Fractures of the Mandible are the most common Fractures of the Facial region. Mandibular Fractures were first described in 1650 BC by Edwin Smith Papyrus. Mandible is the only moving bone in the Skull, it is also the strongest bone of the skull as it is made up of Cortical bone which is thicker in the posterior region and thinner in the anterior region. Alveolar process has a compact bone in buccal and lingual plates. Mandible is a V-shape long tubular bone which is strongest anteriorly in the mid line and the lest strongest at the condyles. This is the reason it is most prone to fractures in the Condyle region.
There are various muscles attached to the Mandible which are useful in its movement, depending on the position of the muscle to the fracture line it is termed as Favorable or Unfavorable Fracture. Fractures are classified into types based on not just the bone but also on the amount of damage to the soft tissue. The muscles attached to the Mandible are Masseter, Temporalis muscle, Medial pterygoid muscle, lateral pterygoid, mylohyoid and Geniohyoid. The Nerves Of Mandible – Cranial Nerve 3 (Occulomotor), Mandibular nerve, Inferior Alveolar nerve, Inferior dental plexus and Mental Nerve. Blood Supply to Mandible – Internal Maxillary artery, Inferior alveolar artery and Mental Artery.
Classification of Mandibular Fractures:
The fractures of Mandible are divided into types based on three major factors:
- Type of Fracture
- Site of Fracture
- Cause of Fracture
Along with the above mentioned classifications, there are other classifications given such as
- Based on presence of Serviceable Teeth at Fracture line
- Based on Involvement of Basal Bone
- Based on Line and Area of Fracture with muscle action
- Kruger and Schilli Classification
- Spiessel Classified Mandibular Fracture
Types of Mandibular Fractures:
- Simple Fracture: The fracture line is closed and linear on the condyle, ramus, coronoid process and edentulous body of the mandible.
- Compound Fracture: The fracture line is in the tooth bearing portions of the mandible. The fracture involves the overlying soft tissue, periodontal ligament and skin in some cases.
- Comminuted Fracture: The Fracture is a Compound type with fragmentation of bone, here the bone is either crushed or splinted.
- Complicated or Complex Fracture: The fracture involving injury to the adjacent soft tissue or surrounding organs. The Fracture type may be simple or Compound type.
- Greenstick Fracture: There is fracture of one Cortex (Buccal or Lingual) while the other cortex is bent.
- Pathological Fracture: The fracture involves a pre-existing bone disease and the cause can be a mild injury.
- Multiple Fractures: The fracture involves two separate fracture line without communicating with each other.
- Impacted: One Fractures segment is impacted into the other fragment completely.
- Indirect: The fracture line is located away from the site of trauma or injury.
- Atrophic: It is seen mostly in Edentulous jaws where the bone is atrophied and the fracture is spontaneous.
Most common Sites of Mandibular Fractures:
Let us look at the most common sites of fractures of Mandible which are given as
- Condyle: 29%
- Angle: 26%
- Body: 25%
- Symphysis: 15%
- Ramus: 4%
- Coronoid process: 1%
Mandibular Fracture based on Anatomic Location:
- Midline: Fracture line is located between the central incisors
- Body: Fracture line is located anywhere between the distal symphysis to a line coinciding with the alveolar border of the masseter muscle.
- Symphysis: It is located between the symphysis region
- Angle: It is positioned between the anterior border of the masseter muscle to the posterio superior attachment of the masseter muscle which is distal to the third molar.
- Canine region:
- Ramus: Fracture is positioned between the superior aspect of the angle and apex of the sigmoid notch.
- Condylar Process: Area of the condylar process superior to the ramus region
- Coronoid Process: Area of the coronoid process superior to the ramus region
- Dentoalveolar process: Fracture line in the alveolar process which contain Teeth
Based on Presence of Teeth in relation to the Fracture Line:
This classification was given by Kazanjian and Converse by considering the presence of Teeth in relation to the fracture line.
Class 1: Teeth are present on both sides of the fracture line
Class 2: Teeth are present only on one side of the fracture line
Class 3: Patient is Edentulous
Kruger and Schilli Classification of Mandibular Fractures:
This classification includes various factors
Relationship of Fracture to External environment:
- Simple or Compound
- Compound or Open
Types of Fracture:
Dentition of Jaw with reference to use of splints:
- Sufficiently dentulous jaw
- Edentulous or insufficiently dentulous jaw
- Primary and mixed dentition
Localization or Location of Fracture:
- Fractures of Symphysis between canines
- Fractures of canine region
- Fractures of body of mandible between canine and angle of mandible
- Fracture of angle of mandible in third molar region
- Fractures of mandibular ramus between angle of mandible and sigmoid notch
- Fractures of coronoid process
- Fractures of condylar process
Based on Involvement of Basal Bone:
Madibular fractures were classified based on involvement of the basal bone by Rowe and Killey
- Involving the Basal bone: Single unilateral, double unilateral, bilateral, or multiple
- Not involving basal bone: alveolar process fracture
Involving the basal bone
A. Single unilateral fracture
- Fracture dislocation
- No Displacement
- Linear horizontal fracture
- Linear Vertical fracture
- Stellate type fracture
Angle and Body:
- Horizontally favourable or unfourable
- Vertically favourable or unfaourable
- Lesser fragment laterally displaced
- Lesser fragment medially displaced
- Midline fracture
- Oblique fracture
B. Bilateral Fractures:
- Bilateral fracture dislocation of condyle
- Bilateral horizontally and vertically unfavorable fractures
- Bilateral fracture in the canine region
Not Involving the basal bone of mandible
Spiessel Classification of Mandibular Fractures:
Spiessel has classified based on multiple factors as
- Number of fragments (F)
- Location of fracture (L)
- Status of occlusion (O)
- Soft tissue involvement (S)
- Associated fracture (parallel fracture of the facial skeleton) (A)
Classification of fractures by number of fragments and presence of a bone defect (F1 to F4)
- F0: Incomplete fracture
- F1: Single fracture
- F2: Multiple Fracture
- F3: Comminuted Fracture
- F4: Fracture with a bone defect (Loss of Bone)
Classification of Fractures by site (L1 to L8)
- L1: Precanine
- L2: Canine
- L3: Postcanine
- L4: Anlge
- L5: Supra angular
- L6: Condylar process
- L7: Coronoid process
- L8: Alveolar process
Classification of fractures by displacement (O0 to O2)
- O0: No malocclusion
- O1: Malocclusion
- O2: Non-existent occlusion (edentulous mandible)
Classification of fractures by soft tissue involvement (S0 to S4)
- S0: Closed
- S1: Open intraorally
- Open extraorally
- Open intra and extraorally
- Soft tissue defect
Associated fractures (A0 to A6)
- A0: None
- A1: Fractures or loss of teeth
- A2: Nasal Bone
- A3: Zygoma
- A4: Le Fort 1
- A5: Le Fort 2
- A6: Le Fort 3
These are the various types of Classifications of Mandibular fractures which include every aspect such as number of fracture lines, type of fracture, location of fracture Soft tissue involvement, Muscles etc involved, intra oral and extra oral involvement.