Sometimes, jaw misalignment does not come from one jaw alone. The upper jaw may be positioned too far forward or backward while the lower jaw is also misaligned, or both jaws may have developed differently in size, position, or proportion. When correcting only one jaw would not adequately address the underlying problem, double jaw surgery may be considered.
Also called bimaxillary orthognathic surgery, double jaw surgery involves repositioning both the upper jaw and lower jaw to establish a more appropriate relationship between the facial skeleton and the teeth. It is usually planned as part of a coordinated orthodontic and surgical treatment process. You can learn more about the broader treatment options on our jaw surgery page.
What Is Double Jaw Surgery?
Double jaw surgery is an orthognathic procedure in which both the maxilla (upper jaw) and mandible (lower jaw) are surgically repositioned.
The purpose is not simply to move both jaws because the bite looks unusual. The procedure is considered when the skeletal relationship between the upper and lower jaws is sufficiently complex that correcting one jaw alone would not provide the desired functional and skeletal result.
The two jaws can be moved in different directions and by different amounts. Depending on the patient's anatomy, the surgical plan may involve advancing, moving backward, rotating, widening, or repositioning one or both jaws in three dimensions.
Why Would Both Jaws Need to Be Corrected?
A bite problem can sometimes appear to come primarily from one jaw even though both contribute to the underlying discrepancy. For example, a person with a significant underbite may have:
- An excessively prominent lower jaw
- An underdeveloped or retruded upper jaw
- A combination of upper- and lower-jaw discrepancies
Similarly, a severe overbite may involve the position of the lower jaw, the upper jaw, or both. If only one jaw is moved when both contribute substantially to the problem, the surgical correction may not adequately address the overall skeletal relationship. Double jaw surgery allows the treatment team to distribute the required correction between the two jaws when that is appropriate.
What Problems Can Double Jaw Surgery Treat?
Bimaxillary surgery may be considered for several types of significant skeletal jaw discrepancies.
Severe underbite
An underbite may result from a lower jaw that is positioned too far forward, an upper jaw that is positioned too far backward, or a combination of both. Double jaw surgery can address the contribution of both jaws when necessary.
Severe overbite
Some significant overbites are associated with an abnormal relationship between both jaws. Repositioning the upper and lower jaws can allow the surgical team to establish a more appropriate skeletal and dental relationship.
Open bite
An open bite occurs when certain upper and lower teeth do not meet when the mouth is closed. When the underlying problem has a significant skeletal component, bimaxillary surgery may form part of treatment.
Facial asymmetry
When the upper and lower jaws contribute differently to facial asymmetry, correcting both may be necessary to improve the overall skeletal relationship.
Complex vertical or transverse discrepancies
Some patients have differences in the vertical height or width of the upper and lower jaws. These discrepancies may require coordinated movement of both jaws to establish an appropriate relationship.
Double Jaw Surgery vs Single Jaw Surgery
The difference is straightforward: single-jaw surgery repositions one jaw, while double jaw surgery repositions both.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
| Feature | Single-jaw surgery | Double-jaw surgery |
|---|---|---|
| Jaws treated | Upper or lower jaw | Upper and lower jaws |
| Typical use | When the main skeletal discrepancy is predominantly in one jaw | When both jaws contribute significantly to the discrepancy |
| Planning | Focused on one jaw and its relationship with the other | Three-dimensional planning of the entire maxillomandibular relationship |
| Surgical scope | Generally more limited | More extensive because both jaws are repositioned |
| Orthodontic treatment | Commonly required | Commonly required |
How Is Double Jaw Surgery Planned?
Because both jaws are being repositioned, detailed planning is particularly important. The treatment team may assess:
- The relationship between the upper and lower teeth
- The position and size of both jaws
- Facial symmetry and proportions
- Jaw movement and function
- Dental compensation
- Three-dimensional skeletal relationships
- The desired final bite
- The amount and direction of movement required for each jaw
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
What Happens Before Double Jaw Surgery?
Most patients undergo orthodontic preparation before conventional orthognathic surgery. During this stage, braces or another orthodontic appliance may be used to align the teeth and reduce the dental compensations that developed because of the jaw discrepancy.
This preparation can sometimes make the bite appear temporarily worse. That does not necessarily mean that treatment is going in the wrong direction. The teeth may need to be positioned in a way that allows the jaws to be corrected properly during surgery.
Some carefully selected patients may undergo a surgery-first approach, in which surgery takes place before the usual period of presurgical orthodontic treatment. However, this is a specialized treatment pathway and is not suitable for every patient. Evidence reviews have found shorter overall treatment times in some surgery-first protocols, but patient selection and treatment planning remain important.
How Is Double Jaw Surgery Performed?
Double jaw surgery is performed under general anaesthesia. The surgeon accesses the upper and lower jaw through carefully planned surgical approaches, commonly using incisions inside the mouth. Controlled cuts are made in the jaw bones so that the relevant segments can be repositioned.
The upper jaw is repositioned according to the surgical plan, followed by repositioning of the lower jaw. The sequence used during surgery can vary depending on the case and the surgeon's preferred technique.
