MANDIBULAR FRACTURESSOYEBO O.A

OUTLINE• INTRODUCTION• CLASSIFICATION• AETIOLOGY• EPIDEMIOLOGY• SIGNS & SYMPTOMS• INVESTIGATION• MANAGEMENT

INTRODUCTION• Fracture of the mandible occurs more frequently than that of any other facial

skeleton.• It is the one serious facial bone injury that the average practicing dental surgeon

may expect to encounter, albeit on rare occasions, at his surgery.• It is also a facial fracture which he may have the misfortune to cause as a

complication of tooth extraction.• Broadly divided into:1. Fractures with no gross communition of the bone and without significant loss

of hard and soft tissues2. Fractures with gross communition of the bone and with extensive loss of both

hard and soft tissues.

ANATOMY• Lower jaw bone• U shaped body• 2 vertically directed rami• Condylar process• Coronoid process

• Oblique line• Mental foramen

INTERNAL ANATOMY• Mandibular foramen• Lingula• Pterygoid fovea• Mylohyoid line• Fossae• Submandibular• Sublingual• Digastric

• Mental spines• Genioglossus• Geniohyoid

MUSCULATURE: jaw elevators• Masseter muscle: from

zygoma to angle and ramus• Temporalis muscle: from

infratemporal fossa to coronoid and ramus.• Medial pterygoid muscle:

medial pterygoid plate and pyramidal process into the lower mandible.

MUSCULATURE: jaw depressors• Lateral pterygoid muscle:

lateral pterygoid plate to condylar neck and TMJ capsule

• Mylohyoid muscle: Mylohyoid line to body of hyoid

• Digastric muscle: mastoid notch to digastric fossa

• Geniohyoid muscle: inferior genial tubercle to anterior hyoid bone

INNERVATION• CN3; mandibular nerve

through the foramen ovale• Inferior alveolar nerve

through the mandibular foramen• Inferior dental plexus• Mental nerve through the

mental foramen.

BLOOD SUPPLY• Internal maxillary artery• Inferior alveolar artery• Mental artery

CLASSIFICATION OF FRACTURES• Type of fracture• Site of fracture• Cause of fracture

TYPE OF FRACTURE• Simple• Includes a closed linear fractures of the condyle, coronoid, ramus and

edentulous body of the mandible.

• Compound• Fractures of tooth bearing portions of the mandible, into d mouth via the

periodontal membrane and at times through the overlying skin.

• Communited• Usually compound fractures characterized by fragmentation of bone

• Pathological• Results from an already weakened mandible by pathological conditions.

SIMPLE

COMPOUND

COMMUNITED

SITE OF FRACTURE• Dentoalveolar• Condyle• Coronoid• Ramus• Angle• Body (molar and

premolar areas)• Parasymphysis• Symphysis

SITE OF FRACTURE

A- CONDYLARB- CORONOIDC-RAMUSD- ANGLEE- BODY(MOLAR PREMOLAR AREASF- PARASYMPHYSISG- SYMPHYSISH-DENTO-ALVEOLAR

CAUSE OF FRACTURE• Direct violence• Indirect violence• Excessive muscular contraction• Fracture of the coronoid process because of sudden reflex contracture of the

temporalis muscle.

PATTERN OF FRACTURE• Unilateral fracture• Bilateral fracture• Multiple fracture• Communited fracture

AETIOLOGY• Road traffic accidents• Interpersonal violence• Contact sports• Industrial trauma• Falls

EPIDEMIOLOGY• The mandible is one of the most commonly fractured bones of the

face and this is directly related to its prominent and exposed position.• Oikarinen and Lindqvist (1975) studied 729 patients with multiple

injuries sustained in RTA. The most common facial fractures were in the mandible.• Mandible (61%)• Maxilla (46%)• Zygoma(27%)• Nasal Bone (19%)

• Studies have shown that the incidence of mandible fractures are influenced by various etiological factors e.g.• Geography• Social trends• Road traffic legislations• Seasons

• Site of Fracture: Oikarinen and Malmstrom (1969) analyzed 600 mandible fractures. On analysis the following results were obtained:• Body of mandible (33.6%)• Sub- condylar area(33.4%)• Angle (17.4%)• Dentoalveolar (6.7%)• Ramus (5.4%)• Symphyseal 2.9%• Coronoid 1.3%

• Even though the body of the mandible has the highest incidence when it comes to mandibular fracture, the condyle remains the commonest site for mandibular fracture

SIGNS AND SYMPTOMS• GENERAL• SPECIFIC

GENERAL SIGNS AND SYMPTOMS• Swelling• Pain• Drooling• Tenderness • Bony discontinuity• Lacerations

• Limitation in mouth opening• Ecchymosis• Fractured, subluxed, luxated

teeth.• Bleeding from the mouth.

