Maxillofacial Surgery: Orthognathic, Preprosthetic, and Reconstructive Procedures
Orthognathic Surgery · TMJ Surgery · Cysts & Tumours · Preprosthetic Surgery · Salivary Gland Surgery
TL;DR
Oral and maxillofacial surgery (OMFS) is the specialty dealing with surgical and related treatment of diseases, injuries, and defects involving the functional and aesthetic aspects of the hard and soft tissues of the oral and maxillofacial region. For board examinations, the key OMFS topics beyond exodontia and basic surgery are: orthognathic surgery procedures and their indications; odontogenic cysts and tumours (classification, radiographic features, treatment); TMJ surgical procedures; preprosthetic surgical techniques; and salivary gland pathology and surgery.
- Orthognathic surgery corrects skeletal discrepancies of the jaws that cannot be addressed by orthodontics alone — the Le Fort I osteotomy is the standard procedure for repositioning the maxilla: Orthognathic surgery (from Greek: orthos = straight; gnathos = jaw) involves surgical repositioning of the jaws to correct skeletal malocclusion, facial imbalance, and associated functional problems (obstructive sleep apnoea, TMD, difficulty chewing). The Le Fort I osteotomy is a horizontal cut through the maxilla above the root apices and below the zygomatic buttress, allowing the maxilla to be mobilised as a free segment — it can then be moved anteriorly (to correct maxillary hypoplasia, as in Class III), posteriorly (Class II), superiorly (to reduce vertical height of the lower face — “impaction”), inferiorly (to increase lower face height), or rotated. The Le Fort I is the single most commonly performed orthognathic procedure. Le Fort II and III osteotomies involve progressively higher cuts through the face — Le Fort II is a pyramidal osteotomy through the nasomaxillary complex; Le Fort III involves complete craniofacial disjunction (separating the entire midface from the cranium) — both are primarily used for craniofacial dysmorphology (Crouzon syndrome, Apert syndrome) rather than routine orthognathic treatment. The Bilateral Sagittal Split Osteotomy (BSSO) is the standard procedure for repositioning the mandible — it splits the ramus in the sagittal plane, allowing the tooth-bearing segment to be moved forward (most common — mandibular advancement for Class II) or backward (setback for Class III). Inferior alveolar nerve injury is the principal complication — temporary paraesthesia in ~50–70% of patients; permanent in ~5–10%.
- The dentigerous cyst is the most common developmental odontogenic cyst; the radicular (periapical) cyst is the most common odontogenic cyst overall: Odontogenic cysts arise from epithelial remnants of the tooth-forming apparatus — enamel organ (Hertwig’s epithelial root sheath, Malassez rests, dental lamina, reduced enamel epithelium). Classification: Developmental (not associated with inflammation): dentigerous (follicular) cyst — most common developmental; surrounds the crown of an unerupted tooth (enlarged dental follicle >5mm); treated by enucleation ± marsupialization. Odontogenic keratocyst (OKC/KCOT — keratocystic odontogenic tumour in the 2005 WHO classification — reclassified as cyst in 2017 WHO): unique features — parakeratinised stratified squamous epithelium; Daughter cysts (satellite cysts) in the wall; high recurrence rate (25–60%) due to daughter cysts; associated with Gorlin-Goltz (naevoid basal cell carcinoma) syndrome (multiple OKCs + calcified falx cerebri + rib anomalies + basal cell naevi). Treatment: enucleation + Carnoy’s solution chemical fixation of cyst wall or peripheral ostectomy to reduce recurrence. Inflammatory (associated with inflammation, non-vital tooth): radicular (periapical) cyst — most common odontogenic cyst overall (55–70% of all jaw cysts); lined by non-keratinised stratified squamous epithelium from Malassez rests; associated with non-vital tooth; treatment: root canal treatment (resolves most cysts <10mm) or periapical surgery (apicoectomy + retrograde filling) for persistent/large lesions. Residual cyst: a radicular cyst that remains after tooth extraction. Lateral periodontal cyst: rare developmental cyst adjacent to the lateral root surface — most commonly mandibular premolar/canine region.
