Skeletal vs Dental Malocclusion: What's the Difference and Why It Matters

What is dental malocclusion?

Dental malocclusion refers to a misalignment that originates in tooth position rather than jaw position. The underlying jaws are broadly normal in size and relationship, but individual teeth — or groups of teeth — are tipped, rotated, crowded, or spaced in ways that disrupt the bite. Dental malocclusions respond well to orthodontic treatment alone. Fixed braces, clear aligners, or removable appliances can move teeth into the correct positions without any need to alter the jaws themselves. The skeletal base — the foundation on which the teeth sit — is adequate, and treatment aims to make best use of the space available within it.

What is skeletal malocclusion?

Skeletal malocclusion arises when the upper jaw (maxilla) and lower jaw (mandible) differ significantly in size, position, or both. The teeth may actually be well-aligned within their own arches, but because the jaws do not relate to each other correctly, the bite is disrupted. A skeletal Class II pattern means the lower jaw sits too far back relative to the upper; a skeletal Class III pattern means the lower jaw protrudes or the upper jaw is underdeveloped. In growing patients, jaw growth can sometimes be guided to reduce the discrepancy. In adults who have finished growing, significant skeletal malocclusions often require orthognathic (jaw) surgery combined with orthodontics to achieve a stable, functional result.

Skeletal Classes I, II, and III

Orthodontists classify the underlying jaw relationship as Class I, II, or III — separate from, though related to, Angle's dental classification. Skeletal Class I indicates a normal jaw relationship; any malocclusion is predominantly dental. Skeletal Class II describes a lower jaw that is set back relative to the upper, creating a convex facial profile and often a prominent overjet. Mild skeletal Class II can be managed with camouflage orthodontics; severe cases in adults typically require surgery. Skeletal Class III describes a lower jaw that protrudes ahead of the upper or an underdeveloped upper jaw, producing a concave profile and often an anterior crossbite or underbite. Mild cases in adults can be camouflaged; moderate to severe cases usually benefit most from surgical correction. Skeletal Class III is more prevalent in East Asian populations and has a strong genetic component.

How cephalometric analysis distinguishes them

A cephalometric radiograph — a standardised side-on X-ray of the skull — allows orthodontists and oral surgeons to measure the true relationship between the jaws with precision. Key measurements include the ANB angle (the angle between two skeletal landmarks that indicates how far the upper and lower jaws are offset from each other), the SNA and SNB angles (which describe the position of the upper and lower jaws relative to the cranial base), the Wits appraisal, and the FMPA (Frankfurt–mandibular planes angle, reflecting the vertical pattern of the face). These measurements make it possible to determine whether a discrepancy is primarily dental or skeletal, how severe it is, and whether it falls within the range that orthodontics alone can manage. Soft tissue analysis assesses lip position and facial profile to guide treatment planning.

How IOTN scoring relates to skeletal severity

The Index of Orthodontic Treatment Need (IOTN) scores malocclusion severity for NHS eligibility purposes. Its Dental Health Component (DHC) grades overjet, overbite, crossbite, displacement, and eruption problems on a five-point scale. Skeletal discrepancies manifest in these measurements: a large overjet (IOTN grade 4 or 5) or a significant crossbite often reflect an underlying skeletal component. However, IOTN is not a direct measure of the skeletal base — a patient can have a mild skeletal discrepancy and still score highly on IOTN if there are additional dental problems, or vice versa. Clinicians use IOTN alongside cephalometric data and clinical examination to form a complete picture.

Dental compensation (camouflage) and its limits

Dental camouflage means using tooth movement to mask an underlying skeletal discrepancy. For example, in a mild skeletal Class II case, the upper front teeth can be retracted and the lower front teeth tipped forward to reduce the overjet, even though the jaw relationship has not changed. Similarly, in a mild skeletal Class III, the upper incisors can be proclined and the lower incisors retroclined to create a positive overjet. Camouflage is a reasonable approach when the skeletal discrepancy is mild to moderate, the patient is not willing to consider surgery, and acceptable tooth inclinations can be achieved without compromising aesthetics or long-term stability. It has limits: severe discrepancies cannot be adequately compensated, and pushing teeth to the extremes of their range increases the risk of root resorption, gingival recession, and relapse.

When camouflage reaches its limits

In general terms, a skeletal discrepancy measured at the ANB angle beyond approximately 5 to 6 degrees in either direction is likely to exceed what stable dental compensation can achieve. Similarly, a very high or very low FMPA (vertical pattern) constrains tooth movement options. Patients who have severely proclined or retroclined incisors as a starting point have less room to manoeuvre. Where camouflage would require the incisors to be moved to positions outside the alveolar bone, orthodontists should counsel patients that surgery offers a more predictable and stable outcome. In practice, the decision is made collaboratively between patient, orthodontist, and surgeon, weighing the degree of improvement achievable, the patient's priorities, and their tolerance for surgical risk.

Orthognathic surgery referral criteria

NHS England and most clinical guidelines suggest that orthognathic surgery should be considered when a significant skeletal discrepancy exists that cannot be adequately corrected by orthodontics alone, and when the malocclusion causes functional problems or significant psychosocial impact. Referral is typically to a combined orthodontic–oral and maxillofacial surgery (OMFS) clinic at a hospital trust. The patient must have completed growth — generally assessed by comparing serial cephalometric radiographs over at least 12 months showing no further change. Typical surgical candidates include adult skeletal Class III patients with an ANB angle below around minus 4 degrees, skeletal Class II patients with a significantly retruded mandible that camouflage cannot adequately address, and patients with severe vertical discrepancies (open bite or deep bite with a skeletal component) that relapse readily with orthodontics alone.

Patient implications: what the distinction means for your treatment plan

If your orthodontist identifies a predominantly dental malocclusion, orthodontics alone is likely to achieve a good outcome and treatment will typically be more straightforward. If a skeletal component is identified, the key questions are: how severe is it, are you still growing, and what are your goals? Growing patients may be offered growth modification with functional appliances. Adults with mild skeletal discrepancies may choose camouflage with the understanding that the jaw relationship will not change. Adults with significant skeletal discrepancies should have an informed conversation about the difference in outcomes between camouflage and surgical correction — including facial profile change, long-term stability, and the risks and benefits of surgery.

NHS vs private pathways for skeletal malocclusion

On the NHS, treatment for skeletal malocclusion in under-18s with sufficient IOTN scores is provided at no cost. Combined orthodontic and surgical treatment for adults is also available on the NHS where clinical criteria are met, but waiting times can be long and access is variable by region. Private patients have more immediate access to both orthodontic camouflage and surgical planning, can choose their treating team, and typically experience shorter waits. The cost of private combined orthodontic–surgical treatment is substantial, but some patients find this preferable to multi-year NHS waiting lists. Private health insurance rarely covers orthodontic treatment but may cover elements of surgical hospital care.

Useful related pages

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