Jaw injury claim
Jaw and TMJ injury after a motor accident
A blow to the chin or side of the face can fracture the mandible, injure the temporomandibular joint, displace its disc or change the bite. Clicking and jaw pain are common complaints, but permanent CTP assessment focuses on verified structural injury and lasting mastication, swallowing or facial-function loss after treatment.
Accident mechanism and diagnosis
How can this injury happen in a motor accident?
Chin strike on dashboard or airbag
Force through the chin can fracture the mandible or transmit load into one or both TMJs.
Side facial impact
Window, pillar or road contact can produce condylar fracture, joint capsule injury, disc displacement or facial asymmetry.
Forced mouth opening during emergency care
Intubation or surgery can aggravate a traumatised joint; hospital and dental chronology are needed to establish the cause.
The injuries that may actually occur
- mandibular body, angle or condylar fracture
- TMJ disc displacement or internal derangement
- joint capsule sprain, haemarthrosis or post-traumatic arthritis
- malocclusion after fracture or reconstruction
- trigeminal nerve sensory injury associated with jaw trauma
Symptoms and functional effects to document
- restricted mouth opening or deviation
- locking, catching or painful clicking
- difficulty chewing firm or mixed-texture food
- bite change, jaw fatigue or facial asymmetry
- numb lower lip or chin after fracture or surgery
Urgent health warning
An unstable jaw, airway or swallowing difficulty, uncontrolled bleeding, severe bite change or facial numbness with fracture signs requires urgent assessment.
Medical evidence
What tests and findings matter?
The useful record distinguishes a joint or fracture diagnosis from pain alone and measures the permanent effect on opening, occlusion, chewing and diet after dental or maxillofacial treatment.
| Test or record | What it can establish | What it cannot establish alone |
|---|---|---|
| Maxillofacial examination | Measures opening, deviation, occlusion, joint tenderness, locking and facial symmetry. | Tenderness or clicking alone does not quantify permanent mastication loss. |
| CT, OPG or dental X-ray | Shows fracture, healing, fixation, condylar position and dental support. | A healed fracture line or hardware does not automatically produce WPI. |
| TMJ MRI | May show disc position, joint effusion or internal derangement where clinically indicated. | Disc displacement can be asymptomatic and must match examination and function. |
| Diet and bite assessment | Documents permanent food restriction, chewing efficiency and malocclusion after treatment. | A temporary post-operative soft diet does not establish permanent impairment. |
A separate legal classification
Threshold injury is not the same as WPI
A mandibular fracture, verified joint derangement or nerve injury may be more than a soft tissue threshold injury. Jaw pain or capsule sprain without qualifying structural or nerve injury may remain threshold. Classification and WPI are separate decisions.
A non-threshold classification does not set a WPI percentage. Conversely, a low or zero WPI assessment does not necessarily decide the threshold-injury classification. Physical and psychiatric WPI are assessed separately and cannot be combined to determine whether impairment is greater than 10%.
Motor Accident Guidelines Part 6
How is permanent impairment assessed?
Part 6 adopts AMA4 Chapter 9 for mastication and deglutition. Clauses 6.194-6.198 are particularly relevant where teeth, prostheses or facial structure are also involved. The assessor identifies the lasting functional pathway rather than assigning a fixed percentage to a fracture, arthroscopy or joint diagnosis.
| Assessment issue | CTP method | Important limit |
|---|---|---|
| Permanent chewing restriction | Use the AMA4 Chapter 9 mastication/deglutition method and Table 6 where supported by permanent dietary restriction. | Clause 6.197 corrects the first Table 6 category to 0-19%; a claimant cannot choose a figure from symptoms. |
| Facial structural change | Assess permanent cosmetic or structural loss under the applicable facial method. | Do not count the same malocclusion or chewing loss again under a second heading. |
| Associated nerve injury | Use the applicable cranial or peripheral nerve method where objective sensory or motor loss remains. | Numbness without reproducible distribution and diagnosis is not a separate automatic rating. |
What may result in 0% or no assessable WPI?
- clicking or tenderness with normal function and unrestricted diet
- a healed fracture with restored occlusion and mouth opening
- temporary post-operative diet or muscle spasm
- MRI disc change without permanent functional consequence
What may support a higher assessment if verified?
- persistent verified restriction of opening with functional eating limits
- permanent malocclusion or structural deformity
- documented long-term dietary restriction
- distinct objective nerve, dental or facial impairment after overlap is removed
Combination and overlap rules
- Dental, jaw and facial methods may overlap; the same chewing or appearance loss cannot be rated twice.
- Scarring from jaw surgery is assessed by the skin/facial method only if it creates a distinct permanent impairment.
- Pain is included in the applicable body-system method and has no separate Chapter 15 WPI.
What does not establish impairment by itself?
- jaw clicking alone
- pain on chewing without measured or documented restriction
- TMJ MRI change without matching function
- the fact that fixation or arthroscopy occurred
Crash-specific examples
Condylar fracture with restored bite
The fracture may be non-threshold, but if opening, occlusion and diet return to normal after treatment, it may leave little or no assessable WPI.
TMJ derangement with lasting food restriction
MRI supports the diagnosis, while serial opening measurements, specialist opinion and permanent dietary evidence establish the functional consequence.
Claim file preparation
Evidence checklist
Assessment source
Jaw and mastication assessment under NSW CTP
Assessment source: Motor Accident Guidelines Part 6, clauses 6.177-6.179 and 6.194-6.198; AMA4 Chapter 9 mastication and deglutition, including Table 6 (page 231).
Threshold injury: A fracture, structural joint injury or objective nerve injury may be non-threshold; pain and soft tissue findings require separate classification.
What the assessor checks
- objective jaw or joint diagnosis
- permanent mastication and dietary effect
- occlusion and structural integrity
- distinct dental or nerve consequences
What does not establish the result by itself
- clicking
- pain alone
- temporary diet
- surgery or imaging alone
Official sources
Related NSW CTP guides
Free claim check
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Frequently asked questions
- Does TMJ clicking produce WPI?
- Not by itself. The assessment needs a supported diagnosis and permanent functional effect on mastication, swallowing or related facial function.
- Is a jaw fracture automatically non-threshold?
- A verified fracture is generally more than a soft tissue injury, but the precise statutory classification should be applied to the medical evidence.
- Does jaw surgery create a fixed WPI?
- No. The result is assessed as it presents after treatment, using the applicable functional method.
- What proves permanent dietary restriction?
- Consistent maxillofacial or dental findings, treatment outcome and a documented long-term inability to manage particular food textures.
- Can jaw numbness be assessed separately?
- Potentially, where an objective nerve injury creates a distinct permanent deficit and is not already counted elsewhere.