Indian Dental Academy's Guide to Mandibular Fractures

INDIAN DENTAL ACADEMY
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www.indiandentalacademy.com


MAXILLOFACIAL TRAUMA

MANDIBULAR FRACTURES

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



Mandible fractures
sent


Index
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Introduction
Terminologies
Classification
Incidence & Pathogenesis
Clinical Examination
Radiographs
Treatment Options
Closed Reduction & Open Reduction
Fixation techniques
Surgical Approaches to open reduction
Complications

 It must be emphasized that any force great

enough to cause a fracture of a mandible is
capable of injuring any other organ system in
the body
 Patients rarely die of mandibular fractures ,

so the clinician has time to carefully and
thoroughly evaluate the nature and extent of
mandibular injuries.


Surgical anatomy
The positional suseptibility of individual teeth to injury
1)

The U/L ant teeth are most liable to injury, with the upper
C.I in the most vulnerable position .the increased over jet
associated with the anatomical variant known as angles
class 2 .

2)

Indirectly an upward blow on the mandible with the
musculature relaxed,or a fall on the point of the chin ,
causes the teeth to meet sharply and indirect tooth injury
may result.

3)

The teeth most susceptible are the upper premolars,
being predisposed by their shape and that of the opposing
teeth to antero-posterior splitting of the crowns .

 The mandible is basically a tubular long bone which is bent into

a blunt V- shape.

 The cortical bone is thicker anteriorly at the lower border while

posteriorly the lower border is relatively thin.

The mandible differs from all other long bones in two aspects
(a) Any movement inevitably causes both condyles to move with
respect to the skull base.

(b) Although anatomically the condyles are the articulating
surfaces of the mandible, functionally the occlusal surface of
the mand teeth subserves this role. In a functional sense , the
oral cavity is analogous to joint space.

The teeth
 The presence of the teeth is extremely helpful in the reduction

and fixation of mand #es.

 The teeth may be regarded as row of bone pins offering direct

control of attached fragments of bone with out any of the
problems associated with surgically introduced metal pins.

 Presence of teeth are the weakness of the mandible ,+nce of

teeth are the strength of maxilla .

 The alveolar process is invested over half of its depth by tightly

attached mucoperiosteum this soft tissue tears in all cases
directly over the # both bucally and lingually such #es are thus
(open) compound in to the oralcavity and exposed to possible
infection.

 The mucoperiosteumof the edentulous

mandible is , by contrast ,an intact sleeve and
is less frequently ruptured in association with
underlying #es.in consequence these remain
closed and the mucoperiosteum limits their
displacement.


Strength of the mandible
 Bones fractures at the sites of tensile strain ,

since their resistance to compressive forces is
greater.
Huelke(1961) and Hodgson(1967)

 The mandible is a strong bone, the energy required to #

in being of 44.6-74.4kg/m, which is about same as
zygoma and about half that of frontal bone .


Condylar region
 The zygomatic arch gives protection to the condyle from direct

trauma.

 The subcondylar fracture is invariably produced indirectly as a

result of violence to the mental prominence or contra lateral
body of the mandible.

 An anterior capsular tear associated with rupture of fibers of

the lateral pterygoid which is inserted into the disc, would
cause inability to close the jaw fully,due to disc being displaced
posteriorly.

 Posterior tear with out the rupture with the rupture of these

muscle fibers' could result in episodes of interference with
opening due to the anterior displacement of disc.

Ramus and coronoid process
 #es of ramus exhibit very little displacement

of the fragments due the splinting effect of
the masseter and medial pterygoid.
 Occasionally due to the power full
contraction of the temporalis muscle ,# of
the Coronoid process occurs.


# of ANGLE OF MANDIBLE :
It is the second common site of fracture after condyle.
It is imp. To distinguish ! ) clinical angle
!! ) surgical angle,
!!!) anatomical angle.
Clinical angle : It is the junction b/n alveolar bone & ramus at
the origin of the internal oblique line.


Surgical angle : Junction b/n body of mandible & ramus at the
origin of external oblique ridge.

 Anatomical or Gonion angle : where lower border meets the

posterior border of ramus.

In most cases the fracture line extends from
surgical angle downwards and backwards ,
terminating at the lower border anterior to
the masseter muscle.
when a 3rd molar tooth is present the#
commonly extends through its crypt or
socket.

