What Is an Underbite?
In a healthy bite, the upper front teeth sit slightly in front of the lower front teeth. The upper arch overlaps the lower like a lid over a box. In an underbite, also called a Class III malocclusion, that relationship is reversed: the lower front teeth and often the lower jaw itself sit forward of the upper.
Approximately 5% of the population is affected, and among all forms of malocclusion, underbite carries the strongest genetic influence. If a parent, grandparent, or sibling had an underbite or jaw surgery, the odds that a child in the family will develop one are significantly higher.
Underbite is not a single condition with a single fix. The cause can be purely dental (only the teeth are tipped wrong), purely skeletal (the jawbones themselves are mismatched), or a combination of both.
That distinction is the most important call an orthodontist makes on this diagnosis, because it determines whether braces alone will do the job, whether growth modification can redirect the jaw in a child, or whether orthognathic surgery will be part of the plan in an adult.
A child who is seven and still growing has options an adult of thirty does not.
Three Types of Underbite
Dr. Viecilli uses CBCT imaging and Medit i700 digital scans to classify the underbite before any treatment is recommended. Skipping this step is the single most common source of over-treatment. A dental underbite does not need the same appliance as a skeletal one, and a skeletal case in an adult cannot be solved with the same tools used in a growing child.
Dental Underbite
The jawbones are correctly sized and positioned, but the upper teeth are tipped backwards (retroclined), the lower teeth are tipped forward (proclined), or both. The skeletal relationship is normal underneath. Treatment: braces or clear aligners reposition the teeth. This is the simplest form and can be corrected at nearly any age.
Skeletal Underbite
The jawbones themselves are mismatched. Either the upper jaw (maxilla) is underdeveloped, the lower jaw (mandible) is overgrown, or both. This is the most common form, the one with the strongest genetic link, and the one most sensitive to treatment timing. In growing children, facemask therapy plus palatal expansion can redirect growth.
In adults, the choice is orthodontic camouflage or orthognathic surgery.
Combined (Most Common)
Skeletal and dental components are both present. The jaws are mismatched, and the teeth have compensated by tipping in the opposite direction. The body’s attempt to bring the teeth together despite the jaw discrepancy. Treatment must address both layers: the bone first (in children), then the teeth, or a surgical-orthodontic coordinated plan in adults.
The Critical Treatment Window: Ages 7–10
For skeletal underbites, the single most important variable in treatment outcome is timing. Between ages 7 and 10, the midpalatal suture. The cartilaginous seam that runs along the roof of the mouth. Is still open, and the maxilla is responsive to protraction forces transmitted through the upper jaw.
This is the window when a facemask (reverse-pull headgear) combined with a bonded palatal expander can physically pull the upper jaw forward and redirect facial growth. It is a narrow window, but when it is used well, it can turn a case that would otherwise require surgery into one that needs only braces.
The window closes around age 12–14. Once the midpalatal suture fuses, the maxilla becomes a single rigid bone and can no longer be pulled forward with external appliances alone. After fusion, options narrow to orthodontic camouflage (which disguises the discrepancy by tipping teeth) or orthognathic surgery (which physically repositions the jaws). This is why the American Association of Orthodontists recommends a first evaluation by age 7. And why, for underbite specifically, “watching and waiting” past age 10 is rarely advisable.
What the Research Shows
A 2024 Cochrane systematic review (29 studies, 1,169 children) found that facemask therapy improved both the bite and the underlying jaw relationship immediately after treatment. Long-term follow-up is more nuanced: skeletal improvements tended to diminish by the three-year mark and appeared largely lost by six years.
However, clinicians consistently judged that children who received early facemask treatment were less likely to require orthognathic surgery in adulthood. Early intervention does not always permanently eliminate the jaw discrepancy, but it very often reduces its severity enough that an adult-stage surgical plan becomes unnecessary.