- The ameloblastoma is the most clinically significant (most aggressive) odontogenic tumour and carries the highest recurrence rate if not radically treated: The ameloblastoma arises from the enamel organ or its remnants and is the second most common odontogenic tumour (after odontoma). It is a locally aggressive, slow-growing, benign (but locally malignant in behaviour) tumour — it does not metastasize. Radiographic appearance: “soap bubble” or “honeycomb” (multilocular) radiolucency in 75–80% of cases; can be unilocular (particularly in young patients — unicystic ameloblastoma). Location: posterior mandible (most common — mandibular molars/ramus region) in ~75% of cases. Microscopic types: follicular (most common), plexiform, acanthomatous, granular cell, desmoplastic. Unicystic ameloblastoma: occurs in a younger age group (10–30 years); associated with unerupted lower third molar; better prognosis; may be treated by enucleation + curettage vs. resection depending on the intramural extension. Solid/multicystic ameloblastoma: high recurrence (50–90%) if treated by enucleation alone — requires resection with adequate margins (at least 1–1.5cm of apparently normal bone beyond the radiographic margin). Ameloblastic carcinoma: rare malignant variant; metastasises.
- The submandibular gland is the most common site of salivary calculi (sialolithiasis), and the management has evolved from open surgery to minimally invasive sialendoscopy: Sialolithiasis affects the submandibular gland in 80–90% of cases (Wharton’s duct — long, against gravity, viscous calcium-rich saliva). Presentation: meal-related pain and swelling of the gland (salivary colic) — maximal at mealtimes when salivary flow is stimulated and blocked by the stone. On examination: palpable stone in the floor of the mouth on bimanual palpation (one finger intraoral, one extraoral); the duct may appear inflamed. Imaging: occlusal radiograph (confirms calcified stone in the floor of the mouth); ultrasound (non-calcified or parotid stones); CT (stone location and size). Treatment: stones in the anterior duct (at or anterior to the first molar) are accessible intraorally — milking the gland, probing and dilating the duct os, or intraoral incision over the stone under local anaesthesia. Posterior stones and stones within the hilum of the gland require: extracorporeal shock-wave lithotripsy (ESWL — for stones <7mm); sialendoscopy (endoscopic basket retrieval through the duct os — minimally invasive, gland-preserving); or formal submandibular gland excision (for recurrent stones, recurrent infections, or gland damage). Risk of lingual nerve and hypoglossal nerve injury during submandibular gland excision is the primary concern — careful dissection deep to the posterior belly of the digastric and identification of the lingual nerve in the submandibular triangle is required.
- Orthognathic surgery requires combined orthodontic-surgical treatment planning — the surgical and orthodontic team must plan together before initiating treatment: Orthognathic surgical outcomes depend on pre-surgical dental decompensation — the teeth must be orthodontically positioned on their respective jaw bases in preparation for surgery, as if the surgery had already been performed. This “decompensation” phase typically takes 12–18 months of pre-surgical orthodontics and worsens the patient’s appearance and malocclusion before surgery. Surgery-first approaches have been developed more recently (particularly for Class III cases with minimal dental compensation), allowing surgery first followed by post-surgical orthodontics — this reduces total treatment time but requires careful patient selection and surgical precision. Post-surgical orthodontics for 6–12 months finalises tooth position and occlusal refinement. Virtual surgical planning (VSP) using CBCT + digital model integration has become the standard for complex orthognathic cases — it allows precise simulation of planned osteotomies and movements, custom cutting guides, and custom titanium plates for highly accurate and reproducible results.
Key Facts
What Is Maxillofacial Surgery?
Oral and maxillofacial surgery is the surgical specialty concerned with the diagnosis and treatment of diseases, injuries, and structural and aesthetic defects of the face, jaws, and related structures. It bridges dentistry and medicine — the OMFS specialist holds qualifications in both dentistry and medicine in many countries (dual-qualified surgeon). Core competency areas include: dentoalveolar surgery (exodontia, impacted teeth); orthognathic and craniofacial surgery; head and neck oncology; reconstructive surgery (free flap reconstruction after cancer resection); oral pathology and biopsy; facial trauma (fracture management); TMJ surgery; cleft palate and craniofacial deformity surgery; salivary gland disease; and implant surgery. The general dentist must understand OMFS principles to: recognise conditions requiring specialist referral; co-manage patients before and after OMFS procedures; understand the complications and post-operative course; and explain procedures to patients seeking information.
