What is it?
A jaw fracture is a break in the continuity of the lower jaw bone or of the bones of the midface. In the lower jaw the most common sites are the condyle, the angle in the wisdom tooth region, the body and the point of the chin. Because the teeth sit on this bone, the first thing noticed is most often a change in the bite.
Alongside pain and swelling there may be bruising under the tongue, numbness in the lower lip and at the point of the chin, being unable to open the mouth, a step in the row of teeth, pain that increases on biting and bleeding from the gum margin. With fractures of the condyle on both sides, the front teeth may no longer meet. When the findings are mild, a fracture can be missed.
This is not a condition treated in a dental clinic. The dentist's role is to notice the suspicion of a fracture during the examination and on the panoramic X-ray, to refer you to the right department without delay, and to take part in following up the teeth and the bite once healing is complete. The diagnosis is made with imaging carried out in hospital.
Signs
You will not necessarily have all of these at once.
Why does it happen?
- 01
Blows and falls
A punch to the face, falls and collisions during sport are the most common causes. A blow to the point of the chin can cause a fracture in the condyle, away from where the pain is felt.
- 02
Road and workplace accidents
In high-energy injuries, fractures in more than one bone can be present together and a head injury may go with them. For that reason the assessment is not limited to the jaw alone.
- 03
Local conditions that weaken the bone
An impacted wisdom tooth, a cyst that has grown or another lesion involving the bone can make it easier for a fracture to run along that line. In such cases a smaller strain than expected may be enough.
- 04
Conditions in which the bone is less resistant
A lower jaw thinned by tooth loss in later life, conditions in which bone density is reduced and bone that has had radiotherapy can break more easily. These fractures can appear after a minor knock.
How does it progress?
- Condyle
Fracture of the condyle
Common after blows to the point of the chin. The swelling may not be obvious; the jaw shifts towards the fractured side as you open and mouth opening decreases.
- Angle and body
Fracture of the body and angle of the lower jaw
It most often runs through the wisdom tooth region. A step in the row of teeth, bruising under the tongue and numbness in the lower lip are the expected findings.
- Chin
Symphysis fracture
It is caused by a direct blow and often goes together with a fracture of the condyle on the opposite side. That is why, when one fracture is found, the other regions are examined as well.
- Midface
Upper jaw and cheekbone fracture
The whole upper row of teeth moving as one, swelling around the eye, double vision and a nosebleed may be seen. Findings involving the eye mean the assessment must not be delayed.
How is it treated?
The place to go with this is a hospital emergency department; the assessment is carried out by oral and maxillofacial surgery, or by plastic, reconstructive and aesthetic surgery. There you can expect an examination, a CT scan if it is needed, and observation for head injury. In high-energy injuries the general condition and the airway are assessed first.
In fractures where the pieces are in place and not moving, monitoring with a soft diet and rest for the jaw may be chosen. In displaced fractures, fixation with plates and screws, or holding the jaws together for a set period with wires and elastics, comes into play; which one is suitable is determined by the site and the type of the fracture. The decision and the procedure belong to the surgical team.
Time is decisive here: if the bone heals in the wrong position, a lasting bite problem becomes established and putting it right afterwards is a bigger undertaking. Pain easing does not mean the fracture has healed. The dental clinic's role in this process is to notice the suspicion, to speed up the referral by taking the X-ray that is needed, and to take part in following up the teeth, the fillings and the bite after healing.
- Your teeth not meeting as they did after a blow
- Numbness in the lower lip and at the point of the chin
- Bruising under the tongue and being unable to open your mouth
- Loss of consciousness, being sick, double vision or bleeding that will not stop
How is it prevented?
- Wear a mouthguard for contact sports, and a helmet when cycling or riding a motorbike.
- Always wear your seatbelt when you are in a vehicle.
- If an impacted tooth or a cyst has been found, keep to the follow-up; the bone can stay weak along that line.
- Even if your pain has eased after a blow, do not put off the assessment if your bite has changed.
Frequently asked questions
- Can you tell whether there is a fracture without an X-ray?
- The examination gives strong clues; a change in the bite, a step in the row of teeth, numbness in the lip and bruising under the tongue are some of them. But the site of the fracture, its direction and the position of the pieces cannot be worked out without imaging. So where there is a suspicion, the assessment is completed in hospital with the right imaging.
- My pain has eased, should I still be seen?
- Yes. Pain easing does not show that there is no fracture or that it has healed; with fractures of the condyle in particular, swelling and pain can stay limited. If the bone heals in the wrong position your bite can be permanently disturbed, and putting it right later is a bigger undertaking. If your bite has changed, the assessment should not be postponed.
- Is a jaw fracture treated in a dental clinic?
- No. Treatment of the fracture is carried out in hospital, in oral and maxillofacial surgery or in plastic, reconstructive and aesthetic surgery. The dental clinic's job in this condition is to notice the suspicion of a fracture and to refer you without delay; once healing is complete, follow-up of the broken teeth, the fillings and the bite can be shared.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.