Open Bite: When the Front Teeth Do Not Meet
For adults asking about an open bite, where the front teeth remain apart as the back teeth meet: its causes, measurement, why guidance puts habits first, and how often it returns. Relapse figures differ by study.
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Clinically reviewed by Dr Ibraheem Ijaz, dentist · GDC 301711
Medical disclaimer: This page is for general information only. It does not replace an examination or treatment by a dentist.
Dr Ibraheem Ijaz, principal dentist, reviewed this page. He is a General Dental Practitioner: BDS, BSc (Hons), MSc (Leeds), PG Dip Implant Dentistry, PG Cert Restorative and Aesthetic Dentistry.
What is an open bite?
In an open bite, the front teeth remain apart when the back teeth meet, the British Orthodontic Society (BOS) says. The tongue is often visible between them.
The clinical term is anterior open bite: a lack of vertical overlap of the upper and lower front teeth, Cochrane's 2014 review says.
What causes an open bite?
An open bite has several possible causes, a 2011 overview says: an inherited skeletal pattern, soft tissue effects and digit sucking. It says more significant open bites, sometimes reaching back to the last molars, rarely resolve on their own and often need complex orthodontic treatment or even jaw surgery.
Thumb sucking and other habits
A BOS advice sheet reviewed in 2023 calls sucking habits the most common cause of anterior open bites in children, and says they are so common in babies as to be considered normal. It says most children stop by around 4, concerns start if a habit persists beyond age 7, and effects on the teeth are more likely past 6 hours a day.
Skeletal open bite
One trial in a Cochrane review defined a skeletal open bite by a steep lower jaw plane, increased lower face height or a large jaw angle.
How is an open bite measured?
The Index of Orthodontic Treatment Need (IOTN), used for adult teeth, grades an open bite in millimetres.
Over 2 mm and up to 4 mm is grade 3 ("borderline need"). BOS's 2023 guide puts grade 4 ("need treatment") at over 4 mm. A 2015 guide on the NHS England site prints over 6 mm for grade 4; BOS's copy prints over 4 mm.
Why does guidance put habits before open bite treatment?
BOS says comprehensive orthodontic treatment should not start until a sucking habit has completely stopped. Its patient leaflet, reprinted in 2019, says treatment is otherwise unlikely to be successful.
BOS's advice sheet suggests reward charts, and barriers such as plasters, thumbguards or bitter nail varnish. It advises against nagging, teasing or punishing a child.
Cochrane's 2015 review of six trials on digit habits and 252 children, searched to October 2014, found low-quality evidence that psychological approaches and two appliance types help children stop. All were at high risk of bias, and data on upset and eating difficulty were inconclusive.
A habit breaker appliance makes thumb sucking more difficult, BOS's leaflet says. Its advice sheet warns against prolonged use because of hard and soft tissue risks. Its 2023 guide finds such appliances less valuable than gentle dissuasion and advice at the baby to mixed teeth stage. Its 2019 advice for dentists says they are usually only used in older patients resistant to more conventional techniques.
To ask about orthodontic treatment, book online or call 0114 288 2121.
What does evidence say about correcting an open bite in children?
Cochrane's 2014 review, searched to February 2014, calls the evidence weak. Two of its three trials corrected an open bite against no treatment, none reported stability, and the third interrupted one appliance early after side effects in four of ten users. It says clinical recommendations cannot be made on these trials alone.
A 2017 review of 11 controlled trials in growing children and adolescents, most with relevant limitations, finds one habit appliance type appears effective in the short term (overbite +3.1 mm). It says most dental effects are seemingly lost with time, and skeletal effects are still controversial.
A 2023 review of five studies in children aged 4 to 12 reports self-correction after a sucking habit stops, with improvement from 50% to full, at very low certainty and with no clear upper age. BOS's sheet says it is less likely if a habit persists beyond age 7, and after age 12.
What does guidance say about an open bite in adults?
BOS's adult guide calls an open bite a complex problem to treat that may require jaw surgery.