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


Types of #
1).Simple :Fracture line does not communicate with the exterior
 Greenstick fracture (rare, exclusively in children)
 Fracture with no displacement (Linear)
 Fracture with minimal displacement

 2).Compound:Fracture line communicates with interior
(oral cavity) or exterior (skin)
3).Comminuted: Multiple fragments at any one fracture site.
(Extensive breakage with possible bone and soft tissue loss)
4).Complicated: Along with injury to bone, direct or indirect
injury to adjacent nerves,blood vessels or joints
5).Impacted: Some linear fractures inter digitate to such an
extent that there is no appreciable clinical
movement. (Seen more commonly in maxilla)

6.

Greenstick: In children due to elasticity of bone, the bone
bends producing distortion without break in continuity
(discontinuity in cortex on one side & continuity on other)

7.

Pathological : Due to underlying pathology the bone is weak
enough to be fractured by minimal trauma or muscle
contraction.
(osteomyelities, neoplasm and generalized skeletal disease)

8. Direct: Fracture adjacent to the point of contact of trauma
9. Indirect: Fracture arises at a point distant from the site of
contact of trauma.

Classification
DINGMAN & NATVIG
1964


Based on anatomic location
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Symphysis ( Midline )
Parasymphysis
Body
Angle
Ramus
Coronoid process
Condylar process
Alveolar Process.


KAZANIAN & CONVERSE
1974


Based on presence or absence
of teeth in relation to the
line of fracture.
Class I Teeth are present on both sides of fracture
line
Class II Teeth only one side of fracture line
Class III Patient edentulous


Based on level of
fracture(ROWE & KILLEY

1968)

1. Those not involving basal bone
( Alveolar fractures)
2. Those involving basal bone


Based on relation to the
overlying tissues(KRUGER
1974)
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

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Simple
Compound
Comminuted


KRUGER & SCHILLI
1982
1.

Relation to External environment
i.
Simple / Closed
ii. Compound / Open

2.

Types of fractures
i.
Incomplete
ii. Green Stick
iii. Complete
iv. Comminuted

3. Dentition of the jaw with reference to the

use of splints
i.

Sufficiently edentulous jaw

ii.

Primary & mixed dentition


4. Localization

i. Fractures of the Symphysis region (b/w the canines)
ii. Fractures of the Parasymphysis

(canine region)

iii.Fractures of the Body
(b/w the canine & the angle)
iv.Fractures of the Angle
v. Fractures of the Ramus
(b/w the angle & the sigmoid notch)
vi. Fractures of the Coronoid process

vii.Fractures of the Condylar process

Based on muscle pull and direction
 Horizontally favorable
 Horizontally unfavorable

 Vertically favorable
 Vertically unfavorable


Horizontally Favorable

Vertically Favorable

Horizontally Unfavorable

Vertically Unfavorable


Spiessel’s

classification

Based on
1) No of # fragments
2) Location of fracture
3) Status of occlusion
4) Soft tissue involvements
5) Associated fracture


 Classification of # by no of fragments and

1)
2)
3)

4)
5)

presence of bone defect(F1 to F4)
F0 : incomplete #
F1 : single #
F2 : multiple #
F3 : comminuted #
F4 : # with bone a defect( # with bone loss)



1)
2)
3)
4)
5)
6)
7)
8)

Classification of #es by site(l1 to l8)
l1 : precanine
L2 : canine
L3 : postcanine
L4 : angle
L5 : supra- angular
L6 : condylar process
L7 : coronoid process
L8 : alveolar process

 Classification of #es based on occlusion changes(0o

to 02)
1) O0 : no malocclusion
2) 01 : malocclusion
3) O2 : non-existent occlusion( edentulous mandible)
Classification of #es by soft tissue involvement
1) s0: closed
2) S1 : open intraorally
3) S3 : open extraorally
4) S3 : open intra- and extraorally
5) S4 : soft tissue defect

 Associated #es(A0 TO A6)
1) A0 : none

2) A1 : fractures(or) loss of tooth
3) A2 : nasal bone
4) A3 : zygoma

5) A4 : lefort -1
6) A5 : lefort -2
7) A6 : lefort- 3

Point of Impact
Chin
 To fracture single subcondyle : 425 Lb
 To fracture both subcondyle : 550 Lb
 To fracture symphysis
: 550 – 900 Lb
Lateral aspect of Md.
 To fracture Md

: 300 – 700 Lb


Epidemiology
 Sites of weakness
 Third molar (esp. impacted)

 Socket of canine tooth
 Condylar neck


Pathogenesis of Fracture
 When an impact force is delivered on Md : The

bone bends inwards producing compressive
forces in the impacted (lateral ) surface and
tensile forces on the lingual (medial) surface.


Fracture results when the tensile strain
overcomes the resistance of the bone, beginning
on the medial side of Md and progressing
THROUGH the bone towards the impact point.


