How is orthognathic surgery different from orthodontics?

Orthodontics moves teeth through bone, while orthognathic surgery moves the jaw bones themselves. When the underlying skeletal discrepancy is too large for tooth movement alone to correct, the two are combined: orthodontics aligns the teeth and surgery repositions the jaws.

Why are both jaws sometimes operated on at once?

When the deformity involves disproportion of both the upper and lower jaw, or when a balanced facial result and stable occlusion cannot be achieved by moving one jaw alone, the maxilla and mandible are repositioned together in a single bimaxillary procedure.

Orthognathic Surgery

Orthognathic surgery is the surgical repositioning of the maxilla, mandible, or both to correct dentofacial deformities — discrepancies in the size, shape, or position of the jaws that cannot be resolved by orthodontics alone. It combines surgical mobilisation of skeletal segments with orthodontic alignment of the teeth, and is undertaken to restore occlusal function, airway, and facial proportion.

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Definition

Orthognathic surgery comprises the planned surgical movement of the tooth-bearing jaw segments — by osteotomy and fixation — to correct skeletal malocclusion and dentofacial deformity, performed in coordination with orthodontic treatment.

Scope

This area orients the reader to corrective jaw surgery as a subfield of oral and maxillofacial surgery. It introduces the core osteotomies (mandibular sagittal split, maxillary Le Fort I, and their combination in bimaxillary surgery), the role of orthodontic-surgical coordination, three-dimensional planning, and the appraisal of stability and complications. Detailed procedural essentials are developed in the child topics; this node is an overview, not clinical guidance.

Sub-topics

Core questions

When does a dentofacial discrepancy exceed what orthodontics alone can correct, requiring surgical jaw repositioning?
How are maxillary and mandibular movements planned and sequenced to achieve a stable, functional occlusion and balanced facial proportions?
What determines the post-surgical skeletal stability of each osteotomy, and which movements are most prone to relapse?
How are the principal complications — neurosensory disturbance, bleeding, and condylar change — anticipated and minimised?

Key concepts

Dentofacial deformity and skeletal malocclusion
Osteotomy and rigid internal fixation
Mandibular sagittal split osteotomy
Le Fort I maxillary osteotomy
Bimaxillary (two-jaw) surgery
Surgical-orthodontic coordination
Three-dimensional virtual surgical planning
Skeletal stability and relapse
Surgery-first approach

Mechanisms

The dentition is first decompensated by orthodontics so that the teeth sit correctly over their basal bone; the surgeon then divides the jaw with a planned osteotomy, moves the mobilised segment into a predetermined position, and secures it with plates and screws or, less commonly, with intermaxillary fixation. Healing proceeds by bony union across the osteotomy. Because the muscles, periosteum, and condyle adapt to the new position, the direction and magnitude of movement — together with the surgical technique and fixation — govern how stably the result is held, a relationship summarised in classic hierarchies of stability (Proffit, 1991; Naran, 2018).

Clinical relevance

Orthognathic surgery is a reference domain for understanding how skeletal jaw discrepancies are corrected and how outcomes such as occlusion, airway, and facial balance are assessed. The entries describe principles and evidence; they do not prescribe operative indications or individual treatment plans, which remain matters for a qualified surgical-orthodontic team.

Epidemiology

Dentofacial deformities severe enough to be considered for surgery affect a minority of the orthodontic population, with Class III and vertical (open-bite or long-face) discrepancies prominent among surgical cases. Large case series report that most procedures are completed without major complication, with minor and transient events — particularly neurosensory disturbance of the inferior alveolar nerve after mandibular surgery — being the most frequent (Chow, 2007).

History

Modern orthognathic surgery dates to the mid-twentieth century. Trauner and Obwegeser's 1957 description of the intraoral sagittal split ramus osteotomy made mandibular repositioning safer and more predictable, and subsequent refinement of the Le Fort I osteotomy extended controlled movement to the maxilla. The introduction of rigid internal fixation, cephalometric and later three-dimensional planning, and coordinated surgical-orthodontic protocols progressively transformed the field into the planned, two-jaw discipline summarised in current reviews (Naran, 2018).

Debates

Conventional orthodontics-first versus surgery-first protocols: The traditional sequence places lengthy pre-surgical orthodontics before the operation, whereas the surgery-first approach operates early and aligns the teeth afterwards to shorten treatment and exploit accelerated post-operative tooth movement; relative stability and indications remain under study.

Key figures

Hugo Obwegeser
William R. Proffit
Larry M. Wolford
William H. Bell

Seminal works

trauner-obwegeser-1957
naran-2018

Frequently asked questions

How is orthognathic surgery different from orthodontics?: Orthodontics moves teeth through bone, while orthognathic surgery moves the jaw bones themselves. When the underlying skeletal discrepancy is too large for tooth movement alone to correct, the two are combined: orthodontics aligns the teeth and surgery repositions the jaws.
Why are both jaws sometimes operated on at once?: When the deformity involves disproportion of both the upper and lower jaw, or when a balanced facial result and stable occlusion cannot be achieved by moving one jaw alone, the maxilla and mandible are repositioned together in a single bimaxillary procedure.