Protruding Front Teeth: Increased Overjet and Trauma Risk
For adults asking about protruding front teeth: what increased overjet means, how it is measured, its link with front tooth injury, treatment timing evidence by age and mouthguards. Studies associate larger overjets with higher odds of front tooth injury.
5.0 from 550+ Google reviews
Open 8am to 8pm, seven days
Free parking at the door
CQC & GDC registered
No referral needed
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 does increased overjet mean?
An increased overjet means the upper front teeth sit further forward of the lower front teeth than usual, so they look prominent.
The British Orthodontic Society (BOS) calls protruding upper front teeth one of the most common dental problems. Overjet differs from an overbite, the vertical overlap.
Cochrane's 2018 review background says prominent upper front teeth, Class II division 1 in its trials, may come from any combination of jaw, tooth and lip position and, among jaw positions, more usually a lower jaw too far back. Thumb sucking can also contribute.
How is an overjet measured?
An overjet is measured in millimetres, front to back, between upper and lower front teeth. A 2015 guide hosted on the NHS England site lists 2 to 4 mm as average for adult teeth.
BOS's 2023 guide prints the Index of Orthodontic Treatment Need (IOTN) grades, used for adult teeth. Over 3.5 mm and up to 6 mm is grade 2 ("little") with competent lips and grade 3 ("borderline need") with incompetent lips, which do not rest together. Over 6 mm and up to 9 mm is grade 4, and over 9 mm grade 5, both "need treatment".
Is a larger overjet linked to front tooth injury?
Yes, as an association. A 2022 British Dental Journal paper links increased overjet with higher odds of front tooth injury at all ages and dental stages.
| Study and people | Overjet cut-off | Odds ratio (95% CI) |
|---|---|---|
| 2015 review (54 studies overall: children, adolescents and adults), adult teeth | 3 to 4 mm | 2.01 (1.39 to 2.91) |
| Same review | 6 ± 1 mm | 2.24 (1.56 to 3.21) |
| 2019 review (41 studies overall), children, mixed and secondary teeth | Over 5 mm | 2.43 (1.34 to 4.42) |
| Same review: age 12 | Over 5 mm | 1.81 (1.44 to 2.27) |
| 2020 Geneva study: 1,413 children aged 6 to 13, followed 1 year | 6 mm or more | 3.37 (1.81 to 6.27) |
The review abstracts do not word the comparison group. Geneva compared 6 mm or more with smaller overjets: 14 of 98 such children had a new injury, among 76 of all 1,413.
Among 1,137 children aged 11 and 12, inadequate lip coverage was the most important independent predictor of injury, and much of overjet's predictive value may be explained by it.
What does evidence say about when to treat an increased overjet in children?
Evidence of low to moderate quality suggests early treatment is more effective for reducing incisal trauma than later treatment, Cochrane's 2018 review says. There appear to be no other advantages.
Searched to September 2017, it compared two phases, starting at 7 to 11, with one course at about 12 to 16. New incisal trauma affected 31 of 161 with early functional appliance treatment against 51 of 171 with late treatment (odds ratio 0.56, 95% CI 0.33 to 0.95, moderate quality). With headgear it was 24 of 117 against 44 of 120 (odds ratio 0.45, 95% CI 0.25 to 0.80, low quality).
The 2022 paper pooled four trials, adding a Swedish one: 14.2% early against 25.5% late (odds ratio 0.48, 95% CI 0.28 to 0.81). It advises caution because effects varied widely, notes no trial made trauma its primary outcome and calls the evidence low to moderate quality. It says early treatment takes longer and involves more appointments.
The paper reports the largest effect in the Swedish trial, with very little weight (5.3%) and most of its trauma before enrolment. Whether its cases were new is unclear. That trial's abstract (60 children, mean age 9.5) reports no evident effect on trauma against untreated controls, and lack of cooperation left treatment unsuccessful for 27% of patients.