The Index of Orthognathic Functional Treatment Need, published in 2014 for severe problems not amenable to orthodontics alone, scores functional need only. An open bite of 4 mm or more scores 5, very great need. Under 4 mm it scores 4 with functional difficulties and 3 without.
A 2011 overview lists surgical risks including pain, swelling, bruising, altered nerve sensation and occasionally lasting numbness.
How often does an open bite come back after treatment?
Relapse risk is reported differently by study, treatment and definition, so each figure stands alone.
| Study | Patients | Mean follow-up | Counted | Result | Comparison |
|---|---|---|---|---|---|
| 2011 meta-analysis, 21 case series in all: non-surgical | Mean age 16.4 | 3.2 years | Positive overbite at 12 months or more | 75% stable | None |
| Same: surgical | Mean age 23.3 | 3.5 years | Same | 82% stable | None |
| 2003, non-surgical, no extractions | 21 | 5 years | "Clinically stable" | 61.9% | Normal bites, changes over time |
| 2004, non-surgical, extractions | 31 | 8.35 years | "Clinically stable" | 74.2% | Normal bites, changes over time |
| 2010, surgery with orthodontics | 39, mean age 20.83 | 8.22 years | Negative overbite | 35.9% relapsed | Class I and II against Class III |
The 2011 authors urge caution, as the case series lacked controls and varied, and say the groups cannot be compared directly. Those series are unnamed in the abstract, so the rows may overlap. The 2003 and 2004 abstracts do not define "clinically stable". A 2006 comparison (also 21 and 31 patients) found steadier overbite with extractions, but no significant difference in clinically significant relapse. The 2010 study's stability was 47.82% in Class I and II and 87.5% in Class III.
A 2023 review of six controlled studies compared 134 non-surgically treated people, about age 8 where reported, with 110 untreated. On skeletal angles, not relapse, three studies showed no significant difference after treatment. It reads this as relative stability, with caution. It concludes long-term influence on skeletal tissues and front tooth angle is rather minimal.
What do guidance and studies say about retention after an open bite?
BOS says keeping any habit stopped is essential in the retention phase, to avoid significant relapse. Its undated retainer page says teeth tend to move back towards their original positions. See how teeth move, and retention after treatment for retainers in general.
In a 2015 study of 37 patients, mean age 18, with fixed retainers in place, six had an overbite of 0 mm or less a mean of 4 years 2 months after treatment. Without controls, the authors concluded fixed retainers were not thoroughly successful, and extractions made no significant difference to overbite change.
Who is orthodontic treatment at Deepcar Dental Care for?
Orthodontic treatment at Deepcar Dental Care is for adults only.
See orthodontics at Deepcar Dental Care for the treatments offered.
Frequently asked questions
Can braces fix an open bite?
It depends on the case, in general. RCS England's 2013 guide reports a tentative suggestion that open bites under 2.5 mm may be similarly stable with surgery or orthodontics alone, without controlled studies to confirm it. It says clinicians have become more cautious.
Is tongue thrust the cause of an open bite?
That is unresolved. A 2025 narrative review of nine studies calls the cause-and-effect link controversial, and says it is unclear whether the tongue's influence is a primary cause, an influencing factor or just a consequence of an existing open bite.
Can orofacial myofunctional therapy help an open bite stay closed?
Evidence is limited. In a 2010 study of 76 people, measured 2 months to 23 years after treatment, relapse averaged 0.5 mm with the therapy plus orthodontics and 3.4 mm without, but that group was chosen for having relapsed. A 2025 scoping review says its effectiveness could not be conclusively confirmed, though it remains plausible.
Can an open bite affect eating or speech?
For eating, it can. BOS's adult guide says difficulty biting food is very often more of an issue than appearance. On speech, its 2023 sheet says sucking habits can have some effect, though not a linear one. If biting food is difficult, show a dentist.
How common is an open bite?
Figures vary by study. A 2018 review of 53 population studies averaged 4.93% with adult teeth and 5.29% with mixed teeth, counting overbite below 0 mm. A 2022 review of 26 studies gave 16.52% in ages 2 to 16, at very low certainty.
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