Why It Matters
Board examinations test OMFS through clinical scenarios: a patient has jaw disharmony — what surgery corrects Class III? A radiograph shows a multilocular radiolucency — what is the most likely diagnosis and what are the recurrence risks? A cyst is found on a panoramic radiograph — is it radicular, dentigerous, or OKC, and how is each treated? What nerve is at risk during submandibular gland excision? These are the representative question types for the OMFS component.
Orthognathic Surgery
Le Fort Osteotomies
The Le Fort classification of facial fractures (René Le Fort, 1901) describes patterns of midfacial fracture following blunt trauma — he identified that the face tends to fracture along predictable lines of weakness. These same lines are now used by surgeons as osteotomy guides for planned surgical access to the midface. Le Fort I: horizontal osteotomy through the maxilla above the root apices (from one piriform rim to the other, through the lateral maxillary wall and pterygomaxillary junction) — separates the tooth-bearing maxillary segment from the upper face; allows three-dimensional repositioning of the maxilla. Le Fort II: pyramidal osteotomy through the nasal bones (at the nasofrontal junction), the medial orbital walls and floor, and the zygomatic arch — moves the central midface including the nose. Le Fort III: craniofacial disjunction — osteotomy at the zygomaticofrontal suture, through the orbital floor, and through the nasofrontal suture and pterygomaxillary junction — separates the entire midface from the cranial base; used for complete midface advancement in Crouzon and Apert syndromes (premature craniosynostosis).
Bilateral Sagittal Split Osteotomy (BSSO)
The BSSO (first described by Trauner and Obwegeser in 1957; modified by Dal Pont in 1961 for a more anterior split) is performed via an intraoral incision along the anterior border of the ramus. The osteotomy splits the ramus in the sagittal plane — the buccal cortex is cut from the lower sigmoid notch to the lateral border of the mandible (Dal Pont modification runs the buccal cut to the first molar area), and the medial cut is made horizontally above the lingula. The two cortical plates are separated (split) with osteotomes, separating the mandible into a proximal segment (condyle + ramus) and a distal segment (tooth-bearing portion). The distal segment can then be moved forward (advancement for Class II) or backward (setback for Class III) to achieve the planned skeletal relationship. The segments are fixed with titanium screws or plates. The IAN passes between the two cortical layers in the mandibular canal and is at risk during the split — the nerve must be identified and protected. Modifications: Inverted-L osteotomy and C-osteotomy — used for specific movement requirements or revision cases.
Genioplasty
Genioplasty (chin osteotomy) allows isolated repositioning of the chin point. An intraoral incision is made in the lower labial sulcus; the mentalis muscle is reflected; the osteotomy is made horizontally below the mental foramina; the chin segment is repositioned: advanced (most common — Class II, microgenia), set back (macrogenia), raised (vertical reduction), lowered (vertical increase), or shifted laterally (correction of asymmetry). The mental nerve exits the mental foramen bilaterally — it must be identified and protected. Genioplasty is frequently combined with BSSO and Le Fort I for comprehensive orthognathic correction of all three jaw components.
