---
title: "Bimaxillary Proclination UK | Treatment & Outcomes (2026)"
url: https://virtualconsultant.online/guides/bimaxillary-proclination-treatment-uk
description: "Bimaxillary proclination — both upper and lower front teeth tipping forward — causes a convex lip profile. UK guide to diagnosis, premolar extractions."
updated: 2026-08-17T00:00:00Z
publisher: Virtual Consultant Online
---

Bimaxillary Proclination

Incisor Inclination

Extraction Orthodontics

# Bimaxillary Proclination: When Both Upper and Lower Teeth Stick Out

Bimaxillary proclination describes a pattern where both the upper and lower front teeth are tipped forward at an angle steeper than normal. Unlike a simple overjet, both arches are involved, and the underlying jaw relationship is often Class I. Understanding whether proclination is within ethnic norms — or genuinely requires treatment — is one of the more nuanced assessments in orthodontics.

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## What is bimaxillary proclination?

Bimaxillary proclination — sometimes called bimaxillary protrusion — occurs when both the upper and lower incisors are labially inclined beyond the accepted cephalometric norms for the individual's skeletal pattern and ethnic background. The upper incisor to maxillary plane angle and the lower incisor to mandibular plane angle are both increased. Unlike a straightforward Class II overjet, where only the upper teeth protrude relative to a retruded lower jaw, bimaxillary proclination involves both arches equally — the overall jaw relationship (skeletal pattern) is typically Class I, but the dental bases are both tipped forward.

## How does it differ from a simple overjet?

In a Class II Division 1 malocclusion with increased overjet, the upper incisors protrude but the lower incisors are often upright or retroclined, and the underlying jaw relationship is typically Class II — meaning the lower jaw sits further back than ideal. In bimaxillary proclination the overjet may be relatively normal because upper and lower incisors are both proclined by a similar degree. The profile shows lip protrusion — a convex soft-tissue profile with the lips often sitting in front of the E-line (Ricketts' aesthetic plane). This is a key distinction: both the bony and dental components are positioned anteriorly as a unit.

## Ethnic variation and the question of normalcy

Cephalometric norms developed historically from white European populations and do not apply universally. Research consistently shows that people of Afro-Caribbean, South-East Asian, and South Asian descent have significantly higher incisor inclinations and more anteriorly positioned lips that are completely normal within their ethnic group. Applying Caucasian norms to these patients risks over-treating a natural variation. Orthodontists use ethnicity-specific cephalometric standards and individualised norm tables to distinguish genuine proclination requiring treatment from natural variation. Patients referred for treatment should ask whether the assessment accounts for their ethnic background.

## Clinical assessment — cephalometrics and lip competence

Assessment involves a lateral cephalometric radiograph to measure upper and lower incisor inclinations, the inter-incisal angle, and the relationship of the dentition to the facial skeleton. Key measurements include the upper incisor to maxillary plane angle (norm approximately 109 degrees), the lower incisor to mandibular plane angle (norm approximately 92 degrees), and the lower incisor to A-Pog line. Lip competence — whether the lips meet at rest without muscular strain — is assessed clinically. Incompetent lips that require effort to close, or lips resting between the teeth (lip trap), suggest significant proclination. Soft-tissue profile analysis assesses lip position relative to the E-line and S-line. Profile photographs and standardised records are taken before any treatment planning.

## Treatment planning considerations

Treatment is indicated where proclination is outside ethnic norms, where lip incompetence causes dryness and speech effects, where the profile is a significant concern to the patient, or where a lip trap is causing damage to the periodontal tissues. Where proclination is mild and within ethnic norms, no treatment is needed. A frank discussion about the trade-off between treatment duration, the need for extractions, and the likely improvement in profile should precede any commitment to treatment. Orthognathic surgery is not typically required for bimaxillary proclination unless there is also a significant underlying skeletal Class II or Class III component.

## The premolar extraction approach

The standard treatment for genuine bimaxillary proclination involves the extraction of four premolars — typically the first premolars from each quadrant — to create space for retracting both the upper and lower incisor segments. Fixed appliances are used to close extraction spaces and tip or bodily retract the incisors back into a more upright position. The treatment aims to reduce incisor inclination, decrease lip protrusion, and achieve lip competence. Extraction decisions depend on the degree of proclination, the crowding present, and how much retraction is realistically achievable with the available anchorage.

## TAD-assisted retraction

Skeletal anchorage using temporary anchorage devices (TADs) or miniscrews allows greater and more controlled incisor retraction than conventional anchorage provided by the molars alone. In cases requiring maximum anchorage — where significant retraction is needed without losing posterior tooth position — TADs are inserted into the interradicular bone and used to provide absolute anchorage for retraction mechanics. This approach is particularly valuable in bimaxillary proclination where both arches need substantial retraction. TADs typically remain in place for 6 to 18 months and are removed at the end of treatment under local anaesthetic.