Once the jaws are placed in their planned positions, the bone segments are secured using fixation devices such as plates and screws. The incisions are then closed.
The exact surgical movements vary considerably between patients. One person may require advancement of the upper jaw and repositioning of the lower jaw, while another may require vertical or rotational movements involving both jaws.
Why Is Moving Both Jaws Sometimes More Appropriate?
When both jaws contribute to the discrepancy, distributing the correction between them can allow the surgeon to achieve the desired skeletal relationship without placing all of the movement on one jaw.
This can be particularly relevant when the treatment plan involves correcting several dimensions at once—for example, the forward-backward relationship between the jaws together with a vertical discrepancy or facial asymmetry.
The objective is to create a balanced relationship between the upper jaw, lower jaw, teeth, and surrounding facial structures rather than simply moving one jaw until the teeth appear to meet.
What Is Recovery Like After Double Jaw Surgery?
Because both jaws are treated, recovery can involve more extensive swelling and dietary restrictions than some single-jaw procedures. However, recovery varies considerably between individuals and depends on the surgical movements and overall health. During the early recovery period, you may experience:
- Facial swelling
- Bruising
- Facial tightness
- Temporary numbness or altered sensation
- Difficulty opening the mouth fully
- Changes in eating and speaking
- Fatigue during the initial recovery period
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Will I Need Braces After Double Jaw Surgery?
Often, yes. Jaw surgery changes the position of the bones, but the teeth may still require further adjustment to establish the final occlusion.
Postoperative orthodontic treatment can therefore be used to refine the bite after the jaws have healed sufficiently. The overall treatment is best understood as one coordinated process rather than as surgery followed by completely separate dental treatment.
What Are the Potential Benefits of Double Jaw Surgery?
When appropriately indicated, bimaxillary surgery can address a complex skeletal discrepancy involving both jaws. Potential treatment goals include:
- Improving the relationship between the upper and lower jaws
- Establishing a more functional bite
- Improving chewing mechanics
- Correcting significant skeletal asymmetry
- Addressing certain vertical or transverse discrepancies
- Improving facial balance as a consequence of skeletal correction
- Supporting improvements in quality of life associated with correction of the underlying deformity
What Are the Risks of Double Jaw Surgery?
Double jaw surgery is a major operation and carries risks similar to other forms of orthognathic surgery. The specific risks depend on the procedures performed and the patient's individual anatomy. Potential complications include:
- Bleeding
- Infection
- Swelling and postoperative pain
- Temporary or persistent altered sensation
- Changes in the bite during healing
- Skeletal relapse
- Temporomandibular joint symptoms in some patients
- Problems related to anaesthesia
- Need for additional orthodontic or surgical treatment in selected cases
How Stable Is Double Jaw Surgery?
Long-term stability is an important part of evaluating orthognathic surgery. Some degree of skeletal change can occur after surgery as the bones heal and the surrounding tissues adapt. Stability depends on several factors, including the type of jaw discrepancy, the direction and size of surgical movements, the surgical technique, and individual healing.
Evidence from systematic reviews suggests that stability varies according to the procedure and the type of skeletal correction. For example, studies of skeletal open-bite correction have found differences in stability between maxillary, mandibular, and bimaxillary approaches, while reviews of Class II and Class III treatment have also identified procedure-specific differences. Therefore, double jaw surgery should not be described as having one universal relapse rate or stability percentage.
Is Double Jaw Surgery More Complicated Than Single Jaw Surgery?
Because two jaws are repositioned, double jaw surgery generally involves a more extensive surgical plan than surgery involving only one jaw. However, whether it is the appropriate or necessary approach depends on the underlying skeletal problem.
The fact that two jaws are being treated does not mean that the procedure is automatically more appropriate for every complex-looking bite. If the discrepancy can be corrected adequately by operating on one jaw, a single-jaw procedure may be considered instead. The goal is to use the least extensive surgical approach that can appropriately correct the underlying skeletal problem.
Who May Need Double Jaw Surgery?
A patient may be considered for bimaxillary surgery when examination shows that both jaws contribute significantly to the skeletal discrepancy. This may include people with:
- Complex skeletal Class II or Class III relationships
- Severe facial asymmetry involving both jaws
- Significant open bite with a skeletal component
- Combined horizontal and vertical jaw discrepancies
- Complex transverse discrepancies
- Jaw relationships that cannot be corrected adequately by orthodontics or single-jaw surgery alone
The Bottom Line
Double jaw surgery is designed for situations in which both the upper and lower jaws contribute significantly to a skeletal misalignment. Rather than compensating for the problem by moving the teeth or placing all of the correction on one jaw, bimaxillary surgery allows the treatment team to reposition both jaws according to the individual's anatomy.
The procedure is carefully planned using clinical examination, orthodontic assessment, imaging, and often three-dimensional surgical planning. Orthodontic treatment commonly forms part of the process before and after surgery.
For appropriately selected patients, double jaw surgery can correct complex jaw relationships, improve the functional relationship between the teeth and jaws, and contribute to improved facial balance. Because it is a major procedure, the potential benefits, risks, recovery, and long-term stability should be evaluated as part of an individualized treatment plan.