Odontogenic Cysts and Tumours
| Lesion | Classification | Epithelial Origin | Radiographic Appearance | Treatment | Recurrence Risk |
|---|---|---|---|---|---|
| Radicular (periapical) cyst | Inflammatory | Malassez rests | Well-defined radiolucency at root apex; associated non-vital tooth | RCT (small cysts); periapical surgery (large or persistent) | Low if well treated |
| Dentigerous (follicular) cyst | Developmental | Reduced enamel epithelium | Well-defined unilocular RL encircling crown of unerupted tooth; RL >5mm is suspect | Enucleation ± marsupialization for large cysts; remove associated tooth or expose and allow eruption | Low |
| OKC / KCOT | Developmental | Dental lamina remnants | Unilocular or multilocular RL; often extends along length of bone with minimal expansion; mandible posterior (common) | Enucleation + Carnoy’s solution; peripheral ostectomy; resection for recurrent cases | High (25–60%) — daughter cysts; Gorlin-Goltz association |
| Lateral periodontal cyst | Developmental | Dental lamina remnants | Well-defined RL lateral to root of vital tooth; mandibular premolar/canine region | Enucleation | Low |
| Odontoma | Developmental odontogenic tumour (hamartoma) | All odontogenic tissues | Complex (irregular mass of dental structures; no recognisable tooth form) or compound (multiple tooth-like denticles) | Enucleation (curative — no recurrence) | None |
| Ameloblastoma | Benign odontogenic epithelial tumour | Enamel organ remnants / reduced enamel epithelium | Multilocular “soap bubble” RL (75%); posterior mandible; unilocular in unicystic type | Resection with 1–1.5cm clear margins (solid type); enucleation/curettage for unicystic type (selected cases) | High (50–90%) with conservative treatment; low with adequate resection |
| Odontogenic myxoma | Benign odontogenic ectomesenchymal tumour | Dental papilla mesenchyme | “Tennis racket” (multilocular with right-angle septa) or “spider-web” pattern RL; mandible | Resection with margins (high recurrence with enucleation) | Moderate (25%) |
| Cementoblastoma | Benign odontogenic tumour | Cementoblasts | Well-defined radiopaque mass fused to root apex (mandibular first molar most common); painful; radiolucent rim around the mass | Extraction of the involved tooth + removal of the lesion (tooth-lesion unit) | Low |
TMJ Surgery
The vast majority of TMD patients are managed non-surgically (occlusal splints, physiotherapy, NSAIDs, biofeedback, cognitive behavioural therapy). Surgical TMJ procedures are reserved for patients who have failed maximal non-surgical therapy and have structural intracapsular pathology. Procedures range from minimally invasive to open surgery: Arthrocentesis: the simplest procedure — two needles are placed into the upper joint compartment (using a standard point — 10mm anterior to the tragus of the ear along the tragus-canthus line — and a second point 2mm anterior); the joint is lavaged (irrigated) with Ringer’s lactate; this washes out inflammatory mediators (cytokines, bradykinin, serotonin) from the joint space; releases adhesions; and restores movement. Indications: acute closed lock (disc displacement without reduction) refractory to conservative treatment; inflammatory arthritis; early degenerative joint disease. Success rate for pain and function improvement: 70–85%. Arthroscopy: arthroscopic examination and treatment of the upper compartment using a 1.9–2.3mm arthroscope; allows direct visualisation, lysis of adhesions, discal repositioning, and lavage under direct vision. More invasive than arthrocentesis; higher success rates for selected patients. Open joint surgery: indicated for structural pathology not amenable to arthroscopic treatment — displaced or perforated disc (disc repositioning/discoplasty or discectomy with or without alloplastic disc replacement); ankylosis (fibrous or bony — condylectomy + gap arthroplasty + free fat graft); condylar hyperplasia (condylectomy); tumour (condylectomy + total joint replacement — Biomet/Stryker custom prostheses). Total alloplastic TMJ replacement: indicated for end-stage degenerative joint disease; condylar aplasia/hypoplasia; previous failed TMJ surgery; ankylosis recurrence. The prosthesis consists of a fossa component (titanium or polyethylene, screwed to the glenoid fossa/zygomatic arch) and a condylar component (titanium alloy head + polyethylene bearing surface, screwed to the ramus). CN VII is at risk in all open TMJ procedures — the branches run immediately superficial to the joint capsule.
