TOPIC: TRAUMATIC INJURIES TO THE MAXILLOFACIAL REGION
🌟 IMPORTANT POINTS TO REMEMBER
🔸Factors that significantly increase susceptibility to dental injury are postnormal occlusion, an overjet exceeding 4 mm, short upper lip, incompetent lips and mouth breathing.
🔸Fractures Of Alveolar Process: The labial plate is most often fractured than palatal plate; occlusion has been changed.
🔸Lateral extraoral radiographs best demonstrate the location of the fracture.
🔸Simple Fracture: Single fracture line that does not communicate with the exterior.
🔸Compound Fracture: These fractures have a communication with the external environment.
🔸Greenstick Fracture: In children and involves incomplete loss of continuity of the bone.
🔸Comminuted Fractures: Exhibit multiple fragmentation of the bone at one fracture site.
🔸Complex Or Complicated Fracture: This type of injury implies damage to structures adjacent to the bone, such as
major vessels, nerves or joint structures.
🔸Telescoped Or Impacted Fracture: One bony fragment is forcibly driven into the other.
🔸Indirect Fracture: Indirect fractures arise at a point distant from the site of the fracturing force.
🔸Pathologic Fracture: Pathologic fracture is said to occur when a fracture results from normal function or minimal trauma in a bone weakened by pathology.
🔸Nondisplaced Fracture: It is a linear fracture.
🔸Deviated Fracture: Simple angulation of the condylar process.
🔸Displaced Fracture: In displaced fractures the articular surface of the condyle remains within the glenoid fossa and does not herniate through the joint capsule.
🔸Dislocated Fracture: A dislocation occurs when the head of the condyle moves in such a way that it no longer articulates with the glenoid fossa.
🔸Clinical Features Of Mandibular Fracture: Changes in the occlusion, anaesthesia, paraesthesia or dysaesthesia of lower lip, abnormal mandibular movement, change in facial contour and mandibular arch form, lacerations, haematoma and ecchymosis.
🔸Radiological Feature Of Mandibular Fracture: The margins of the fractures usually appear as sharply defined radiolucent lines of separation that are confined to the structure of the mandible. Displacement of the fracture results in irregularity in occlusal plane or cortical discontinuity or ‘step’. Increased radio-opacity at the fractured site suggests overriding of the fracture segments.
🔸Trauma To TMJ Region: Bleeding from external auditory canal, facial asymmetry, malocclusion and deviation of the mandible.
🔸Le Fort I: Fracture line extends backward from the lateral margin of the anterior nasal aperture below the zygomatic buttress to cross the lower third of the pterygoid lamina. Fracture also passes along the lateral wall of the nose and the lower third of nasal septum to join the lateral fracture behind the tuberosity. There is slight swelling of the upper lip, ecchymosis, midline splitting of palate, soft-tissue laceration and ‘cracked-pot’ sound of the upper teeth.
🔸Le Fort II: This fracture runs from the thin middle area of the nasal bones down to either side crossing the frontal processes of maxilla into the medial wall of each orbit. Within each orbit, the fracture line crosses the lacrimal bone behind the lacrimal sac before turning forward to cross the infraorbital margin slightly medial to or through the infraorbital foramen. The fracture now extends downwards and backwards across the lateral wall of the antrum below zygomaticomaxillary suture and divides the pterygoid laminae about halfway up. Oedema of middle third of face is known as ‘ballooning’ or ‘moon face’. Bilateral circumorbital oedema and ecchymosed bilateral subconjunctival haemorrhage.
🔸Le Fort III: The fracture runs from near the frontonasal suture transversely, parallel with the base of the skull and involves the full depth of the ethmoid bone, including the cribriform plate. Within the orbit, the fracture passes below the optic foramen into the posterior limit of the inferior orbital fissure. Gross oedema of face, ‘ballooning’ and ‘Panda faces’ occur within 24–48 h of injury. There may be bilateral circumorbital/periorbital ecchymosis and gross oedema ‘raccoon eyes’.
🔸ZMC Fracture: Flattening of the cheek, enophthalmos, periorbital haematoma, subconjunctival haemorrhage, lowering of pupil level and step deformity of infraorbital margin.
📣 CLASSIFICATION OF TMJ REGION
💠Fracture Lindahl in 1977 classified fracture based on several factors including the following:
🔺Level Of Condylar Fracture:
- Condylar head/intracapsular fracture: It can be vertical fracture, compression fracture or comminuted fracture.
- Condylar neck/extracapsular fracture.
- Subcondylar fracture.
🔺Relationship Of Condylar Fragment With Mandibular Fragment:
- Non-displaced
- Deviated
- Displacement with medial or lateral overlap
- Displacement with anterior or posterior overlaps
- No contact between the fractured segments
🔺Relationship between condylar head and glenoid fossa:
- Non-displaced
- Displacement
- Dislocation
📣 ZYGOMATICOMAXILLARY COMPLEX FRACTURE
💠 CLASSIFICATION
🔺Class I: Fracture of zygomatic bone with minimum or no displacement.
🔺Class II: Fracture of zygomatic bone with displacement.
- Type A: Rotation around a vertical axis.
Inversion of the orbital ring, eversion of the orbital ring.
- Type B: Rotation around a longitudinal axis.
Medial displacement of frontal process. Lateral displacement of frontal process.
🔺Class III: En bloc displacement of the bone.
- Medial displacement.
- Inferior displacement.
- Lateral displacement.
🔺Class IV: Comminution of the zygomatic bone.
🔺Class V: Fracture of zygomatic arch alone.
📌 MULTIPLE CHOICE QUESTIONS (MCQs)
💡 Incomplete fracture of the enamel without loss of tooth substance is termed as
- Laceration
- Enamel infarction
- Crown fracture
- Complicated fracture
Answer: 2
💡 Complete displacement of the tooth out of its socket is called
- Extrusion
- Intrusion
- Concussion
- Avulsion
Answer: 4
💡 The floor of the mouth can be best visualised by an occlusal film with the beam directed from
- Submandibular region
- Submental region
- Little’s area
- Maxillary premolars
Answer: 2
💡 The extraoral radiograph which best demonstrates alveolar fracture is
- PA view
- AP view
- Lateral view
- IOPA
Answer : 3
💡 Fry et al. classified mandibular fracture into four types depending on
- Area
- Direction
- Region
- None of the above
Answer: 2
💡 Numbness in the distribution of inferior alveolar nerve after trauma is pathognomonic feature of a fracture
- Mesial to mandibular foramen
- Distal to mandibular foramen
- Symphysis of the mandible
- Angle of the mandible
Answer: 2
💡 Medial displacement of condyle and condylar neck fracture can be ideally detected in
- Lateral oblique radiograph
- Posteroanterior radiograph
- Reverse Towne view
- None of the above
Answer : 3
💡 According to Lindahl the displacement and dislocation type of TMJ fractures are based on
- Level of condylar fracture
- Relationship of condylar fragment with mandibular fragment
- Relationship between condylar head and glenoid fossa
- All of the above
Answer: 3
💡 Floating fractures refers to
- Le Forte I
- Le forte II
- Le Forte III
- NOE fracture
Answer: 1
💡 Ballooning or moon face refers to the oedema of
- Upper third of face
- Middle third of face
- Lower third of face
- None of the above
Answer: 2
💡 Bilateral circumorbital or periorbital ecchymosis and gross oedema refer to
- Hooding of eyes
- Panda face
- Enophthalmos
- Raccoon eyes
Answer: 4