Multimodal Assessment of Sensory Processing and Brain Features in Patients With Chronic Orofacial Pain

Chronic orofacial pain disorders may present localized in the mouth such as with persistent
dentoalveolar pain disorder (PDAP) or widespread in the head/face/jaw such as with
temporomandibular disorders (TMD). PDAP pain manifests in a tooth that usually underwent root
canal treatment or in the site formally occupied by such tooth, while TMD pain is usually
reported over the preauricular area, jaws and temples. These commonly comorbid disorders have
a significant impact on the individual and society. Their mechanisms are poorly understood
with evidence suggesting deficient pain modulation and abnormal brain features. PDAP and TMD
patients, when compared to controls, have abnormal sensory/pain processing as well as brain
structural and functional differences.

This proposal will investigate pain modulatory mechanisms and brain functional and structural
characteristics using multiple MRI modalities in PDAP patients with and without TMD. All
measures from patients will be compared to painfree controls. This knowledge will support
better understanding of mechanisms involved in PDAP and will support development of
mechanistic-based clinical treatments for the patients the investigators serve. Findings from
these investigations will likely contribute to our understanding of other chronic pain
conditions.

Inclusion Criteria:

1. Age- and handedness-matched painfree controls using frequency matching to maintain
similar group averages:

- No self-report of persistent pain conditions for the last 6 months;

- No diagnosis of PDAP or TMD;

2. PDAP only:

- Fulfilling diagnostic criteria per Nixdorf et al., 20122

- Characteristic dentoalveolar PDAP pain cannot be increased by pressure
provocation from jaw muscle trigger points (referred pain)

3. PDAP with TMD:

- Fulfilling diagnostic criteria for PDAP2 and chronic TMD myalgia per Schiffman et
al. 20143

Exclusion Criteria:

Self-report:

1. Chronic widespread pain

2. Current use of opioids or other pain medications (e.g., ibuprofen/acetaminophen) that
cannot be stopped <3 days prior to testing

3. Conditions/diseases associated with altered pain perception: neurological (e.g.,
multiple sclerosis, trigeminal neuralgia) psychiatric disorders, diabetes, neoplasm
and cardiovascular disorders

4. Injury to hands

5. Substance abuse

6. MRI contraindications including pregnancy