Preprosthetic Surgery
Preprosthetic surgery aims to create an optimal foundation for removable or fixed prosthetics. Key procedures: Alveoloplasty: surgical recontouring of irregular alveolar ridges after extraction — prominent inter-septal bone spicules, undercuts, and sharp ridges are smoothed to create a rounded, comfortable ridge form that will not cause pain under a denture. Torus removal: torus mandibularis (bilateral bony exostoses on the lingual aspect of the mandible, in the premolar region — non-pathological, developmental) and torus palatinus (midline bony exostosis on the hard palate) are removed when they interfere with denture construction or function, or when they become traumatised. Tori are dense cortical bone — require bur/chisel removal and significant soft tissue flap reflection. Soft tissue corrections: high frenal attachments (labial frenulum attached close to the crest — pulls the denture off; corrected by frenectomy or frenuloplasty); muscle attachments close to the crest; redundant tissue rolls (epulis fissuratum — hyperplastic fibrous tissue reaction to denture flanges); flabby ridge (replacement of bone by fibrous tissue in the anterior maxilla — typically in longstanding edentulous patients wearing upper dentures; requires fibrous tissue excision and bony ridge recontouring). Vestibuloplasty: deepening of the buccal or lingual vestibule to improve denture stability and retention — involves relocating the muscle attachments inferiorly/superiorly relative to the alveolar crest.
Salivary Gland Surgery
Parotidectomy: surgical removal of all or part of the parotid gland, most commonly for pleomorphic adenoma (benign mixed tumour — most common salivary gland tumour — encapsulated but pseudopod extensions mean simple enucleation has high recurrence; requires superficial parotidectomy with clear margins). The facial nerve (CN VII) is the critical structure — it exits the stylomastoid foramen, enters the posterior surface of the parotid, and divides into the five terminal branches within the parotid substance. The nerve is identified at the stylomastoid foramen (using surgical landmarks: the tragal pointer, the posterior belly of the digastric, the tympanomastoid fissure) and traced forward through the gland to protect all branches. Temporary facial weakness occurs in up to 30–40% of patients post-parotidectomy; permanent weakness in ~1–5% for superficial parotidectomy. Frey’s syndrome (auriculotemporal syndrome): aberrant reinnervation of the sweat glands of the preauricular skin by parasympathetic fibres from the auriculotemporal nerve (damaged during surgery) → sweating and flushing of the preauricular skin in response to salivary stimulation (eating); occurs in ~30–50% of parotidectomy patients; managed with topical anticholinergics (glycopyrrolate cream) or botulinum toxin injection. Submandibular gland excision: indicated for recurrent sialolithiasis (posterior stones, multiple stones, gland damage from recurrent infections) or submandibular salivary gland neoplasm. Nerves at risk: lingual nerve (CN V3 branch — lies on the deep surface of the gland — injury causes ipsilateral tongue anaesthesia and taste loss); hypoglossal nerve (CN XII — lies inferiorly — injury causes tongue deviation); marginal mandibular branch of CN VII (lies superficial, along inferior border of mandible — injury causes lower lip asymmetry).
Other Pathological Conditions in OMFS
Gorlin-Goltz syndrome (naevoid basal cell carcinoma syndrome): autosomal dominant; mutation in PTCH1 (patched 1) tumour suppressor gene. Features: multiple OKCs of the jaws (bilateral, recurrent from childhood); multiple basal cell carcinomas of the skin (appear in early adulthood); calcification of the falx cerebri on skull X-ray (pathognomonic); bifid ribs; frontal bossing; other skeletal anomalies; medulloblastoma risk. Any patient with multiple jaw cysts must be evaluated for Gorlin-Goltz syndrome. Cherubism: autosomal dominant fibrous dysplasia-like condition; SH3BP2 gene mutation; bilateral posterior mandibular expansion in children; radiographic appearance: bilateral multilocular radiolucencies of the mandible (and sometimes maxilla); spontaneous regression at puberty in most cases; named for the characteristic round-cheeked appearance. MRONJ (medication-related osteonecrosis of the jaw): area of exposed, necrotic bone in the oral cavity, present for >8 weeks, in a patient exposed to anti-resorptive (bisphosphonate, denosumab) or anti-angiogenic therapy, with no history of radiation to the jaw. The jaw is uniquely vulnerable. Staging (AAOMS 2014): Stage 0 (symptoms only, no exposed bone); Stage 1 (exposed bone, no symptoms, no infection); Stage 2 (exposed bone + pain + infection); Stage 3 (exposed bone + pathological fracture or orocutaneous fistula or osteolysis to inferior border/zygoma). Treatment escalates from conservative (CHX rinse, analgesics, avoid surgery) through stage-appropriate surgery to resection for Stage 3.
