Temporomandibular joint dislocation is dealt with in the separate article Mandibular Dislocation.
When a blow to the mandible causes a fracture there are often other fractures too and these must be sought:
- Trauma to one side often produces an ipsilateral body fracture and a contralateral subcondylar fracture.
- A heavy blow to the symphysis produces a symphyseal fracture and bilateral subcondylar fractures.
- It is also important to exclude damage to the cervical spine and to ascertain that the airway is not compromised.
The most commonly fractured sites are:
- Body (29%)
- Condyle (26%)
- Angle (25%)
- Symphysis (17%)
- Ramus (4%)
- Coracoid (1%)
The average number of fractures in a mandible is between 1.5 and 1.8 with 10% of patients having more than 2 fractures.
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The cause of the injury may be road traffic accidents, assault, falls, industrial injuries or sports injuries but the relative number of each varies considerably between countries and areas.
- Under the age of 25, dental trauma accounts for more lost teeth than caries or gum disease.
- In terms of violence, young males are most at risk with alcohol an aggravating factor.
- Women and children are much less at risk, but can be from domestic violence.
- There is a male preponderance of about 3:1 in adults and 3:2 in children.
The history may indicate the site and direction of force, the possible presence of other injuries, especially to the neck, and other relevant features such as loss of consciousness and head injury.
- Note any abnormality in facial contour and shape of the mandible as well as tenderness, swelling, redness, lacerations or haematoma.
- Check movements of the mandible and malocclusion.
- Loose and fractured teeth should be evaluated and counted.
- If teeth are missing, and unaccounted for, consider CXR in case of inhalation.
If the mucosa is intact, clinical findings may be limited to bruising. If the mandibular branch of the trigeminal nerve (the inferior alveolar or mental nerve) has been injured, there will be paraesthesia or anaesthesia of the chin. Documenting this and any damage to the marginal mandibular nerve branch of the facial nerve is important before surgery.
Spasm of the muscles of mastication can produce trismus that impairs a proper oral examination. The pull of muscles may reduce or distract a fracture. Facial oedema, erythema, and pain may also occur.
Some fractures can result in the posterior displacement of the tongue and lead to airway compromise. The airway obstruction requires immediate attention.
- There are a number of views of plain X-rays that give a good picture of the mandible, teeth and their roots. A panoramic view is especially useful.
- CXR may also be required if teeth are unaccounted for.
- CT scanning gives excellent detail and is very helpful in planning management.
A patient with teeth that may be loose or knocked out requires immediate referral to a dentist if other injuries do not override that consideration.
NB: fractures in the region of the teeth must be considered as compound fractures, as there is a risk of infection from the oral cavity. An open laceration may overlie a compound fracture.
A conservative approach is permissible if there is little or no displacement.
- This may be acceptable for children with a greenstick fracture or the elderly edentulous patient with minimal displacement.
- Support to the jaw may relieve discomfort.
- Chewing should be minimised or avoided with a liquid or puréed diet.
A surgical approach is often advocated nowadays where a conservative line may have been acceptable before.
- Closed reduction may be achieved or open reduction permits direct inspection and mechanisms to stabilise the fracture.
- Wire tends to be reserved for children and titanium plates and screw fixation are often used in adults.
- Mandibulo-maxillary fixation (MMF) may be required.
- Children have MMF for 4 weeks, adults for 6 weeks, but the elderly may require 8 weeks.
- Patients with condylar fractures must have MMF removed by 2 weeks, and aggressive physiotherapy is required to prevent ankylosis.
- MMF requires tube feeding of a liquid or puréed diet and attention to oral hygiene.
- Implants may be used to correct deformity. Teeth on the fracture line rarely need removal.
Preoperative antibiotics reduce the frequency of infection considerably.
Complications may be related to the trauma to the mandible or related trauma.
- Delay in fixing the fractured mandible increases the risk of complications, but neurological complications or other problems such as airway compromise may make this inevitable.
- If there is bilateral fracture of the body of mandible, parasymphyseal, or condylar fractures, there is risk of airways' impairment as the muscular action pulls the distal mandibular segment backwards, allowing the tongue to obstruct the oropharynx.
- There may also be nerve damage.
