Mandibular Fractures

Question 1

What muscles elevate the mandible?

Answer 1

• temporalis
• masseter
• medial pterygoid

Question 2

What muscles depress the mandible?

Answer 2

• lateral pterygoid
• geniohyoid
• anterior belly of digastric

Question 3

What are some clinical signs & symptoms of mandibular fracture?

Answer 3

• pain, swelling, limitation of function
• occlusal derangement
• numbness of lower lip
• loose or mobile teeth
• bleeding
• AOB
• facial asymmetry
• mandibular deviation on opening to opposite side of fracture

Question 4

What might edentulous patients experience due to mandibular fracture?

Answer 4

Sublingual hematoma [FoM bleeding]

Question 5

What are the 7 classifications of mandibular fractures?

Answer 5

1. Involvement of surrounding tissue
2. Number of fractures
3. Side of fracture
4. Site of the fracture
5. Direction of fracture line
6. Specific Fractures
7. Displacement of the Fracture

Question 6

How are mandibular fractures classified in reference to involvement of surrounding tissues?

Answer 6

Simple = only involves bone [STs intact]

Compound = surrounding soft tissue lacerated or bone exposed

Comminuted = bone is broken into multiple small pieces

Question 7

What type of injuries are comminuted fractures?

Answer 7

Gunshot wounds

Question 8

How are mandibular fractures classified in reference to number of fractures?

Answer 8

1. Single
2. Double
3. Multiple

Question 9

How are mandibular fractures classified in reference to side of fracture?

Answer 9

Unilateral
Bilateral

Question 10

How are mandibular fractures classified in reference to site of fracture?

Answer 10

• angle of mandible
• subcondylar
• parasymphyseal
• body
• ramus
• coronoid
• condylar fracture
• alveolar process

Question 11

How are mandibular fractures classified in reference to direction of fracture line?

Answer 11

Favourable = fracture line minimises risk of displacement

Unfavourable = fracture line encourages displacement

Question 12

How are mandibular fractures classified in reference to specific fractures?

Answer 12

• green stick fractures
• pathological fracture

Question 13

What is a green stick fracture?

Answer 13

commonly occurs in children due to their softer, more flexible bones
- occur when one side of the bone bends, causing it to partially fracture, while the other side remains intact
- “greenstick” is derived from the analogy of trying to break a young, green stick from a tree, where the stick bends but does not break completely

Question 14

How are mandibular fractures classified in reference to displacement of the fracture?

Answer 14

• displaced
• not displaced

Question 15

What factors can cause displacement of a mandibular fracture?

Answer 15

• direction of fracture line
• opposing occlusion
• magnitude of injury force
• mechanism of injury
• status of soft tissues [if intact, displacement less likely]
• other associated fractures

Question 16

How are mandibular fractures managed?

Answer 16

• clinical exam
• radiographic assessment
• treatment

Question 17

How is radiographic assessment of mandibular fractures carried out?

Answer 17

1. Initial OPT & PA mandible
2. Other views = lower occlusal, lateral oblique, CBCT

Question 18

How are mandibular fractures treated?

Answer 18

1. ALWAYS control of pain & infection [analgesics & antibiotics]
2. Decide if pt requires surgical treatment or fixation without surgery

Question 19

What are the two basic principles of surgical treatment of a mandibular fracture?

Answer 19

1. Reduction = put fractured sections into correct anatomical position
2. Fixation = keep fracture in displaced position

Question 20

Displaced or mobile mandibular fractures MUST undergo fixation, what are the two methods of this treatment?

Answer 20

Close Reduction & Fixation
- fracture not opened surgically, dependent on pts occlusion to guide fracture into correct alignment
- involves wiring mouth shut

Open Reduction & Internal Fixation
- expose bony edges surgically, flap raised & reduce them directly with vision
- fixed in place with titanium plates & screws

Question 21

What medical condition contraindicates mouth wiring procedures?

Answer 21

Epilepsy
- if patient vomits during seizure they will choke

Question 22

Give examples of specific surgical approaches that can be used to treat mandibular fractures?

Answer 22

• retro-mandibular approach
• raisdon approach
• preauricular approach
• bi-coronal flap
• endoscopic reduction & fixation