SPECIFIC SIGNS AND SYMPTOMS• DENTOALVEOLAR FRACTURES

• Lip bruises and laceration• Step deformity• Bony discontinuity• Fracture, luxation or subluxation of teeth• Laceration of the gingivae

• FRACTURE OF THE BODY• Swelling• pain • Tenderness• Step deformity• Anaesthesia or paraesthesia of the lip• Intra oral hemorrhage

• SYMPHYSEAL/PARASYMPHYSEAL FRACTURES• Tenderness• Sublingual haematoma• Loss of tongue control• soft tissue injury to the chin and lower lip

• FRACTURE OF THE RAMUS • Swelling• Ecchymosis• Pain• Trismus

• FRACTURE OF THE ANGLE • Swelling• Posterior gag• Deranged occlusion• Anaesthesia or paraesthesia of lower lip• Haematoma• Step deformity behind the last molar tooth• Tenderness

• CORONOID FRACTURE• Tenderness over the anterior part of the tragus• Haematoma• Painful limitation of movement• Protrusion of mandible may be present.

• SYMPHYSEAL/PARASYMPHESEAL FRACTURES• Tenderness• pain• Step deformity• Sublingual haematoma• Loss of tongue control• May have soft tissue injury to the chin and lower lip

• CONDYLAR FRACTURE (unilateral/bilateral and Intracapsular/extracapsular)

• Unilateral condylar fractures• Swelling over the TMJ• Hemorrhage from ear on the affected side• Battle’s sign• Locked mandible• Hollow over the condylar region after edema has subsided• rarely, Paraesthesia of lower lip• Deviation to the affected side upon opening• Painful limitation of movement

• Bilateral condylar fractures• Same as above• Limitation in mouth opening• Restricted mandibular movement• Anterior open bite

INVESTIGATION• Treatment plan for mandibular fractures is very dependent on precise

radiological diagnosis• RADIOGRAPHS• Essential radiographs

• Extra-oral radiographs• Intra-oral radiographs

• Desirable radiographs

• Oblique lateral radiographs (left and right)• Fracture of body proximal to

canine region• Fractures of angle, ramus and

condylar region

Essential Extra-oral Radiographs

• Posterior-anterior view• Shows displacement of

fractures in the ramus, angle, body

• Rotated posterior-anterior view• Fractures between Symphysis

and canine region

• Reverse Towne’s view• Ideal for showing

lateral or medial condylar displacement

Essential Intra-oral Radiographs• Periapical radiographs:• Association of tooth to line of fracture• Existing pathology related to tooth in line of fracture• Fracture of tooth in line of mandibular fracture

• Occlusal radiographs:• Association of root of tooth to line of fracture

Desirable Radiographs• Panoramic tomography• represents the best single

overall view of the mandible especially the condyles

• Standard linear tomography• Computed tomography (CT)

MANAGEMENT• Airway

• Tongue falling back• Blood clots• Fractured teeth segments• Broken fillings• Dentures

• Hemorrhage• Soft tissue lacerations• Support of bone fragments• Pain control• Infection control e.g. compound fractures• Food and Fluid

DEFINITIVE TREATMENT• Reduction• Restoration of a functional alignment of the bone fragments• Use of occlusion1. Open reduction2. Closed reduction

• Immobilization• To allow bone healing• Through fixation of fracture line1. Rigid2. Non-rigid

BONE HEALING• Bone healing is altered by types of fixation and mobility of the

fracture site in relation to function• Primary bone healing• Secondary bone healing

Bone Healing• Primary bone healing:• No fracture callus forms• Heals by a process of

1. Haversian remodeling directly across the fracture site if no gap exists (Contact healing), or

2. Deposition of lamellar bone if small gaps exist (Gap healing)

• Requires absolute rigid fixation with minimal gaps

Bone Healing

Contact Healing Gap Healing

Bone Healing• Secondary bone healing:• Bony callus forms across fracture site to aid in stability and immobilization• Occurs when there is mobility around the fracture site

Bone Healing• Secondary bone healing involves the formation of a sub

periosteal hematoma, granulation tissue, then a thin layer of bone forms by membranous ossification. Hyaline cartilage is deposited, replaced by woven bone and remodels into mature lamellar bone

Bone Healing

TEETH IN LINE OF FRACTURE• Teeth in line of fracture are a potential impediment to healing for the following

reasons

1. The fracture is compound into the mouth via the opened periodontal membrane2. The tooth may be damaged structurally or loose its blood supply as a result of

the trauma so that the pulp subsequently becomes necrotic3. The tooth may be affected by some pre-existing pathological process

• Indications for removal• Absolute• Relative

Absolute indications• Longitudinal fracture involving the root• Dislocation or subluxation of tooth from socket• Presence of periapical infection• Infected fracture line• Acute pericoronitis