- In neuropraxia, function takes 4 to 6 weeks to return, but in neurotmesis, function takes around 18 months to return, if it returns.
- Infection increases complications including malunion or nonunion.
- Ankylosis can result in poor ability to open the mouth.
- The psychological implications of facial trauma are such that the risk of post-traumatic stress disorder is increased in this condition.
- Mouthguards in sport reduce the incidence of trauma to the mandible.
- They do not have an adverse effect on aerobic performance.
- The mouthguard needs to be appropriate to the individual and to the sport.
Fractures of the mandible were described in ancient Egypt around 1650 BC. Hippocrates described facial injuries around 400 BC.
- The problem of occlusion was addressed in Italy in 1180, but fixation of the fractured mandible was first recorded in 1492.
- The First and Second World Wars saw improvements in radiology and management of airways and other injuries.
- The advent of CT scanning allowed a much more detailed picture of the injured area to assess injury and plan treatment.
- Better anaesthetic and supportive techniques have permitted a more aggressive approach to reconstruction.
Further reading & references
- Caminiti MF, Weinberg S. Chronic Mandibular Dislocation: The Role Of Non-Surgical and Surgical Treatment
- Chao MT et al; Facial Trauma, Sports-Related Injuries, eMedicine, Sep 2010
- Faust RA, Younes AA; Mandible fracture in children, eMedicine, Jun 2009
- Barrera JE, Batuello SG; Mandibular angle fractures, eMedicine, Nov 2008
- Gassner R, Tuli T, Hachl O, et al; Cranio-maxillofacial trauma: a 10 year review of 9,543 cases with 21,067 injuries. J Craniomaxillofac Surg. 2003 Feb;31(1):51-61.
- Gassner R, Tuli T, Emshoff R, et al; Mountainbiking--a dangerous sport: comparison with bicycling on oral and maxillofacial trauma. Int J Oral Maxillofac Surg. 1999 Jun;28(3):188-91.
- Hill CM, Burford K, Martin A, et al; A one-year review of maxillofacial sports injuries treated at an accident and emergency department. Br J Oral Maxillofac Surg. 1998 Feb;36(1):44-7.
- Chang EW, Lam SM, Karen M, et al; Sliding genioplasty for correction of chin abnormalities. Arch Facial Plast Surg. 2001 Jan-Mar;3(1):8-15.
- Hoenig JF; Sliding osteotomy genioplasty for facial aesthetic balance: 10 years of experience. Aesthetic Plast Surg. 2007 Jul-Aug;31(4):384-91.
- Berg S, Pape HD; Teeth in the fracture line. Int J Oral Maxillofac Surg. 1992 Jun;21(3):145-6.
- Glynn SM, Asarnow JR, Asarnow R, et al; The development of acute post-traumatic stress disorder after orofacial injury: a prospective study in a large urban hospital. J Oral Maxillofac Surg. 2003 Jul;61(7):785-92.
- Glynn SM, Shetty V, Elliot-Brown K, et al; Chronic posttraumatic stress disorder after facial injury: a 1-year prospective cohort study. J Trauma. 2007 Feb;62(2):410-8; discussion 418.
- Patrick DG, van Noort R, Found MS; Scale of protection and the various types of sports mouthguard. Br J Sports Med. 2005 May;39(5):278-81.
- Knapik JJ, Marshall SW, Lee RB, et al; Mouthguards in sport activities : history, physical properties and injury prevention effectiveness. Sports Med. 2007;37(2):117-44.
- Kececi AD, Cetin C, Eroglu E, et al; Do custom-made mouth guards have negative effects on aerobic performance capacity of athletes? Dent Traumatol. 2005 Oct;21(5):276-80.
- Choy MM; Children, sports injuries & mouthguards. Hawaii Dent J. 2006 Sep-Oct;37(5):11-3.
- Lieger O, von Arx T; Orofacial/cerebral injuries and the use of mouthguards by professional athletes in Switzerland. Dent Traumatol. 2006 Feb;22(1):1-6.
- Tawfilis AR, Byrne P; Facial trauma, mandibular fractures, eMedicine, Jun 2009
|Original Author: Dr Hayley Willacy||Current Version: Dr Hayley Willacy|
|Last Checked: 16/07/2010||Document ID: 2432 Version: 21||© EMIS|
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