B

L
L

B

B

-

+

-

+
+
B

+

L
B

-

+

-

L


L

Mandibular Forces


ETIOLOGY
 A # may be from 1) direct violence 2) indirect
violence 3) excessive muscle contraction.
Factors influencing the displacement of #
1) The degree of force
2) The resistance to the force offered by facial
bones.
3) The direction of force
4) The point of application of force
5) The cross sectional area of the agent or object
struck
6) The attached muscles

 The effect of force applied from an
 antero-posterior direction

 superior direction
 inferior direction
 Lateral direction


Clinical Examination


1) General physical examination
2) Local examination of mand #

a) extra-oral examination
b) intra oral examination


Local examination
 The first step would be to consider the patients chief complaint :

Patients often complain of the following:
1)Pain or tenderness is often present at the site of impact with the possibility
of a direct fracture, or at a distant site in the case of an indirect fracture.

2) Difficulty chewing. Pain could be limiting mandibular function or there
may be a malocclusion or mobility at the fracture site.
3) Malocclusion. The patient may be able to tell the clinician of an alteration
in the bite from the normal.
4) Numbness in the distribution of the inferior alveolar nerve. This usually
indicates a displaced fracture in the region of the body or angle of the
mandible on the affected site.

Signs and symptoms


Soft tissue
injuries
 Inspection may reveal a full thickness wound of the lower

lip or a ragged laceration on its inner aspect caused by
impaction against the lower anterior teeth.

 Lacerations of the gingiva and deformity of the alveolus

occurs.

 In the anterior region of the mandible a degloving injury

may occur as a result of impaction at the point of chin on
some resilient surface such as soft earth.the jaw does not #
but the soft tissue is rotated violently over the point of the
chin and horizontal tear occurs in the buccal sulcus at the
junction of attached and free gingiva.


Damage to the teeth
1) fracture of the crown of the individual teeth.
2) Any missing fragments of crown or missing fillings should be noted as
these may be
embedded with in the soft tissues or more rarely swallowed or inhaled.
3) Exposure or near exposure of the pulp chamber.
4) Fractures of the roots of teeth.
5) Subluxation of teeth causes derangement of occlusion.
6) Vertical split or a horizontal # just below the gingival margin results from
indirect trauma against opposite dentition.

Fractures of the parasymphysis
and symphysis
1)

Sub lingual ecchymoses- Coleman's sign

2)

Crepitation on palpation

3)

Restricted mouth opening.

4)

Inability to close the jaw causing premature dental contact.

5)

A retruded chin can be caused by bilateral parasymphyseal
fracture.

6)

paraesthesia


# of the body
 Swelling and tenderness similar to that as seen in # of the angle

of the mandible.

 #es between the adjacent teeth tend to cause gingival tears.
 When there is a gross displacement, inf dental artery may be

torn, and this can give rise to severe intraoral haemorrhage.

 Ecchymosis in the floor of the mouth.
 Flattened appearance on the lateral aspect of the face.

 Crepitation on palpation.


# of the angle
 Anterior open bite is seen in bilateral angle fracture.
 Ipsilateral open bite is seen in unilateral angle fracture
 A deficient mand angle can occur with the unfavorable

angle #es in which proximal fragments rotates superiorly.

 Appearance of an elongated face may be a result of

bilateral angle #es allowing anterior mand to be displaced
downward.

 Inability to close the jaw causing premature dental contact.

 Swelling at the angle externally
 Step deformity behind last molar tooth.
 Restricted mouth opening

 Small haemotoma intraorally adjacent to angle
on either lingual or buccalside.
 Paraesthesia.

# of ramus
 Swelling and ecchymosis is usually noted

both extra and intra orally.
 Tenderness
 Restricted mouth opening
 Flattened appearance on the lateralaspect of
face.


Classification of edentulous
atrophic mandible (luhr etal)
1) Class 1: moderate atrophy (16-20mm)

2) Class ll: significant atrophy(11-15mm)
3) Class lll: extreme atrophy (10mm or less)


Radiographs
Panoramic radiograph
 Single most information radiograph for diagnosing
Md fractures (shows entire mandible, including
condyles)
 Advantages

Simplicity of technique
Ability to visualize entire mandible in one radiograph
Generally good detail

Disadvantages:
 Requires patient to be upright
(impractical in severely traumatized patient)
 Difficult to appreciate buccal – lingual bone
displacement or
 Medial condylar displacement
 Lacking fine detail in -TMJ area
- Symphysis region
- Dental & Alv. Process region
 Equipment not present in all hospital radiology
facilities


Lateral Oblique
Ramus
Angle
Post Body
 Disadvantages

Condyle region, Bicuspid & Symphysis region unclear


PA View ( Caldwell)
 Medial or lateral displacement of fractures of

the ramus, angle, body and Symphysis.
 Disadvantages:
 Condylar region is not well demonstrated

(but midline or Symphyseal fractures are)


Mandibular Occlusal view
Demonstrates discrepancies in the medial and
lateral position of the body fractures and also
shows anteroposterior displacement in the
symphysis region.