Family History Matters – Often More Than the Bite Itself at Age 7
Among all forms of malocclusion, underbite has the strongest hereditary pattern. When a parent or grandparent has an underbite or a history of jaw surgery, a child’s risk of developing one is significantly elevated.
A child’s bite at age 7 may still look acceptable even when the underlying growth pattern is already pointing toward Class III. The lower jaw continues to grow through puberty and can outpace the upper jaw, turning a subtle age-10 tendency into a severe age-15 problem.
When there is family history, Limestone Hills recommends that the evaluation happen no later than age 7, regardless of how the child’s bite looks at the time.
Why Limestone Hills Treats Underbite Early. And Why Restraint Still Matters
Dr. Viecilli only recommends early treatment when waiting would cost more time, money, or surgical risk later. Most children are better served by monitored growth observation until permanent teeth emerge and skeletal patterns stabilise. When early intervention is warranted, the clinical reason is specific: a crossbite causing asymmetric jaw growth, a severely impacted canine path, an airway-driven palatal narrowing, or a habit (thumb, tongue thrust) that will reshape the bite if left uncorrected. Limestone Hills runs a free Growth Observation Program for children who need monitoring rather than immediate treatment.
In practical terms, for an underbite: a confirmed skeletal Class III in a 7–10-year-old is one of the clearest indications for Phase 1 treatment. A mild dental tip in a child whose jaws are otherwise well-related often is not. The right answer there can be a complementary growth-observation recall every six months, rather than an immediate application. The diagnosis drives the decision.
Treatment Options by Age at Limestone Hills
Children Ages 7–10: Facemask Plus Palatal Expansion (Phase 1)
The gold standard for skeletal underbite in a growing child is the facemask + palatal expander combination. A bonded expander is placed first to widen the upper jaw and loosen the midpalatal suture. The facemask. A padded framework that rests on the forehead and chin. Is worn at home and connected to the expander with elastic bands.
Those elastics apply a steady forward pull on the maxilla, redirecting growth of the upper jaw into a more normal anterior position relative to the lower.
At Limestone Hills, a typical Phase 1 underbite protocol runs roughly six to twelve months: two to three weeks of active expansion, followed by retention of the expander while the facemask does its skeletal work, then removal once the bite is corrected and over-corrected slightly to account for continued mandibular growth.
Facemask wear is asked for during evenings and overnight. Approximately 12–14 hours per day. And children adapt faster than most parents expect. The appliance is removed for school, sports, and meals.
Reverse Twin Block and Alternative Protocols
Not every child tolerates a facemask, and not every case needs one. For mild-to-moderate skeletal Class III presentations, a reverse twin block or similar removable functional appliance can redirect growth using intraoral forces alone.
These appliances are often better tolerated socially because nothing sits outside the mouth, and in cooperative patients, they can produce meaningful skeletal change. Dr. Viecilli selects the appliance based on the severity of the skeletal discrepancy, the child’s dental development, and. Honestly.
The family’s assessment of what the child will actually wear consistently.
Teens: Braces, Class III Elastics, and Watchful Monitoring
Once the growth window has closed, the skeletal component cannot be changed without surgery. Treatment shifts to dental compensation: braces align the teeth, and Class III elastics (rubber bands stretched from the upper back teeth to the lower front teeth) tip the upper teeth forward and the lower teeth back relative to the jaws.
For teens with severe underlying skeletal underbites who are still growing, watchful monitoring through puberty is essential. If the lower jaw continues to outgrow the upper, a surgical plan may become necessary once skeletal maturity is reached.
Waiting to make the final call until growth is complete protects the patient from committing to surgery prematurely.
Adults: Camouflage or Orthognathic Surgery
Orthodontic camouflage is appropriate for adults with mild skeletal underbites. Braces or clear aligners tip the upper front teeth forward and the lower front teeth back, disguising the jaw discrepancy at the dental level. The jaws themselves do not move.
This works well when the skeletal discrepancy is small (ANB within one to two degrees of normal), the facial profile is acceptable to the patient, and there is no significant functional problem from the bite itself.
