Dentistry

Mandible Fracture PDF

Mandible Fracture

Mandible is embryologically a membrane bent bone although, resembles physically long bone it has two articular cartilages with two nutrient arteries.

Mandible in trauma

Mandibular fracture is more common than middle third fracture (anatomical factor)
It could be observed either alone or in combination with other facial fractures
Minor mandibular fracture may be associated with head injury owing to the cranio-mandibular articulation
Mandibular fracture may compromise the patency of the airway in particular with loss of consciousness
Fracture of mandible occurred with frontal impact force as low as 425 lb (190 Kg) {Condylar fracture}
Fracture of condyle regarded as a safety mechanism to the patient
Frontal force of 800-900 lb (350-400 Kg) is required to cause symphesial fracture
Mandible was more sensitive to lateral impact than frontal one
Frontal impact is substantially cushioned by opening and retrusion of the jaw
(Nahum 1975)
Long canine tooth and partially erupted wisdoms represent line of relatively weakness

Mandible Fracture

Anatomical considerations

Attached muscles:
  • Masseter
  • Temporalis
  • Medial and lateral pterygoid
  • Mylohyoid
  • Geniohyoid and genioglosus
  • Anterior belly of digastrics
Blood supply
  • Endosteal supply via the ID artery and vein
  • Periosteal supply, important in aging due to diminishes and disappearance of alveolar artery
  • Bradley 1972
Nerve
  • Damage of inferior dental nerve
  • Facial palsy by direct trauma to ramus
  • Damage of facial nerve in temporal bone fracture
  • Goin 1980
  • Damage to mandibular division of facial nerve

Factors influenced site of fracture and displacement

  • Anatomy of the mandible and attached muscle (canine & wisdoms)
  • Weakening areas of mandible (resorption and pathologyl)
  • Direction of force of the blow
  • Age of the patient

Mandible Fracture

Types of fracture

  • Simple
    Greenstick fracture (rare, exclusively in children)
    Fracture with no displacement (Linear)
    Fracture with minimal displacement
  • Displaced fracture
  • Comminuted fracture
    Extensive breakage with possible bone and soft tissue loss
  • Compound fracture
    Severe and tooth bearing area fractures
  • Pathological fracture
    (osteomyelities, neoplasm and generalized skeletal disease)

Sites of fractures

Mandible Fracture

  • Condyle fracture
  • Intracapsular fracture
  • Extracapsular fracture
  • High condyle neck fracture
  • Low condylar fracture
  • Angle/ ramus fracture (body fracture)
  • Canine region (parasymphesial fracture)
  • Midline fracture (symphesis fracture)
  • Coronoid fracture (rare)

Incidence of mandibular fractures

  • Body fractures 33.6%
  • Subcondylar fracture 33.4%
  • Fractures at the angle 17.4%
  • Alveolar fractures 6.7%
  • Ramus fractures 5.4%
  • Midline fractures 2.9%
  • Fracture of coronoid process 1.3%
  • Oikarinen & Malmstrom 1969

Favourable or unfavourable

  • They can be vertically or horizontally in direction
  • They are influenced by the medial pterygoid-masseter “sling”
  • If the vertical direction of the fracture favours the unopposed action of medial pterygoid muscle, the posterior fragment will be pulled lingually
  • If the horizontal direction of the fracture favours the unopposed action of messeter and pterygoid muscles in upward direction, the posterior fragment will be pulled lingually
  • Favourable fracture line makes the reduced fragment easier to stabilize

Effects of muscles on displacement

  • Transverse midline fracture (symphesial) stabilizes by the action of mylohyoid and geniohyoid
  • Oblique fracture (parasymphesial) tends to overlap under the influence of muscles action
  • Bilateral parasymphesial fracture results in backward displacement associated with loss of tongue control when the level of consciousness is depressed

Condylar fractures

  • The most common mandibular fracture:
  • Unilateral or bilateral
  • Intracapsular or extracapsular
  • Antero-medial displacement is common but it may remain angulated with the ramus
  • Dislocation of the glenoid fossa and fracture of petrous temporal bone which is very rare

Sign and symptoms

  • Swelling, pain, tenderness and restriction of movement
  • Deviation of mandible towards the side of fracture
  • Gagging of occlussion (premature contact on the posterior teeth) with bilateral condylar displaced or over-riding fractures
  • Displacement of mandible toward the affected side
  • Anterior open bite on opposite side of fracture
  • Laceration of EAM****
  • Retroauricular ecchymosis****
  • Cerebrospinal leak and otorrhea in association with skull base fracture

Sequlae of TMJ injury

  • Artheritic changes
  • Haemartherosis, fibrosis and aknylosis
  • Meniscal damage and detachment
  • TMD
  • Staph infection with condylar backward displacement and external auditory meatus injury
  • Meningitis with petrous temporal bone fracture and intracranial involvement

Coronoid process fracture:

  • Rare fracture caused by direct trauma to ramus and results from reflux contraction of temporalis
  • Can be seen following operation of large ramus cyst
  • Elicit tenderness over the anterior part of ramus
  • Development of tell-tale haematoma

Fracture of the ramus:

  • Type I Single fracture
  • Mimics low condylar fracture that runs below the sigmoid notch
  • Type II comminuted fracture
  • Common in missile injuries and appears to be with little displacement due to effects of messeter and medial pterygoid muscles