Reverse Towne’s
 Ideal for showing medial displacement of
condyle and condylar neck fractures.
 Transcranial lateral views of TMJ


 TREATMENT:

Reduction
Fixation

Immobilization


Goals Of Management of
fracture
1. Restore function

(by bony union & reestablishing Pre # strength)
2. Restore contour defect
3. To prevent infection at fracture site

Restore function means: Mastication, Speech,Mouth
opening restoring these parameters to normally.

Closed Reduction

 Is a ‘blind’ reduction relying on the fragments

‘locking’ together. In closed reduction, occlusion,
palpation or post op X-rays are used as a guide to
the accuracy of the reduction. This is more likely
done in the cases where the periosteum is intact.


Closed reduction Indications
 Nondisplaced favorable fractures
 Grossly Comminuted fractures
 Fractures exposed by significant loss of overlying soft tissuse.
 Edentulous Mandibular fractures.
 Mandibular fractures in children with developing dentition.
 Coronoid process fracture.

 Condylar fractures.


Open Reduction.
Involves exposure of the fracture either through the
skin or the mucosa.
Reduction of fracture segments can be done by
Manual manipulation
Traction


Open reduction Indications
 Displaced Unfavorable fractures of Angle,body
or parasymphysis
 Multiple fractures of the facial bones
 Midface fractures and displaced bilateral
condylar fractures
 Fractures of Edentulous mandible with severe
displacement of fragments
 Edentulous maxilla opposing mandibular
fracture
 Delay of treatment and interposition of soft
tissue

Fixation
 To prevent mobility of fracture segments to aid in healing. Can

be Direct fixation
Indirect fixation

 Direct fixation:

Fracture site is opened, visualized and
reduced stabilized across the fracture site.
eg.Non rigid : Transosseous wiring
Semi rigid: Mini bone plate
Rigid
:
Compression bone plate.

 Indirect fixation: Stabilization of the proximal and distal

fragments of the bone at a site distant from the fracture line

Eg. For Md fracture, IMF
External pin fixation.

Methods available for Fixation


Fixation
Indirect skeletal
(Fixation applied to)
TEETH

Direct Skeletal
(Direct fixation of
BONE)


Indirect skeletal
(Fixation applied to the TEETH)
1. Dental wiring
Direct interdental wiring.
Indirect interdental wiring (Eyelet or Ivy)
Continuous or multiple loop wiring

2. Arch Bars
3. Cap Splints
4. ‘Gunning type ‘ splints

Indirect skeletal
1. Dental wiring
a. Direct interdental wiring


Indirect skeletal
1.Dental wiring
b. Indirect interdental wiring
(Eyelet or Ivy loop)
(Button wiring Leonards)


Indirect skeletal
1. Dental wiring
c. Continuous or multiple loop wiring
( Stouts method)
( Obwegeser method)


Indirect skeletal
2. Arch Bars
Custom made
Commercially available
(Baker precast bar)
(Jelenko)
(Erich)
(Directly bonded)
(Krupps)
(Risdon)


Indirect skeletal

3. Cap Splints
( Cast silver cap splints)
( Acrylic cap splints )


Indirect skeletal
4. Gunning type splints
( Prefabricated Gunning type splint)
( Old Dentures)
( Disposable trays)


SURGICAL APPROCHES
 The surgeon may elect to extend the

laceration to provide adequate access to the
fractured area, following the relaxed skin
tension lines (RSTL).


 Vestibular incisions

The intraoral approach is the usual access for simple
fractures of the body, symphysis, and angular regions.
The approach can be extended posteriorly (dashed line)
for better access to the body, angle and ramus regions.


 When the incision is extended posterior to the canine

teeth, the mental nerve can be damaged. Keep the
incision superior to the mental nerve in the body region.
Particularly in the extended intraoral approach, care
must be taken to protect the mental nerve in the anterior
body region.


Vestibular approach


POSTERIOR VESTIBULAR INCISION
 The sensory buccal nerve crosses the upper anterior rim

of the mandibular ascending ramus in the region of the
coronoid notch. It is usually below the mucosa running
above the temporalis muscle fibers. When the posterior
vestibular incision is carried sharply along the bony rim,
the buccal nerve is at risk of transsection, followed by
numbness in the buccal mucosal region. Therefore, to
protect the nerve, the posterior dissection is to be
extended bluntly as soon as the lower coronoid notch is
reached.


