper teeth. This jaw misalignment can put extra stress on your teeth, gums, and jaw joints (temporomandibular joints or TMJ), potentially leading to issues like tooth wear, discomfort, and TMJ disorders.
Knowing the specific type of underbite, whether skeletal or dental, is important for effective treatment planning. Skeletal underbites, due to their bone structure origin, may sometimes require surgical intervention, especially in adults. Dental underbites, however, can often be corrected with orthodontic treatments like braces or clear aligners. The good news? Modern orthodontics, including technologies such as Zenyum's advanced clear aligners and AI-driven treatment plans, are making it easier than ever to accurately diagnose and treat both dental and skeletal underbites, often without invasive surgery. Now that we have unpacked what an underbite really is, let's explore what causes it in the first place.
Underbites don’t just appear out of nowhere. There are a few common reasons why they develop. Some are beyond our control, while others can be prevented or corrected with the right care.
Sometimes, an underbite is simply part of the family tree. The shape and size of your jaw can be inherited, just like eye color or curly hair. If your lower jaw naturally grows a bit larger or your upper jaw is slightly smaller than average, your lower teeth can end up sitting in front of your upper teeth. Dentists call this a skeletal underbite. In many cases, genetics work hand-in-hand with environmental factors, like childhood habits or growth patterns, to influence how your bite develops. So, even if you are “born with it,” early treatment can still make a big difference.
Certain habits in the early years can slowly shape how your jaw grows. These include:
Over time, these habits can put gentle but constant pressure on teeth and jawbones, nudging them out of alignment. In some cases, the jaw may shift forward to find a more comfortable bite, which is also known as a functional underbite. It’s often easier to correct than one caused by bone structure.
Everyone’s face develops at a different pace. Sometimes, the lower jaw grows faster than the upper jaw, or the upper jaw doesn’t grow enough. This can cause a noticeable underbite as the bones mature. In rare cases, certain health conditions like Crouzon syndrome can affect how the middle part of the face develops, leading to a more pronounced underbite. Other factors, such as enlarged tonsils or blocked nasal passages, can also influence jaw position, since they may change the way a child breathes and holds their mouth over time.
No matter the cause, modern orthodontics offers more solutions than ever, from early interventions in children to advanced, non-surgical treatments for adults. Understanding why an underbite happens is the first step to finding the most effective fix.
Spotting an underbite is often simple. You can usually see when the lower teeth sit in front of the upper ones. But understanding exactly what is causing it and how severe it is takes a bit more detective work from a dental professional.
Your orthodontist starts with a visual exam to see how your teeth and jaws fit together when you bite down. From there, they use specialized tools to get a precise picture of your jaw alignment, including:
Not all underbites are created equal. Knowing the severity helps determine whether a patient can use braces or aligners alone, or if more advanced treatment is needed. Dentists classify them into three main categories:
Diagnosing an underbite begins with a physical exam, but today’s tools go much deeper. At the initial consultation in a Zenyum partner clinic, X‑rays and 3D intraoral scans capture the intricate structure of your teeth and jaw. This ensures the treatment plan reflects both bone alignment and tooth positioning accurately. Once the scan is complete, a 3D simulation helps visualize how your teeth will progress through treatment. This clear visualization empowers you to see what's possible and stay engaged throughout the process. Many orthodontic providers now combine digital scans with AI-driven treatment planning. improving speed, precision, and overall predictability.
Understanding how underbites are classified helps both patients and professionals choose the most effective treatment path.
In orthodontic terms, an underbite generally falls under Class III malocclusion, where the lower jaw (mandible) sits noticeably ahead of the upper jaw (maxilla). This often shows as the lower front teeth overlapping the upper ones, and can be caused by a forward-positioned lower jaw, a retruded upper jaw, or a combination of the two.
Orthodontists further categorize Class III underbites based on cause and treatment approach:
When it comes to treating an underbite, the best method depends on how early it is caught and how severe it is. Here's a breakdown that is easy to understand.
Read more: Understanding and Treating Underbite: A Comprehensive Guide
For young children whose bones are still developing, orthodontists often use appliances like palatal expanders and reverse-pull facemasks:
These methods are most effective between ages 7 and 12. A study found that using expanders with facemasks produced notable skeletal improvements, and even improved airway dimensions in early Class III (underbite) cases. Because children's bones are still growing, early treatment helps avoid more invasive methods later on.
If an underbite isn’t caught early or is milder, both braces and clear aligners offer non-invasive correction options:
For mild to moderate underbites, clear aligners can be highly effective. One study in the Journal of Clinical Orthodontics reported a 78% success rate in correcting Class III malocclusions using aligners. However, for severe skeletal underbites, aligners alone often aren’t enough. In those cases, braces or surgical options may be required.
Surgery typically comes into play when the underbite stems from bone structure issues, like a prominent lower jaw or underdeveloped upper jaw that braces or aligners can’t fully correct. In such severe skeletal cases, an orthognathic (jaw) surgery may be recommended to reposition the jaws properly. After surgery, braces or aligners help fine-tune tooth alignment.
Your journey to a straighter, more confident smile is simpler than you might think. Here’s how Zenyum makes it smooth, transparent, and even a little exciting every step of the way.
Read more: Your Ultimate Guide To Zenyum’s Free Smile Assessment
Getting started is simple- just visit the Zenyum website and tap “Start My Free Smile Check.” You’ll answer a few quick, friendly questions about your smile goals, then upload a few photos of your teeth from different angles. Don’t worry if you have never done this before! Our step-by-step guide will show you exactly how to capture the perfect shots using your phone.
Tip: Keep your bite natural and your jaw relaxed so our team can see your teeth just as they are in everyday life.
Once you’ve completed your online submission, the Zenyum team will help you book a visit with one of our trusted partner dentists or orthodontists. At this appointment, you will receive a thorough check-up, which may include X-rays or digital 3D scans to capture every detail of your teeth and jaw. This ensures your treatment plan is tailored to your needs from the very start.
Using your records, we design a customised treatment plan unique to your smile. You will see a realistic before-and-after simulation showing exactly how your teeth will move over time, and what your end result will look like. This is where your smile transformation starts to feel real.
Happy with your treatment plan? Once you give the green light, your aligners go into production. They are made to measure, using precision technology, so they fit snugly and work efficiently.
When your aligners are ready, we will book your fitting appointment. You’ll collect your entire set of aligners in one go, learn how to wear them, and get tips for keeping them clean and invisible.
From here, it’s simply a matter of wearing your aligners, following your plan, and watching your smile transform step by step. And the best part? The Zenyum team will be with you every step of the way- monitoring your progress, answering your questions, and making sure your treatment stays on track.
Answer a few questions, and take four teeth pictures. It only takes a few minutes!
Receive a call from us to schedule your dentist appointment
You’ll have 3D scans and X-rays taken of your teeth by your dentist
Give the green light for your Zenyum aligners to go into production after approved by your dentist.
