Bimaxillary orthognathic surgery — widely known as double jaw surgery or simply "bimax" — is one of the most transformative procedures in facial surgery, simultaneously repositioning both the upper jaw (maxilla) and the lower jaw (mandible) to correct skeletal bite discrepancies, improve airway function, and restore the kind of facial balance that no amount of orthodontic treatment alone can achieve.
Key takeaways
- Bimax surgery moves both jaws in a single operative session, correcting problems that originate in the skeleton rather than the teeth alone.
- Ideal candidates include people with significant malocclusion (underbite, overbite, open bite), facial asymmetry, obstructive sleep apnoea, or aesthetic profile concerns.
- Three-dimensional virtual surgical planning allows the surgical team to rehearse every millimetre of movement before you enter the operating theatre.
- Treatment spans roughly 18–24 months when orthodontic preparation and finishing are included; the surgical admission itself is typically two to three nights.
- Functional benefits — improved chewing, clearer speech, and in many cases a dramatically better airway — are at least as significant as the aesthetic changes.
What Is Bimaxillary Orthognathic Surgery?
The word orthognathic comes from the Greek for "straight jaw." When a jaw discrepancy is rooted in the bones themselves — rather than in tooth position — moving teeth with braces alone is insufficient and can even be harmful. Orthognathic surgery repositions the jaw bones so that the teeth, the joints (temporomandibular joints, or TMJs), and the soft tissues of the face all arrive at a balanced, functional relationship.
In a bimaxillary procedure, two distinct osteotomies (controlled bone cuts) are performed during the same anaesthetic:
- Le Fort I osteotomy — a horizontal cut through the maxilla just above the tooth roots, freeing the entire upper jaw so it can be moved forwards, backwards, upwards, downwards, or rotated.
- Bilateral sagittal split osteotomy (BSSO) — paired cuts through the ramus and body of the mandible on both sides, allowing the lower jaw to be advanced, set back, or rotated into its new position.
When chin position also needs correction, a genioplasty (controlled repositioning of the chin segment) is added, creating what surgeons call trimaxillary or three-piece surgery. Titanium plates and screws hold every segment securely while healing progresses.
Who Is a Candidate? Conditions Bimax Surgery Corrects
Skeletal malocclusion
Malocclusion is classified by the relationship of the upper and lower first molars and the incisors. Class II skeletal patterns — a retruded lower jaw relative to the upper — produce the classic "weak chin" profile and a deep overbite. Class III patterns — an underbite where the lower jaw protrudes ahead of the upper — are among the most common indications for bimax surgery, particularly in East Asian populations where the prevalence is higher. Anterior open bite, where the back teeth touch but the front teeth do not meet at all, is another frequent indication; it is often associated with a steep jaw angle and can be highly resistant to orthodontic treatment alone.
Facial asymmetry
When one side of the face has grown differently from the other — a condition called hemifacial microsomia at its most severe, but more often a subtler developmental asymmetry — a single-jaw procedure usually cannot achieve symmetry. Bimax surgery, combined with 3D planning, allows the surgeon to correct cant (tilt) of the occlusal plane as well as anterior-posterior and vertical discrepancies simultaneously.
Obstructive sleep apnoea and airway
Maxillomandibular advancement (MMA) — essentially a bimax procedure performed with the specific goal of enlarging the upper airway — is recognised in the sleep medicine literature as one of the most effective surgical treatments for moderate-to-severe obstructive sleep apnoea (OSA), with success rates exceeding those of many other interventions in appropriately selected patients. By advancing both jaws, the attached soft tissues of the tongue base, soft palate, and lateral pharyngeal walls are pulled forward, expanding the retropalatal and retroglossal airway. Patients who have failed CPAP or who want a definitive structural solution are increasingly seeking this route.
Facial aesthetics, feminisation, and masculinisation
Skeletal jaw position is a powerful determinant of facial profile. A well-executed bimax procedure can sharpen a soft profile, reduce facial height, or open up a compressed mid-face — outcomes that have relevance not only in conventional aesthetic surgery but also in facial gender-affirming surgery. In feminisation contexts, reducing a prominent mandible while refining the chin with genioplasty can soften the lower third considerably. In masculinisation, advancing a retrognathic mandible and squaring the chin through a simultaneous genioplasty contributes meaningfully to a stronger, more defined facial structure.
The Role of 3D Virtual Surgical Planning
Modern orthognathic surgery is inseparable from digital planning. A high-resolution CT scan of the skull is merged with a digital dental scan and, in some workflows, a facial photograph to create a complete three-dimensional model of the patient's anatomy. The surgical team then performs the entire operation virtually — testing different jaw movements, assessing the resulting occlusion, predicting soft-tissue changes, and confirming that no critical anatomical structures (dental roots, the inferior alveolar nerve, the maxillary sinuses) are at risk.
From this virtual plan, custom surgical splints (wafers) are milled or 3D-printed. These wafers are placed between the teeth intraoperatively to guide the jaws into their planned new positions with sub-millimetre accuracy. Custom titanium cutting guides and plates can also be pre-bent or designed to exact specifications. The result is a dramatic reduction in operative time and a much tighter match between the planned outcome and what is actually achieved on the table.
