Broken jaw in dogs – symptoms, treatment and healing

Overview

Upper and lower jaw fractures

The lower jaw consists of separate bony halves joined centrally by a fibrous connection called the symphysis. A fracture may be an incomplete crack or a comminuted injury with several bone fragments. Tooth roots, nerves and blood vessels pass within or near the jaw. Choosing a repair method therefore involves more than supporting bone.

A central aim of jaw fracture treatment is restoring a correct bite and normal function. Upper jaw fractures can be supported with wire, sutures or an intraoral splint, for example. Repairing a lower jaw fracture can be more challenging.

In a group of 94 dogs younger than 1 year with facial and skull trauma, 52, or 55.3%, had an upper jaw fracture. Thirty-nine dogs, or 41.5%, had a fracture in the lower jaw's molar region. These are findings in trauma patients, rather than disease risks for all puppies.

A young dog with facial and skull trauma can have several fractures. In the 94-dog group, the mean number of fractured bones or separately assessed bony regions was 8.8 per dog, with a standard deviation of 3.1. The maximum number of affected regions was 37. Only 12 dogs, or 12.7%, had a single fractured bone or region. A visible jaw break may therefore be only part of the overall facial injury.

Causes

A traumatic fracture

Breaking a healthy jawbone generally requires a strong impact. Injuries occur in car accidents, animal fights, entrapment in fencing and falls onto a hard surface. Treatment planning therefore also establishes how the accident happened.

Among the 94 young facial and skull trauma patients studied, an animal bite caused 67 cases, or 71.2%. This bite-related distribution concerns that particular young-dog group.

A jawbone weakened by disease

Severe periodontal disease can weaken lower jawbone enough to cause a pathological fracture. A tumour can also weaken bone. A jaw fracture may sometimes become apparent during tooth extraction. Poor-quality bone slows healing of this type of fracture.

Risk factors

Pathological fractures are more common in older than younger animals. In small dogs, the lower first molar is larger relative to jaw height than in large dogs. Bone structure and dental disease can therefore contribute to weakness at the fracture site.

In young dogs, developing permanent teeth may be close to the fracture. Treatment of a growing jaw also considers damage to these teeth. The 94 young facial and skull trauma patients studied had a mean age of 4.2 months and standard deviation of 2.5 months. Breed-specific disease risk cannot be inferred from such a selected trauma patient group.

Typical symptoms

A jaw fracture can alter jaw position and make eating difficult. Signs at home or at the accident scene may include:

• Reluctance to take food or chew.
• Bleeding from the mouth.
• A crooked jaw or altered bite alignment.
• Wounds, swelling and tenderness around the mouth.
• A mouth that remains open.
• Increased drooling, sometimes blood-stained.

With bilateral lower jaw fractures, the mouth may hang open particularly noticeably. The lower jaw's midline usually shifts towards the fractured side. Jaw joint dislocation can cause similar eating difficulty and bite changes. Distinguishing them therefore requires mouth and jaw examination.

With jaw joint dislocation, the lower jaw's midline usually shifts away from the injured side. This difference helps guide your vet's investigations.

Complications and consequences

An abnormal bite and delayed healing

Jaw fracture complications include malocclusion, infection, delayed union and non-union. An abnormal bite can injure oral soft tissues, wear teeth and make eating difficult. It can also cause jaw joint dysfunction.

In the young-dog group, 81 dogs returned for follow-up examination. Complications were found in 58 dogs, or 71.6% of those followed. Among patients with complications, 32, or 55.2%, had malocclusion. This does not mean more than half of all dogs with jaw fractures had an abnormal bite.

Among young dogs with complications, 23, or 39.7%, had non-vital teeth. Tooth structure defects occurred in 21, or 36.2%, of this group. Jaw joint abnormalities developed in 6 dogs, or 10.3% of patients with complications. These included osteoarthritis and stiffening around the joint restricting movement. Such consequences may be detected only during later follow-up.

Diagnosis at the vet

General condition first, then the jaw

The whole dog is examined before attention is restricted to the visible jaw injury. Concurrent chest injuries can include lung bruising, pneumothorax or a diaphragmatic hernia. X-rays of other body regions may be needed before definitive jaw treatment.

Examining a painful mouth may require sedation or anaesthesia. Your vet assesses the teeth and their relationship to the fracture line. The mucosa covering bone at the fracture may be broken, making it an open fracture.

X-rays and CT

X-rays confirm a fracture and help plan treatment. Computed tomography, or CT, defines the extent of complex facial injuries more precisely. An injury at the front of the jaw can be accompanied by a fracture of the more distant jaw joint surface. Examination is therefore not restricted to the visible injury at the front.

A missing tooth may have been lost completely or fractured with root portions remaining beneath the gum. Dental X-rays or CT can distinguish these possibilities. The jaw joint is also checked in a lower jaw fracture patient.