Fracture of the angle and body

  • Pain, tenderness and trismus
  • Extra-oral swelling at the angle with obvious deformity
  • Step deformity behind the molar teeth
  • Movement and crepitus at the fracture site
  • Derangement of occlussion
  • Intra-oral buccal and lingula heamatoma
  • Involvement of IDN
  • Gingival tear if fracture in dentated area
  • Tooth involvement and possible longitudinal split fracture

Midline fracture

  • The most common missed fracture (always fine crack)
  • Can be symphesial or parasymphesial fracture
  • Commonly associated with one or both condyles fracture
  • Unilateral fracture leads to over-riding of the fragments and bilateral  may contribute in loss of voluntery tongue control
  • Long canine tooth represent a weak area and contributes to parasymphesial fracture
  • Rarely runs across mental foramen

Signs and symptoms

  • Pain and tenderness
  • Swelling and odemea
  • Development of step deformity
  • Mental anesthesia
  • Heamatoma in the floor of mouth and buccal mucosa
  • Soft tissue injury of the chin and lower lip
  • If associated with condylar fractures
  • Absence of condyle movement on the contrlateral side
  • Deviation of mandible
  • Anterior open bite
  • Gagging of oclussion
  • Limitation of mouth opening

Clinical assessment and diagnosis

  • History of trauma (traumatized patients with possible head injury) and facial injuries
  • Clinical Examination
    •  Extroral
      • Inspection (assessment of asymmetery, swelling, ecchymosis, laceration and cut wounds)
      • Palpation for eliction of tenderness, pain, step deformity and malfunction
    •  Intra- and paraoral
      • Bleeding, heamatoma, gingival tear, gagging of occlussion and step deformity and sensory and motor deficiency
  • Radiographs

Radiographs

  • Plain radiograph
  • OPG
  • Lateral oblique
  • PA mandible
  • AP mandible (reverse Townes)
  • Lower occlusal
  • CT scan
  • 3-D CT imaging
  • MRI

Principles of treatment

  • Similar to elsewhere fractures in the body
  • Reduction of fragments in good position
  • Immobilization until bony union occurs
  • These are achieved by:
    • Close reduction and immobilization
    • Open reduction and rigid fixation
    • Other objective of mandible fracture treatment:
    • Control of bleeding
    • Control of infection

Definitive treatment

  • Soft tissue repair
  • Debridment
  • Irrigation with saline and antibiotics
  • Closure in layers
  • Dressing
  • Reduction and fixation of the jaw
    •  Close reduction and IMF (traditional method by means of manipulation)
    •  Open reduction and semi-rigid fixation (using inter-ossous wirings)
    •  Open reduction and rigid fixation (using bone palates osteosynthesis)
  • Objective:
    • Restoration of functional alignment of the bone fragments in anatomically precise position utilizing the present teeth for guidance
  • Close reduction

Mandible Fracture Mandible Fracture

  • Arch bars
  • Jelenko
  • Erich pattern
  • German silver notched
  • Cap splints
    •  IMF prior to rigid fixation
    •  For the purpose of close reduction

Close reduction

  • Bonded brackets
  • IMF screws
  • Dental wiring:
    • Direct wiring
    • Eyelet wiring
  • Local anesthesia or sedation
  • Minimal displacement
  • IMF for 6 weeks
  • Treatment can be performed under GA or LA and when surgery is contraindicated

Fracture mandible in children

  • Close reduction
  • Open reduction and fixation
  • Plating at the inferior border
  • Resorpable plates

Gunning’s splint

Mandible Fracture

  • Old modality
  • Edentulous patient
  • Rigid fixation is not possible
  • To establish the occlusion

Open reduction and fixation

  • Intraoral approach
  • Extraoral approach
    ▶ Submandibular approach

Rigid fixation

Mandible Fracture

  • Intraossous wiring
  • Plates and screws
  • Kirchener wire
  • Lag screws

Reconstruction palate

  • Severe trauma
  • Loss of part of the bone

Condylar fractures

  • Intraoral approach
  • Ramus  incision
  • Extraoral approach
  • Preauricular approach
  • Retromandibular approach

IMF

  • Transosseous wiring
  • Circumferential wiring
  • External pin fixation
  • Bone clamps
  • Trans-fixation with Kirschner wires

Osteosynthesis

  • Non-compression small plates
  • Compression plates
  • Miniplates
  • Lag screws
  • Resorbable plates and screws

Teeth in the fracture line

  • The fracture is compound into the mouth
  • The tooth may be damaged or lose its blood supply
  • The tooth may be affected by some preexisting pathology

Management of teeth retained in fracture line

  • Good quality intra-oral periapical radiograph
  • Insinuation of appropriate systemic antibiotic therapy
  • Splinting of tooth if mobile
  • Endodontic therapy if pulp is exposed
  • Immediate extraction if fracture becomes infected
  • Follow up for 1 year and endodontic therapy if there is a loss of vitality

Absolute indications

  • Longitudinal fracture
  • Dislocation or subluxation from socket
  • Presence of periapical infection
  • Infected fracture line
  • Acute pericoronitis

Relative indications

  • Functional tooth that would be removed
  • Advanced caries or periodontal diseases
  • Doubtful tooth which would be added to existing denture
  • Tooth in untreated fracture presenting more than 3 days after injury