At Dr. Cömert's Istanbul practice, 3D virtual surgical planning is a standard part of every orthognathic workup, with cases reviewed jointly by the surgical and orthodontic teams before any treatment begins.
The Orthodontic–Surgical Sequence
Pre-surgical orthodontics (6–18 months)
This phase is counterintuitive for many patients: before surgery, the orthodontist deliberately decompensates the teeth — removing the adaptations the teeth have made to the underlying skeletal problem. In a Class III patient, for example, the upper incisors may have tipped forwards and the lower incisors tipped backwards over years of function; decompensation reverses this, which temporarily makes the bite look worse. The goal is to position the teeth ideally over their respective jaw bones so that, once the bones move, a correct occlusion is achieved. Arches are also levelled and coordinated so the upper and lower dental arches match each other in width and curvature.
Surgery
Once the orthodontist confirms the teeth are ready — confirmed on updated models and the virtual plan — surgery is scheduled. The procedure is performed under general anaesthesia and typically takes two to four hours for a standard bimax, slightly longer when genioplasty is included. All incisions are made inside the mouth; there are no external facial scars.
Post-surgical orthodontics (3–6 months)
After an initial healing period, the orthodontist fine-tunes the bite — closing small residual spaces, detailing individual tooth positions, and ensuring long-term stability. Braces or aligners are then removed and retainers are fitted.
The surgery-first approach
In select patients — typically younger individuals with good dental health and minimal decompensation needed — surgery can be performed first and orthodontic finishing done afterwards. This shortens the total treatment timeline substantially but requires careful case selection and close collaboration between surgeon and orthodontist.
Surgery and Hospital Stay: What to Expect
You will be admitted on the day of surgery. General anaesthesia is administered through a nasal tube (nasotracheal intubation) to keep the oral field clear. The surgeon makes incisions in the gum tissue, elevates the soft tissues from the bone, performs the planned osteotomies with precision instruments, and positions each segment according to the digital plan. The segments are fixed with small titanium plates and self-tapping screws that remain in place permanently unless they ever cause symptoms.
At the end of the procedure, the jaws are brought into occlusion and held with small rubber bands called elastics (or, less commonly today, wire maxillomandibular fixation — MMF) to guide healing. Most contemporary surgeons use light guiding elastics rather than rigid wire fixation, which greatly improves early comfort and nutrition. You will typically spend one night in intensive monitoring and one to two further nights on the ward before discharge.
Recovery: A Week-by-Week Guide
Week 1: Significant facial swelling, bruising, and a feeling of jaw tightness. Pain is managed with intravenous and then oral medication. Diet is liquid only — think smoothies, broths, and protein shakes through a syringe or soft-tip bottle. Nasal breathing may feel congested due to intraoperative fluid shifts. Numbness of the lower lip and chin is expected and relates to proximity of the inferior alveolar nerve; this almost always resolves.
Weeks 2–3: Swelling begins to subside. Most patients feel well enough to return to desk work or studies. Diet advances to soft, easily mashed foods. Elastics are still in place at night and sometimes during the day.
Week 4–6: The majority of swelling has resolved, though subtle puffiness continues. Most patients report their facial shape feels recognisably different — and better — by six weeks. Strenuous exercise and contact sports are still prohibited.
Months 3–6: Fine swelling continues to dissipate. The orthodontist resumes active treatment. Most patients return fully to normal activities including exercise by three months.
Months 6–12: Final soft-tissue settling. The refined result — including how the lips, cheeks, and chin drape over the repositioned skeleton — becomes apparent. Some patients notice the full aesthetic outcome only at the one-year mark.
Benefits: Function, Aesthetics, and Airway
The measurable functional gains from bimax surgery are well documented: improved maximum bite force, more comfortable and efficient chewing, clearer articulation of sounds that depend on lip-tooth or tongue-tooth contact, and — in MMA cases — objective reductions in apnoea-hypopnoea index (AHI) scores. The aesthetic improvements follow directly from skeletal repositioning: a more balanced facial profile, improved lip posture (lips that meet comfortably at rest rather than straining to close), and a better-defined chin-throat angle. These are skeletal, not superficial, changes — they do not fade over time in the way that soft-tissue-only procedures can.
Risks, Realistic Expectations, and Choosing Your Surgeon
No surgical procedure is without risk. For bimax surgery, the most discussed include: temporary or (rarely) permanent altered sensation in the lower lip and chin from the inferior alveolar nerve; relapse of jaw position (reduced substantially by rigid fixation and post-surgical orthodontic finishing); TMJ symptoms; infection; and the rare possibility of unfavourable bone healing. Airway management in the early post-operative period requires experienced anaesthetic and nursing teams, particularly in patients with pre-existing OSA.
Choosing a surgeon with specific, high-volume orthognathic experience — and who works in close partnership with a qualified orthodontist from the outset — is the single most important decision you will make. Ask to see the surgical team's virtual planning workflow, their before-and-after cases, and their protocol for managing complications. Istanbul has emerged as a significant destination for international orthognathic patients seeking experienced surgeons, competitive pricing relative to Western Europe and North America, and short waiting lists. Dr. Cömert's team coordinates international patient logistics from initial digital consultation through to discharge planning and post-operative follow-up.