 The transbuccal trocar may also assist the

surgeon in positioning posterior and inferior
screws, sometimes avoiding the need for an
extraoral approach.


SUB MENTAL INCISION


EXTENDED SUB-MENTAL
 This may be necessary in complex fractures

such as comminuted, atrophic, and severe
bilateral fractures.


 Variations

The incision can either be parallel to the
inferior border of the mandible or be placed
in an existing skin crease for maximum
cosmetic benefit.


 In order to protect the marginal mandibular

branch of the nerve, the platysma is
undermined bluntly with scissors prior to
dividing it with a scalpel.
 The platysma muscle is divided sharply,
preferably 2-3 cm below the mandibular
border, not necessarily at the same level of
the skin incision.


RETRO MANDIBULAR APPROCHES
 Transparotid approach: skin incision A

vertical incision through skin and
subcutaneous tissue is made, extending from
just below the ear lobe towards the
mandibular angle. It should be parallel to the
posterior border of the mandible.


Retro parotid incision
 A frequently used alternative to the

retromandibular transparotid approach
described above is one in which the parotid
gland is lifted rather than dissected through.
 This requires the incision to be placed more
posteriorly which means that exposure of the
mandible is more limited. Rather than
approaching the mandible from directly over
the ramus, it is approached more posteriorly

Rhytidectomy approach


Methods available
for Direct Skeletal
fixation


Direct Skeletal
(Direct fixation of BONE)
1. Trans osseous wiring
a. Upper border
b. Lower Borders
2. Circumferential straps
3. Bone plating
4. Intramedullary pinning
5. Titanium mesh
6. Ext. Pin Fixation
7. Bone clamps
8. Bone staples
9. Bone Screws

Direct Skeletal
a. Upper border
Oblique
Horizontal mattress
Single loop


Direct Skeletal

b. Lower Borders
Hayton Williams
4 hole technique


Direct Skeletal

2. Circumferential straps


Direct Skeletal
3. Bone plating
Miniplates
Compression plates
Lag screws


Locking versus nonlocking plates
There are several advantages to a locking plate/screw system:

Conventional plate/screw systems require precise adaptation of the plate to the
underlying bone.
Without this intimate contact, tightening of the screws will draw the bone
segments toward the plate, resulting in alterations in the position of the osseous
segments and the occlusal relationship.
Locking plate/screw systems offer certain advantages over other plates in this
regard; the most significant being that it becomes unnecessary for the plate to
intimately contact the underlying bone in all areas.

As the screws are tightened, they "lock" to the plate, thus stabilizing the segments
without the need to compress the bone to the plate. This makes it impossible for
the screw insertion to alter the reduction.


Another potential advantage in locking plate/screw systems is that they do not
disrupt the underlying cortical bone perfusion as much as conventional plates,
which compress the undersurface of the plate to the cortical bone.
A third advantage to the use of locking plate/screw systems is that the screws are
unlikely to loosen from the plate. This means that even if a screw is inserted into a
fracture gap, loosening of the screw will not occur. Similarly, if a bone graft is
screwed to the plate, a locking head screw will not loosen during the phase of graft
incorporation and healing.
The possible advantage to this property of a locking plate/screw system is a
decreased incidence of inflammatory complications due to loosening of the
hardware.
Locking plate/screw systems have been shown to provide more stable fixation
than conventional nonlocking plate/screw systems

Direct Skeletal

4. Intramedullary pinning (major,1938)
Employed by mcdowell,Barrett, and Fryer (1954).


Direct Skeletal
5. Titanium mesh


Direct Skeletal
6. External Pin Fixation


Direct Skeletal

7. Bone clamps (penn&brown,1944
8. Bone staples (laws,1977)
9. Bone Screws


Immobilization
 After the fragments are aligned in proper

symmetry they are fixed and immobilized in this
position until bony union occurs.
 To resist displacing forces acting on fracture site
to allow a clinical fracture union
 Indicated in cases where Nonrigid Fixation
methods are used and the site in question will be
subjected to force.


COMPLICATIONS
 Intra-op
 Immediate post-op

 Post-op


Intra –op complication
 Surgical approches Encountering vital structures like-mental

nerve, marginal mandibular nerve, facial
nerve, facial artery.
 Infections
 Hemmorage


Immediate

post-op

 Infection
 Hemmorage

 G.A. related


Post-op
 Mal occlusion
 Mal-union

 Non-union
 Infections




Thank you


Indian Dental Academy's Guide to Mandibular Fractures

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Indian Dental Academy's Guide to Mandibular Fractures