## Lip trap consequences

A lip trap occurs when the lower lip habitually rests behind the upper incisors, applying pressure that forces the upper teeth further forward while restraining the lower incisors. This is both a cause and a consequence of increased overjet and proclination. Untreated, a lip trap perpetuates and worsens the proclination over time. Correcting the incisor position typically resolves the lip trap. In children, early interception of habits and myofunctional appliances may reduce the severity of proclination before comprehensive orthodontic treatment is undertaken.

## Stability and retention

Bimaxillary proclination cases require careful retention planning. The retracted incisors are under pressure from the lips and tongue, and without adequate retention there is a tendency for teeth to drift back towards their original positions. Permanent bonded retainers on both upper and lower incisors are strongly recommended following treatment, supplemented by removable retainers worn at night. Patients should be counselled from the outset that retention is lifelong — removing retainers after a few years increases the likelihood of relapse.

## NHS vs private treatment in the UK

NHS orthodontic treatment for bimaxillary proclination is available to eligible under-18s where the IOTN score meets the threshold (grade 4 or 5). Incisor proclination contributing to increased overjet, lip incompetence, or soft-tissue injury can contribute to a high IOTN score. Adults and those with borderline IOTN scores are typically treated privately. Private treatment costs for extraction cases with fixed appliances range from approximately £3,000 to £6,000 depending on the practice and complexity. Cases requiring TADs add to this cost.

## Useful related pages

[Malocclusion Types and Classification](https://virtualconsultant.online/guides/malocclusion-uk)

[Tooth Extraction for Braces](https://virtualconsultant.online/guides/tooth-extraction-for-braces-uk)

[TADs and Miniscrews in Orthodontics](https://virtualconsultant.online/guides/tads-miniscrews-orthodontics-uk)

[Skeletal vs Dental Malocclusion](https://virtualconsultant.online/guides/skeletal-vs-dental-malocclusion-uk)

[Buck Teeth Treatment UK](https://virtualconsultant.online/guides/buck-teeth-treatment-uk)

This guide is for general information only. It is not a diagnosis, treatment plan, or substitute for advice from a registered dentist or orthodontist.

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### Frequently Asked Questions

Is bimaxillary proclination the same as buck teeth?

Not exactly. Buck teeth usually refers to protruding upper front teeth — a Class II overjet — where only the upper incisors are prominent. Bimaxillary proclination involves both upper and lower incisors tipping forward together, so the overjet may look relatively normal even though both arches are proclined. The soft-tissue profile looks different too — in bimaxillary proclination both lips protrude rather than just the upper lip.

Do I definitely need extractions to treat bimaxillary proclination?

In most cases of genuine bimaxillary proclination requiring treatment, yes — premolar extractions are needed to create the space for incisor retraction. Non-extraction approaches would leave the incisors proclined. However, the degree of extraction depends on severity; borderline cases may be treated with extractions in one arch only. Your orthodontist should discuss the options and the expected outcome for each.

Can clear aligners treat bimaxillary proclination?

Clear aligners can manage some degree of incisor retraction following premolar extractions, but cases requiring significant bodily retraction with maximum anchorage are generally better managed with fixed appliances and TADs. Aligner mechanics for large retraction movements are less predictable than fixed appliance approaches. Some practices offer hybrid approaches. Discuss this specifically with your orthodontist given the amount of movement required.

Will treating bimaxillary proclination change my face?

Yes — reducing the proclination typically reduces lip protrusion and creates a flatter soft-tissue profile. For most patients this is the goal, but the change can feel noticeable. Cephalometric and digital smile planning can give an estimate of the likely profile change before treatment starts. It is important to have realistic expectations and ensure you are happy with the projected outcome.

Is bimaxillary proclination available on the NHS?

NHS treatment is available to eligible patients under 18 where the IOTN score meets grade 4 or 5. Significant incisor proclination contributing to overjet, lip incompetence, or traumatic overbite can achieve these scores. Adults are not eligible for NHS orthodontics except in exceptional clinical circumstances. If you are unsure, ask your GDP to complete an IOTN assessment and refer you if appropriate.

Is bimaxillary proclination more common in some populations?

Yes, and this matters for how it is judged. Forward-inclined upper and lower incisors are considerably more common in people of African and East Asian heritage, and in those groups a degree of proclination is a normal variation rather than a deviation to be corrected. The cephalometric norms most widely used in UK practice were derived largely from white European populations, so applying them without adjustment can label a normal facial pattern as a problem. A good assessment weighs the patient's own facial proportions and what they want changed, not a single reference number.

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Citation details

Title Bimaxillary Proclination UK | Treatment & Outcomes (2026)

Publisher Virtual Consultant Online

Published 2024-06-01

Updated 2026-08-17

URL [https://staging.virtualconsultant.online/guides/bimaxillary-proclination-treatment-uk](https://staging.virtualconsultant.online/guides/bimaxillary-proclination-treatment-uk)