1. TMJ Pain and Neuropathic Pain in Patients with Temporomandibular Joint Disorders
Dr. Gaetano Meli

2. Symptoms and signs of TMJ disorders
Lateral deviation of the jaw during the mandibular range of motion
Bruxism
Presence of sounds or clicks during the jaw movement
TMJ pain
Neuropathic pain (facial numbness and dysesthesia, headache, toothache and earache)
Reduction of the mandibular opening
Sleep and Psychological disorders
Spine disorders
Okeson JP, Management of Temporomandibular Disorders and Occlusion, 2006

3. Different types of Pain
TMJ pain
When pain is located in the proximity of the temporomandibular joint
Neuropathic pain
Involving greater portion of the orofacial region and it is associated with the onset of sensory deficits of the head (facial paresthesia,headaches, toothache, and ear sounds)
Okeson JP, Management of Temporomandibular Disorders and Occlusion, 2006

4. Neuropathic pain prevalence
Dupont JS, Cranio, 2003

5. Bell classification OF TMD
Masticatory muscle disorders
Temporomandibular joint disorders
Chronic mandibular hypomobility
Growth disorders
Protective
co-contraction
Disc displacement with or without reduction
Ankylosis
Congenital or developmental
bone disorders
Local muscle
soreness
Structural incompatibility of the articular surfaces
Muscle contracture
muscle disorders
Myofascial pain
Inflammatory
conditions
Coronoid impedance
Myospasm
Centrally mediated
myalgia
Okeson- Bell; American academy of orofacial pain, 1996

6. Relationship among pain and MRI findings
Emshoff,

7. “Not all patients have the same reaction to a given stimulus.
They exhibit a differing grade of individual physiological tolerance (Okeson)

8. Temporomandibular joint disorders
Click

9. Temporomandibular joint disorders
Lock

10. Temporomandibular joint disorders
Osteoarthrosis
Subchondral Cyst

12. Which are the causes of the onset of neuropathic pain?
The first mention of a possible clinical relationship among atypical trigeminalgia and temporomandibular disorders was proposed by Costen and dates back to 1934.
He hypothesized that in those patients the disc and/or condyle may directly damage the mandibular nerve and/or its branches by exerting intermittent compression, traction or friction during the jaw opening

14. Anatomy
Netter plates
MRI

15. Prospective case-control analysis without neuropathic pain
Study Group A
16 TMJs with TMJ-D
and neuropathic pain
Control Group B
16 TMJs with TMJ-D
without neuropathic pain
Control Group C
16 healthy TMJs

16. Selection criteria
No significant sex or age differences among the three groups
Clinical diagnosis of TMJ-D achieved by
“Clinical diagnostic criteria for TMD” (Truelove)
Presence of neuropathic pain assesed by
the “neuropathic pain diagnostic questionnaire” (Bouhassira)

17. DN4 Neuropathic Pain Diagnostic Questionnaire.
Interview of the patient
Question 1 : Does the pain have one or more of the following characteristics?
1.Burning yes no
2.Painful cold yes no
3.Electric shocks yes no
Question 2: Is the pain associated with one or more of the following symptoms in the same area?
4.Tingling yes no
5.Pins and needles yes no
6.Numbness yes no
7. Itching yes no
Examination of the patient
Question 3: Is the pain located in an area where the physical examination may reveal one or more of the following characteristics ?
8.Hypoesthesia to touch yes no
9.Hypoesthesia to prick yes no
Question 4: In the painful area, can the pain be caused or increased by?
10.Brushing yes no

18. Disc – mandibular nerve distance
Case
Control
Pedullà, Meli, Garufi et al ; AJNR Am J Neuroradiol. Aug. 2009

19. Healthy subjects Patients with TMJ-D without neuropathic pain
Pedullà, Meli, Garufi et al ; AJNR Am J Neuroradiol. Aug. 2009

20. in the study group A and in the two control groups B and C
Distance of the TMJ disc to the mandibular nerve at the maximum jaw opening
in the study group A and in the two control groups B and C
TMJ
Study Group A
Control Group B
Control Group C 1 10 2 6 8 11 3 4 9 12 5 7 13 14 15 16
Mean Value
6,25
8,18
9,43
Standard Deviation
2,01
1,83
1,82

21. Conclusion
TMJ pain could be correlated to the presence of internal derangement, effusion, osteoarthrosis, and bone marrow edema within the TMJ
TMJ neuropathic pain could be associated to the presence of a mechanical impingement of the TMJ disc on the mandibular nerve fibers

26. Thanks
for your time