Orthognathic surgery is the correct choice for moderate-to-severe adult skeletal underbites. A Le Fort I osteotomy advances the upper jaw, a bilateral sagittal split osteotomy sets back the lower jaw, or both procedures are combined, depending on the analysis.
Orthodontic treatment is done before surgery to align the teeth into position for the jaws to meet correctly after repositioning, and a second phase of orthodontics refines the bite after healing. , whose CAGS training includes the surgical orthodontic workflow, coordinates these cases directly with Austin-area oral and maxillofacial surgeons. Limestone Hills handles the pre-surgical and post-surgical orthodontics in-house; the surgery itself is performed at the surgeon’s facility.
Where’s the Real Surgery-vs-Ortho Threshold for an Adult Underbite?
Dr. Viecilli refers a deep bite for orthognathic surgery evaluation when the CBCT confirms a severe skeletal Class II pattern in a non-growing patient, and camouflage with braces or aligners would either fail to produce a stable result or compromise the facial profile in ways the patient cannot live with. Most cases that look severe to the patient are still correctable with orthodontics alone, and the practice opens that conversation explicitly so patients are not pushed toward surgery that the imaging and clinical findings do not require. When surgery is the right answer, Limestone Hills handles the pre- and post-surgical orthodontics and partners directly with an oral and maxillofacial surgeon who handles the surgical fees and pre-authorisation separately.
For an underbite specifically, that patient-centred workup looks like this: the doctors ask what the patient is bothered by. The bite, the profile, the chewing, all three. Then run the iOrtho aligner simulation and CBCT analysis to see how far dental compensation can realistically go.
If camouflage solves the functional complaint and the patient accepts the profile, camouflage wins. If the profile itself is the complaint, or the skeletal discrepancy is severe enough that compensation would put the front teeth out of the supporting bone, surgery is the honest recommendation.
The conversation is explicit; neither option is soft-sold.
What Happens If an Underbite Is Not Treated
Worsening During Puberty
The lower jaw has its largest growth spurt between ages 12 and 16. When the mandible is already long relative to the maxilla, puberty amplifies the discrepancy rather than balancing it. An underbite that was cosmetically mild at age 10 can become functionally severe by age 15. And by then, the window for non-surgical growth modification has closed.
Accelerated Tooth Wear
Reversed bite contact loads the upper front teeth against their facial (front) surface rather than the lingual (back) surface they were designed to meet. The enamel on the facial side of upper incisors is thinner, and the forces travel in an unintended direction. Over the years, this produces visible wear, chipping, and sensitivity on the upper front teeth.
TMJ Strain and Chronic Jaw Pain
A reversed bite forces the jaw joint into an abnormal closing position. The muscles and ligaments surrounding the joint compensate constantly, and chronic compensation is how many adult TMD cases begin. Clicking, locking, headaches referred from the temporalis and masseter, and limited opening range are typical downstream symptoms.
Many patients who end up on the TMJ page started with an untreated Class III bite.
Speech and Chewing Efficiency
An underbite affects the articulation of “s” and “z” sounds (a frontal lisp) because the tongue cannot close against the upper incisors in the expected way. Chewing efficiency drops because the incisors. The shearing teeth. Cannot cleanly cut through food when they meet edge-to-edge or in reverse.
Patients often adapt by chewing exclusively with the molars, which loads those teeth beyond what they were meant to carry.
Facial Profile and Self-Image
A skeletal underbite produces a characteristic concave facial profile: the midface appears flat or sunken, the upper lip loses support, and the chin juts forward. The effect becomes more pronounced as the face matures, because the mandible continues to remodel into late adolescence. For many adults, the profile itself.
Not the chewing difficulty or the tooth wear. Is what finally drives them to seek treatment. It is a conversation Limestone Hills has often, and one the doctors are careful to hold honestly: what ortho can do, what surgery can do, and what each looks like in the mirror at the end.