On growth timing, BOS's 2023 guide for dentists says patients who would benefit from a functional appliance should be referred before their growth spurt. The 2022 paper says factors that might influence the decision to start early include an overjet over 10 mm, being bullied, and being female, as girls enter the growth spurt earlier.
To ask about orthodontic treatment, book online or call 0114 288 2121.
What does evidence say about growth modification in children and adolescents?
Growth modification aims to alter facial growth while young, and Cochrane's review, searched to September 2017, covers people under 16.
Against no treatment, low-quality evidence suggests late treatment in adolescence with functional appliances is effective for reducing the prominence of upper front teeth. On ANB, an angle showing how the jaws relate, one appliance type showed no evidence of a difference and the other seemed to reduce it, also low quality. Once early and late groups had finished, final overjet and ANB did not differ with functional appliances, and showed no evidence of a difference with headgear, on low to moderate quality evidence. The review did not search separately for adverse effects. The 2022 paper warns against advocating early treatment for all on the idea of enhanced facial growth.
What does guidance say about orthodontic treatment for adults?
BOS's 2023 guide says it would be wrong to advise adults that orthodontic treatment is not possible for them.
It says treatment takes several months longer than the equivalent for a child, as adult teeth move less readily through denser bone, and that adult orthodontics is more complex and demanding. Cochrane's under-16 trials support no growth modification claim for adults.
How can front teeth be protected while an overjet remains?
Mouth protection, particularly during contact sports, is among the measures the 2022 paper names for children with an increased overjet. Ultimately, it adds overjet reduction with orthodontic treatment.
A 2019 review of 26 sports studies, with multiple methodological weaknesses, found orofacial injury more likely without a mouthguard in 12 cohort trials (risk ratio 2.33, 95% CI 1.59 to 3.44). Its concussion result was modest (1.25, 95% CI 0.90 to 1.74). Its stated criteria do not mention overjet. Read more about sports mouthguards.
The NHS says you can usually save a knocked-out tooth by putting it back in place, or in milk, as soon as possible, but never put a baby tooth back in. Ask for an emergency dentist appointment, even if you cannot find the tooth; an adult tooth needs treating within 30 minutes to 1 hour, if possible. If you do not have a dentist or cannot get an emergency appointment, call 111. See knocked-out tooth for first steps.
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
Are buck teeth the same as an increased overjet?
Usually, yes. Buck teeth is an everyday name for upper front teeth that stick out, and overjet is the measurement behind it. BOS's adult guide says a lower jaw too far back can make upper teeth appear to stick out.
Does an overjet change with age?
It can. BOS's 2023 guide says small overjets become larger from baby to adult teeth. Casts of 51 people, taken at 15 and 27, showed overjet diminished, and incisal wear increased. A 2026 paper's background says untreated adults' overjet generally remains stable.
Are protruding front teeth linked to bullying?
They have been linked. Among 336 adolescents aged 10 to 14 referred for orthodontic assessment at three UK hospitals, being bullied was associated with increased overjet. The 2022 paper adds that early correction does not seem to influence oral health-related quality of life.
How serious are front tooth injuries?
Severity varies. Among Geneva children, new injuries included 39% enamel-dentine fractures and 32.1% loosened, displaced or knocked-out teeth. A US survey of children and adults found incisor trauma prevalent but mostly limited to enamel. For a knocked-out tooth, the NHS says ask for an emergency dentist appointment, or call 111 if you have no dentist or cannot get one.
How common are protruding front teeth?
About a quarter of 12-year-olds in the UK are affected, Cochrane's 2018 review background says. A 2018 review of population studies, counting over 3 mm as increased, averaged 20.14% for adult teeth, ranging from 1.6% to 48.4% by study.
Book a consultation.
Online in under a minute, or call and speak to a real person.
For other bite and alignment problems, browse this section. See our patient reviews page.
334 Manchester Road
Deepcar, Sheffield S36 2RH
0114 288 2121
Contact us
Opening hours
Open 8am to 8pm, seven days
Free parking at the door