Clinical Considerations
- Not all multilocular jaw radiolucencies are ameloblastomas — the differential diagnosis is broad and biopsy is mandatory before treatment: A multilocular jaw radiolucency may represent: ameloblastoma (soap bubble pattern, posterior mandible); OKC (minimal expansion, runs along the length of the bone); odontogenic myxoma (tennis racket pattern); central giant cell granuloma (anterior mandible, crosses midline); cherubism (bilateral, posterior mandible, children); aneurysmal bone cyst; Burkitt’s lymphoma (in children in endemic malaria regions); metastatic carcinoma. Biopsy (incisional biopsy of representative tissue from the lesion wall) is mandatory before any definitive surgical treatment — the treatment for each entity is different and treating an ameloblastoma as if it were an OKC (with Carnoy’s solution and enucleation) will result in early recurrence.
- The odontogenic keratocyst must always be considered when a cyst is in the mandibular third molar/ramus region — its recurrence rate and syndrome association distinguish it from other cysts: OKC is clinically deceptive — it tends to grow along the medullary space of the mandible with minimal cortical expansion, making it larger on radiograph than it clinically appears. This growth pattern means it often involves the ramus extensively by the time of diagnosis. The high recurrence rate (25–60%) is due to the satellite (daughter) cysts and cell rests in the cyst wall that are not completely removed by simple enucleation. Additional measures — Carnoy’s solution application (fixes residual epithelium chemically), peripheral ostectomy (removes 1–2mm of peripheral bone), or marsupialization (converts to less aggressive OKC — reduces size before enucleation) — are used to reduce recurrence. Always consider Gorlin-Goltz syndrome in patients with OKC, particularly if: <20 years of age; multiple cysts; recurrent cysts; family history.
- Pre-surgical orthodontic decompensation is essential for predictable orthognathic outcomes and must not be skipped: In Class III patients, the upper teeth are proclined and lower teeth are retroclined (dental compensation for the skeletal discrepancy — the teeth have “compensated” to maintain some degree of occlusal contact). If surgery is performed without orthodontic decompensation, the dental compensation will prevent full skeletal movement — the surgeon cannot achieve the planned skeletal change because the teeth are in the way. Decompensation involves: uprighting the upper incisors (reducing their proclination) and flaring the lower incisors (removing their retroclination) so that after surgery, the skeletal change can be maximised and the incisors will be in the correct angulation relative to their jaw bases. This process makes the patient look and feel worse during treatment — this is expected and must be explained and consented for at the outset.
- The buccal fat pad is a versatile local flap for closing oro-antral communications and intraoral defects in the posterior maxilla: The buccal fat pad (Bichat’s fat pad) lies in the buccal space between the buccinator and masseter muscles. It has a central body and four extensions (buccal, pterygoid, superficial temporal, deep temporal). The buccal extension lies adjacent to the posterior maxillary buccal mucosa and can be accessed through a small incision in the upper buccal vestibule above the second molar. When gently pulled through the incision, the fat pad can be spread over a defect as a pedicled graft and then sutured to the defect margins — it rapidly epithelialises from the surrounding mucosa. The buccal fat pad flap is used for: oro-antral fistula closure (failure of primary closure); closure of small defects after maxillary cyst or tumour removal; as a lining graft for sinus lift lateral windows. It is a robust, reliable, and quickly executed technique particularly suited to the posterior maxilla where other local flaps have limited reach.
- The pleomorphic adenoma is the most common salivary gland tumour and must be removed with a margin of normal tissue — enucleation alone causes recurrence: Pleomorphic adenoma (benign mixed tumour) accounts for ~65–75% of all salivary gland tumours — most commonly in the parotid gland (80%). It is a benign tumour with a fibrous pseudocapsule that has pseudopod extensions penetrating through the capsule — these pseudopods are left behind if simple enucleation is performed, causing recurrence. The appropriate operation is superficial parotidectomy (preserving CN VII) with the tumour included in the specimen with a rim of normal parotid tissue. If a pleomorphic adenoma recurs, it becomes multinodular and recurrence surgery carries a much higher rate of facial nerve injury. Rare malignant transformation (carcinoma ex pleomorphic adenoma) occurs in approximately 6% of untreated lesions over 10+ years — another reason for prompt surgical management.
