In a typical bite the upper front teeth close just in front of the lowers. An underbite, known clinically as a Class III relationship, reverses that: the lower incisors sit level with or ahead of the uppers, and the chin often appears prominent. The degree varies enormously, from a mild edge-to-edge bite that most people never notice to a lower jaw that projects several millimetres and affects the profile, chewing and speech. What makes underbite different from most other bite problems is that the cause is frequently skeletal, meaning the lower jaw has grown longer than the upper, rather than simply the teeth being in the wrong place. That distinction shapes what treatment can achieve. Tooth-borne problems can be corrected with aligners or braces; skeletal discrepancies can be camouflaged by moving teeth within limits, or corrected fully only by combining orthodontics with jaw surgery. Our Wimpole Street team assesses which type you have and is candid about what each route will and will not change.
Lower front teeth level with or in front of the upper ones
The defining feature; check in a mirror with back teeth together.
A prominent chin or a profile where the lower face looks long
Suggests the skeletal type, with a longer or forward lower jaw.
Upper front teeth that are worn, chipped or tilted forward
The reversed contact chips edges and can flare the upper incisors as the body compensates.
Difficulty biting through food with the front teeth
Incisors that do not overlap cannot shear.
Lisping or difficulty with certain sounds
Tongue and lip positions are altered by the jaw relationship.
Jaw that shifts forward as you close
A functional shift caused by a front tooth in crossbite; corrected more easily than a true skeletal underbite.
The strongest influence is genetic. A lower jaw that grows longer, or an upper jaw that grows less, runs in families and becomes more evident during the adolescent growth spurt, particularly in boys, whose jaws keep growing into the late teens.
In many Class III cases the lower jaw is normal and the upper jaw is set back or narrow. Cleft lip and palate repair in childhood can restrict upper jaw growth in the same way. This is important because expanding or advancing the upper jaw is often the more effective correction.
A single upper front tooth that erupts behind the lowers can force the jaw to slide forward to find a comfortable bite. The jaws may be normal, and correcting the crossed tooth allows the jaw to settle back.
Persistent tongue thrusting, mouth breathing and the loss of upper milk teeth early can tilt the balance of forces on the growing face. These are contributory rather than primary causes in most cases.
An underbite developing in adulthood, after the jaws have stopped growing, is unusual and may indicate a hormonal condition affecting bone growth. It is investigated medically rather than treated as a purely orthodontic issue.
These are holding measures, not a substitute for an examination. Use any pain relief exactly as directed on the pack and check with a pharmacist if you take other medicines.
Photographs, a digital scan, a cephalometric X-ray and a profile analysis distinguish a dental from a skeletal underbite and, in children, estimate how much growth remains. This is the basis for every decision that follows.
About this treatmentA face mask attached to an upper expander, or a functional appliance, can encourage forward development of the upper jaw between about seven and eleven, reducing the chance of surgery later.
About this treatmentWhere the jaws are close to normal, aligners tip the upper incisors forward and the lower incisors back to establish an overlap, sometimes with small elastics. From £2,950.
About this treatmentBrackets with elastics or the removal of a lower tooth on each side can retract the lower incisors enough to hide a moderate skeletal discrepancy without changing the jaw itself.
About this treatmentFor a marked skeletal underbite in an adult, braces align the teeth and a maxillofacial surgeon repositions one or both jaws. We refer and coordinate; surgery is usually available on the NHS where criteria are met.
Once the bite is corrected, chipped or shortened upper incisors are rebuilt with composite bonding or veneers.
About this treatmentAn orthodontic consultation at Wimpole Street with photographs, scans and X-rays is expected to be £95. Clear aligner treatment for a mild or moderate underbite is from £2,950, with the fee depending on complexity and duration; fixed braces are quoted after assessment. Retainers are included in the treatment fee.
Growth modification appliances for children are quoted individually. Where surgery is indicated, orthodontic preparation is done privately or through referral, and the surgical stage is usually NHS-funded with a hospital team; we explain the pathway in detail. Composite bonding to rebuild worn edges afterwards is from £395 per tooth, and veneers are indicative at £595 for composite and £1,095 for porcelain.
Figures are indicative prices for Wimpole Street and are confirmed in a written plan once a dentist has examined you. Fees match our South Kensington and St Paul's clinics.
Leave your details and we will be in touch when the Marylebone diary opens. If the problem cannot wait, the same clinicians are already seeing patients in South Kensington and at St Paul's.
Related conditions
Opening 1 October 2026
Wimpole Street is not yet seeing patients. Until then, please book or call our South Kensington clinic on 020 7183 2362 or our St Paul's clinic on 020 7183 3709. Questions about the new clinic: wimpolestreet@md.co.uk.
The same clinical team already works from two other Medical & Dental clinics. Book at either one now and, if you prefer, move your ongoing care to Wimpole Street once the doors open.