Treatment Options Comparison
| Treatment | Best For | Mechanism | Price |
|---|---|---|---|
| Facemask + Expander | Children ages 7–10, skeletal | Forward pull on maxilla, midpalatal expansion | Phase 1 fee |
| Reverse Twin Block | Children, mild-moderate skeletal | Intraoral functional appliance | Phase 1 fee |
| Metal Braces | Dental or mild skeletal, teens/adults | Tooth movement + Class III elastics | 4,000 |
| Clear Ceramic Braces | Dental cases, aesthetic preference | Same mechanics as metal | 4,600 |
| Invisalign | Mild dental underbite, adult preference | Aligners + Class III elastics | 4,700 |
| Angel Aligners Lower Entry | Mild dental underbite | Aligners + Class III elastics | 4,000 |
| Orthognathic Surgery + Braces | Moderate/severe adult skeletal | Le Fort I, BSSO, or bimaxillary; coordinated with the oral surgeon | Coordinated with the surgeon |
Typical Treatment Timeline
| Stage | Duration | What Happens |
|---|---|---|
| Records & classification | 1–2 visits | Digital scans, CBCT, family history, dental vs skeletal determination |
| Phase 1 (ages 7–10, skeletal) | 6–12 months | Expander + facemask; active forward pull on maxilla |
| Growth monitoring | Every 6–12 months until skeletal maturity | Track mandibular growth through puberty; adjust plan if lower jaw outpaces upper |
| Phase 2 / comprehensive | 18–24+ months | Braces or aligners with Class III elastics to align teeth in the corrected skeletal position |
| Surgical cases (adults) | 9–12 months pre-op, surgery, 6–9 months post-op | Pre-surgical orthodontics at Limestone Hills, surgery with oral surgeon, and post-surgical refinement |
| Retention | Nights indefinitely | Underbite has a real relapse tendency; long-term retention is not optional |
What to Expect at Your Consultation
Digital Intake
Family history of underbite (critical for this diagnosis), medical history, and patient-stated concerns. Bite function, chewing, speech, profile.
Comprehensive Records
Medit i700 digital scan, clinical photographs, free 3D CBCT for skeletal classification.
Classification
Dental, skeletal, or combined. Determined on the CBCT and confirmed clinically. For growing children, the growth window is mapped explicitly.
Treatment Options Presented with the Surgical vs Ortho Threshold Explicit
For adults, the camouflage vs surgery conversation is held honestly at the first visit. Not hidden inside a treatment plan. Surgical coordination cases are reviewed in detail before any commitment.
Exact Pricing and Financing
Phase 1 fee (if indicated), comprehensive fee, or pre/post-surgical orthodontic fee with the surgical coordination pathway clearly explained.
Before & After
How Much Does Underbite Treatment Cost?
Phase 1 (facemask + expander, ages 7–10): fee set at consultation, typically well below comprehensive
Orthognathic surgery: The surgical fee is separate and billed by the oral and maxillofacial surgeon. Most medical insurance plans cover orthognathic surgery when functional impairment is documented. Limestone Hills assists with medical necessity letters and pre-authorization.
Expansion appliances (RPE for Phase 1 skeletal cases) are typically an add-on of approximately $500. For adult skeletal cases where MARPE is indicated, the MARPE fee range is $4,000 and is included within the comprehensive adult plan.
Insurance & Financing
Limestone Hills accepts most PPO dental insurance plans and offers in-house financing with 0% APR for families who qualify. Third-party options (Cherry, CareCredit) are also available for patients who prefer a longer term, and a pay-in-full discount applies when the full fee is paid at the start of treatment. Insurance details · Discounts.
Common Appliances Used at Limestone Hills
In growing children, a palatal expander paired with a reverse-pull facemask redirects jaw growth during the window when bone is still responsive, often eliminating the need for surgery later. For adults whose growth is complete, Dr. Viecilli coordinates orthognathic jaw surgery alongside braces to correct the skeletal discrepancy that aligners and braces alone cannot resolve.