Common Mistakes & Misconceptions
- Misconception: “The Le Fort I osteotomy can only move the maxilla anteriorly.”
Correction: The Le Fort I osteotomy frees the maxilla as a completely mobile segment that can be repositioned in any direction: anteriorly (most common — correction of maxillary hypoplasia, Class III), posteriorly (unusual — to correct maxillary hyperplasia contributing to Class II), superiorly (impaction — to reduce vertical lower face height, correct gummy smile), inferiorly (downgraft — to increase lower face height), asymmetrically (one side up, one side down — to correct facial asymmetry), and rotated in the axial plane. This three-dimensional freedom of movement is the fundamental advantage of the Le Fort I over simple orthodontic treatment. - Misconception: “Ameloblastoma and OKC can be treated the same way.”
Correction: These are fundamentally different lesions requiring different surgical approaches. OKC has a high recurrence rate but is a cyst — the primary treatment is careful enucleation with chemical fixation (Carnoy’s solution) of the residual epithelium in the bone; resection is reserved for multiply-recurrent cases. The solid/multicystic ameloblastoma is a locally aggressive tumour — enucleation alone results in 50–90% recurrence because tumour islands infiltrate the cancellous bone spaces well beyond the visible radiographic margin; it requires resection with a 1–1.5cm bone margin beyond the radiographic edge. Treating ameloblastoma with conservative enucleation (appropriate for OKC) will inevitably result in early, aggressive recurrence. - Misconception: “Gorlin-Goltz syndrome is associated with ameloblastomas.”
Correction: Gorlin-Goltz syndrome (naevoid basal cell carcinoma syndrome) is associated with odontogenic keratocysts (OKCs), not ameloblastomas. The association is important because multiple OKCs in a young patient should trigger screening for the syndrome. The features of Gorlin-Goltz are: multiple OKCs; multiple basal cell carcinomas (appear in the second–third decade); calcification of the falx cerebri (visible on skull PA radiograph); bifid ribs; frontal bossing; and medulloblastoma risk. The PTCH1 gene mutation also predisposes to other tumours. Ameloblastoma has no consistent genetic syndrome association. - Misconception: “Torus palatinus requires removal in all cases.”
Correction: Torus palatinus is a non-pathological developmental bony exostosis and requires removal only when it causes specific problems: it interferes with denture construction (prevents a well-fitting palatal plate); it is ulcerated or traumatised by food (sharp tori); or it causes speech problems. Many patients with torus palatinus require no treatment — the torus is simply monitored. A patient who is not planning dentures and has no symptoms has no indication for torus removal. Removing a torus unnecessarily exposes the patient to the risks of palatal flap surgery (numbness of the palate from greater palatine nerve trauma, flap dehiscence, prolonged healing of the thin palatal mucosa). - Misconception: “Frey’s syndrome is a taste disturbance after parotidectomy.”
Correction: Frey’s syndrome is a sweating and flushing response — not a taste disturbance — that occurs in the preauricular and temporal skin following parotidectomy. It is caused by aberrant reinnervation: the auriculotemporal nerve (which normally carries parasympathetic fibres to the parotid gland) is disrupted during surgery; the parasympathetic fibres regenerate but innervate the local sweat glands (rather than the absent parotid) — so gustatory stimulation (eating) causes sweating of the skin rather than salivation. It is managed with topical glycopyrrolate (anticholinergic cream) or botulinum toxin injection. Taste disturbance after parotidectomy would be related to chorda tympani injury (but the chorda tympani does not traverse the parotid gland — it passes through the infratemporal fossa — so routine parotidectomy does not typically affect taste).