In the young facial and skull trauma group, 30 dogs, or 32.0%, had other concurrent injuries. Eye injuries occurred in 19 dogs, or 20.2%. The jaw joint surface was fractured in 34 dogs, or 36.2%. These figures describe injuries in the same young trauma patients, and injuries could coexist.

Treatment

Supporting the fracture

Your vet selects fixation according to fracture stability, location and surrounding tissues. A mild, stable fracture may not require surgical repair. Surgery is usually recommended for unstable, comminuted or bilateral lower jaw fractures.

An intraoral splint attached to the teeth and wire can support a lower jaw fracture. Another option is a bone plate and screws holding fragments in position. In external fixation, pins inserted into bone connect to a supporting structure outside the skin. These are veterinary repairs rather than supports fitted at home.

Tooth roots and blood vessel and nerve canals limit safe positions for metal fixation. An intraoral plastic splint can anchor to stable teeth on both sides of the fracture line. A fracture at or behind diseased back teeth may be harder to support. Reasons include thinner bone and lack of suitable anchoring teeth.

Tears of the tongue, lips and oral mucosa can be closed with absorbable sutures. Oral soft tissues have a rich blood supply and generally heal quickly.

Pain, nutrition and monitoring fixation

Fracture repair includes pain relief prescribed by your vet. An open fracture may also require antibiotics. A feeding tube can maintain nutrition during healing.

Soft food places less strain on healing bone and oral tissues than hard food. Intraoral support is often removed at 6–8 weeks. Imaging monitors healing before deciding to remove fixation.

Outlook and additional treatment

The prognosis is generally excellent without complications. A severe pathological fracture around diseased back teeth can nevertheless have a guarded outlook. Greater fragmentation and displacement in young dogs are associated with poorer bone healing.

Among the 81 young facial and skull trauma patients followed, 45, or 55.6%, needed additional treatment. Of those receiving further treatment, 35 dogs, or 77.7%, underwent tooth extractions. These figures do not compare randomised treatment methods.

Follow-up in the young-dog group ranged from 1 week to 17 months after the first visit. It included conscious oral examinations and repeat CT in some dogs. Further care may also involve root canal treatment or removal of damaged tissue. Healing assessment therefore considers bite alignment and teeth as well as bone.

Prevention

Regular brushing of healthy teeth helps prevent tartar formation. Getting a dog used to dental care starts in puppyhood. Bad breath, red gums or difficulty chewing can suggest gingivitis. Oral disease is treated before inflammation that weakens bone progresses.

Avoiding drops forms part of handling a small dog safely. A child holds the dog while sitting on the floor. During jaw fracture healing, prevent chewing bones and toys and rough play with other animals.

In a car, secure your dog on the rear seat in a seat-belt harness or an appropriately sized crate secured to the vehicle structure. A collar is not used to restrain a dog in a car.

Important for dog owners

Food, oral hygiene and activity

Follow discharge instructions for soft food or prescribed tube feeding. Food debris can collect around an intraoral splint and wires. Cleaning is carried out as taught by your vet. Food collecting beneath an intraoral plastic splint predisposes to gingivitis.

An external bone fixation device may need regular cleaning and dressing changes. Around an external muzzle support, monitor skin irritation and food accumulation.

Panting and vomiting need particular attention

Dogs regulate temperature by panting. A support restricting mouth opening can prevent panting and rapidly raise body temperature. Avoid exertion and go outside at the coolest times. Fixation joining the upper and lower jaws increases aspiration risk if a dog vomits. Report vomiting to the treating vet immediately.

Frequently asked questions

Can a dog break their jaw without a major accident?

Severe periodontal disease or a tumour can weaken jawbone and cause a pathological fracture. Such fractures occur predominantly in older animals. A sudden bite change or pain when eating is therefore investigated even if you have not seen a fall, bite or another obvious injury.

How long does a jaw fracture take to heal?

A supporting appliance can often be removed at around 6–8 weeks. The decision nevertheless depends on X-ray evidence of healing. Bone weakened by periodontal disease can heal more slowly. Removal of support and increased chewing are therefore timed according to your dog's own reassessment results.

Does every jaw fracture need surgery?

A stable, only mildly damaged jaw may not need surgery. Unstable, comminuted and bilateral lower jaw fractures are, however, usually repaired surgically. Your vet selects the method using bite alignment, imaging and the dog's overall condition.

Can a dog with a broken jaw eat independently?

Once a fracture is supported, a dog can often eat soft food. Some dogs need a feeding tube to maintain nutrition. Food and feeding method are tailored to restricted mouth movement. At discharge, owners are taught how to use and care for any feeding tube.

Why are teeth examined after fracture repair?

In a growing dog, trauma can also damage developing permanent teeth. Follow-up of young facial and skull trauma patients identified non-vital teeth and tooth structure abnormalities. Fracture repair therefore does not end oral monitoring. Malocclusion may require later tooth repair or extraction.