Relative indications• Functionless tooth which would eventually be removed electively• Advanced caries• Advanced periodontal disease• Teeth involved in untreated fractures presenting more than 3days

after injury

Management of teeth retained in fracture line• Good quality intra-oral periapical radiograph• Appropriate antibiotic therapy• Splinting of tooth if mobile• Endodontic therapy if pulp is exposed• Immediate extraction if fracture becomes infected

IMMOBILIZATION• The period of stable fixation required to ensure full restoration of

function varies according to:1. Site of fracture2. Presence of retained teeth in the line of fracture3. Age of the patient4. Presence or absence of infection

• A simple guide to time of immobilization for fractures of the tooth bearing area of the mandible is as follows:

Young adultwith

Fracture of angleReceiving

Early treatmentIn which

Tooth removed from fracture line

3 weeks

• If:a) Tooth retained in fracture line: add 1 weekb) Fracture at Symphysis: add 1 weekc) Age 40yrs and above: add 1 or 2 weeksd) Children and adolescent: subtract 1 week

METHODS OF IMMOBILIZATION• Osteosynthesis without intermaxillary fixation

1. Non-compression small plates2. Compression plates3. Mini plates4. Lag screws

• Intermaxillary fixation

1. Bonded brackets2. Dental wiring

1. Direct2. Eyelet

3. Arch bars4. Cap splints

• Intermaxillary fixation with Osteosynthesis

1. Trans osseous wiring2. Circumferential wiring3. External pin fixation4. Bone clamps5. Transfixation with kirschner wires

CLOSED REDUCTION• Fracture reduction that involves techniques of not opening the skin or

mucosa covering the fracture site• Fracture site heals by secondary bone healing• This is also a form of non-rigid fixation

• “If the principle of using the simplest method to achieve optimal results is to be followed, the use of closed reduction for mandibular fractures should be widely used” Peterson’s Principle of Oral and Maxillofacial Surgery 2nd edition

• INDICATIONS1. Nondisplaced favorable fractures2. Mandibular fractures in children with developing dentition3. Condylar fractures

• CONTRAINDICATIONS:1. Alcoholics2. Seizure disorder3. Mental retardation4. Nutritional concerns5. Respiratory diseases (COPD)• Unfavorable fractures

• ADVANTAGES1. Low cost2. Short procedure time3. Can be done in clinical setting with local anesthesia or sedation4. Easy procedure

• DISADVANTAGES1. Not absolute stability (secondary bone healing)2. Oral hygiene difficult3. Possible TMJ sequelae

a) Muscular atrophy/stiffnessb) Decrease range of motion

• TECHNIQUES:1. Arch bars – Erich arch bars2. Ivy loops3. Essig Wire4. Intermaxillary fixation screws5. Splints6. Bridal wires

OPEN REDUCTION• Implies the opening of skin or mucosa to visualize the fracture and

reduction of the fractureCan be used for manipulation of fracture onlyCan be used for the non-rigid and rigid fixation of the fracture• INDICATIONSUnfavorable/unstable mandibular fractures Fractures of an edentulous mandible fracture with severe displacementDelayed treatment with interposition of soft tissue that prevents closed

reduction techniques to re-approximate the fragments

Open reduction/rigid fixation

Open reduction/ non rigid

SPECIAL CONSIDERATIONS• Edentulous mandible• Mandible in children

Mandibular Fractures in children• Mandible is resilient at this period• Line between cortex and medulla is less well defined• High ratio of bone to teeth substance

• Factors to consider in treating fractures in children• Interference with growth potential• Fixation in deciduous/mixed dentition• Unerupted teeth

Fracture of Edentulous mandible• Influencing factors:1. Decreased inferior alveolar artery (centrifugal) blood flow2. Dependent on periosteal (centripetal) blood flow3. Medical conditions that delay healing4. Decreased ability to heal with age5. Altered physical characteristics following tooth loss

• Methods of immobilization:• Direct Osteosynthesis1. Bone plates2. Transosseous wiring3. Circumferential wiring• Indirect skeletal fixation1. Pin fixation2. Bone clamps• Intermaxillary fixation using gunning type splints1. Used alone2. Combined with other techniques

COMPLICATIONS• Misapplied fixation• Infection• TMJ ankylosis• Nerve damage• Displaced teeth• Gingival and periodontal complications

• Malunion• Delayed union/Non union• Inadequate immobilization, fracture alignment• Interposition of soft tissue or foreign body• Incorrect technique

• Limitation in mouth opening• Scar formation

CONCLUSION• An adequate knowledge of the diagnosis and management of various

types of mandibular fracture is needed so as to provide the desired treatment in order to prevent unfavorable and adverse complications.