Related Topics
References & Sources
- Proffit WR, White RP, Sarver DM (2003). Contemporary Treatment of Dentofacial Deformity. Mosby. [Standard orthognathic surgery text — cephalometric analysis, treatment planning, osteotomy techniques]
- El-Hakim IE, Eid MA (2002). Incidence of lingual nerve disturbance following surgical removal of lower third molar and its management. Oral Surgery, Oral Medicine, Oral Pathology. [Nerve injury incidence in OMFS — BSSO and third molar surgery]
- Barnes L, Eveson JW, Reichart P, Sidransky D (eds) (2005). World Health Organization Classification of Tumours: Pathology and Genetics of Head and Neck Tumours. IARC. [WHO 2005 classification — odontogenic cysts and tumours including OKC as KCOT]
- El-Naggar AK, Chan JKC, Grandis JR, et al. (eds) (2017). WHO Classification of Head and Neck Tumours, 4th ed. IARC. [WHO 2017 reclassification — OKC returned to cyst status; odontogenic tumour classification]
- Carlson ER, Marx RE (2014). The bicortical screws for stabilization of sagittal split osteotomies. Oral and Maxillofacial Surgery Clinics of North America. [BSSO technique and fixation]
- Kalavrezos N, Scully C (2015). Mouth cancer for clinicians. Dental Update. [Oral cancer — recognition, referral, treatment overview for general dentists]
- Iro H, Zenk J, Escudier MP, et al. (2009). Outcome of minimally invasive management of salivary calculi in 4,691 patients. Laryngoscope, 119(2):263–268. [Sialendoscopy outcomes — largest series to date]
- Ruggiero SL, Dodson TB, Fantasia J, et al. (2014). AAOMS Position Paper on MRONJ — 2014 Update. Journal of Oral and Maxillofacial Surgery, 72(10):1938–1956.
Summary
Maxillofacial surgery encompasses orthognathic surgery, odontogenic cyst and tumour management, TMJ surgery, preprosthetic surgery, and salivary gland surgery. Le Fort I osteotomy repositions the maxilla in three dimensions (most commonly for Class III skeletal correction); BSSO repositions the mandible (advancement for Class II; setback for Class III) with IAN injury risk of 50–70% temporary/5–10% permanent. The most common odontogenic cyst is the radicular (periapical) cyst; the most common developmental cyst is the dentigerous cyst; the highest-recurrence cyst is the OKC/KCOT (25–60% — daughter cysts; Gorlin-Goltz syndrome association). The ameloblastoma is the most clinically aggressive odontogenic tumour — requiring resection with 1–1.5cm margins for the solid type (50–90% recurrence with conservative treatment). Parotidectomy risks CN VII (facial nerve) injury and Frey’s syndrome; submandibular gland excision risks lingual nerve, hypoglossal nerve, and marginal mandibular nerve injury.
Key Takeaways
- Orthognathic: Le Fort I = maxillary repositioning (Class III correction = advancement; Class II = impaction/posterior). BSSO = mandibular repositioning (Class II = advancement; Class III = setback). IAN injury 50–70% temporary; 5–10% permanent. Pre-surgical orthodontics 12–18 months.
- Cysts: Most common overall: radicular (55–70%). Most common developmental: dentigerous (follicular). Highest recurrence: OKC (25–60%) → Gorlin-Goltz syndrome. OKC features: parakeratinised; daughter cysts; Carnoy’s solution or peripheral ostectomy to reduce recurrence.
- Ameloblastoma: 2nd most common odontogenic tumour. Locally aggressive, benign. Posterior mandible 75%. “Soap bubble” multilocular RL. Solid type: resection with 1–1.5cm margins. Unicystic type: younger patients; better prognosis.
- Salivary glands: Parotidectomy → CN VII risk + Frey’s syndrome (sweating, not taste loss). Submandibulectomy → lingual nerve (taste + sensation) + hypoglossal nerve (tongue deviation) risk. Pleomorphic adenoma: most common tumour (65–75%); superficial parotidectomy required (not enucleation — pseudopods).
- Gorlin-Goltz: Multiple OKCs (NOT ameloblastomas) + basal cell carcinomas + calcified falx cerebri + bifid ribs. PTCH1 gene. Medulloblastoma risk.
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