Translational research of temporomandibular joint pathology: a preliminary biomarker and fMRI study

Abstract

Background: The temporomandibular joint (TMJ) is well innervated by braches of the trigeminal nerve. The temporomandibular joint disorders (TMD) can cause neural-inflammation in the peripheral nervous system (PNS) at the site of injury, or compression, and may have systemic effects on the central nervous system (CNS). Neural-inflammation causes elevations in cytokine expression and microglia activation. When the site of injury, or compression is treated, or relieved, neural inflammation is reduced. These changes can be seen and measured with fMRI brain activities.Methods: For this study, patients with comorbid TMD and systemic/neurologic conditions were compared using clinical diagnostic markers, inflammatory, pain, tissue destruction enzymatic biomarkers, and functional magnetic resonance imaging (fMRI) activity of the brain, with and without a custom-made dental orthotic. Results:Our results showed a correlation between the clinical diagnosis of the pathological TMJ, biomarkers and the fMRI study. There was a marked elevation of biomarkers in samples taken from TMJ of patients who were clinically diagnosed with TMD. The fMRI study of TMD patients showed an abnormal hyper-connected salience network and a diminished blood flow to the anterior frontal lobes when they did not wear their customized dental orthotics. Conclusions:Our findings highlight the importance of TMJ-CNS connections and use of fMRI as an investigative tool for understanding TMD and its related neurological pathologies.

Preclinical models of deep craniofacial nociception and temporomandibular disorder pain

“…Biochemical studies demonstrate the changes in the level of inflammatory mediators, which can sensitize the nociceptors in the deep craniofacial tissues [ [22] , [23] , [24] , [25] ]. Proinflammatory mediators affect nociception in the deep craniofacial tissues.…”

“…TMJ or masseter muscle injection of opioids decreases hyperalgesia evoked by mechanical stimulation to the face in painful TMD [ 48 , 49 ], whereas intra-TMJ capsule injection of lidocaine shows less reduction of the jaw opening pain with disc displacement without reduction [ 50 ]. Neuroimaging technology enables visualization of structural changes in the nervous system associated with nociception [ 23 , 51 ]. Further, the magnetic resonance imaging (MRI) demonstrates that painful TMD patients show neural degeneration of the trigeminal nerves [ 20 , 52 ].…”

Cortical representation of experimental periodontal pain: a functional magnetic resonance imaging study

“…Activation of pain systems even during discrete pain percepts (VAS = 2) is evidence that painful sensations are indeed elicited and should be taken as biological signatures of potentially harmful events. In the same line, customized dental orthotics induced a reduction of pain and associated signs of neural inflammation in temporomandibular joint disorder patients and mechanical treatment reduced abnormal hyper-connected salience networks 40 , which are primarily composed of the anterior insula and dorsal anterior cingulate cortex 41 .…”

Evolution patterns of SARS-CoV-2: Snapshot on its genome variants

“…Environmental factors, e.g., temperature, population density and air pollution, seem to affect viral spreading and mortality rate [ [20] , [21] , [22] , [23] , [24] ]. In addition, interventions aimed at limiting people movement and interactions have been implemented in several areas of the globe to curb the pandemic.…”