Read the Latest News

National Academy of Medicine Study on Temporomandibular Disorders

The first meeting of the National Academy of Medicine Committee on Temporomandibular Disorders (TMD): From Research Discoveries to Clinical Treatment will be held Tuesday, January 29, 2019 at the National Academy of Sciences building in Washington, D.C.&

Attention Canadian TMJ Implant Patients

The Trial of the Class Action brought by Canadian patients who were implanted with Vitek Proplast TMJ implants, against Health Canada, alleging negligent regulation starts on April 1, 2019 in Toronto.

Long-term Changes in Biopsychosocial Characteristics Related to Temporomandibular Disorder: Findings from the OPPERA Study

The following article by Roger B. Fillingim, Gary D. Slade, Joel D. Greenspan, Ronald Dubner, William Maixner, Eric Bair, and Richard Ohrbach was published in the journal of Pain, November 2018. We are grateful to Dr. Fillingim for writing the following

National Academy of Medicine to Conduct a Study on Temporomandibular Disorders

We want you to be among the first to know that because of the advocacy efforts of The TMJ Association, the National Academy of Medicine (NAM) will conduct a first-ever study on Temporomandibular Disorders (TMD).

Dentists in Distress

Fear of the dentist is practically a rite of passage in youth. Growing up, I wasn't exactly afraid of the dentist; rather, any excuse to leave school early was a powerful incentive. These days, I have a more complicated relationship with dentistry: I go to get answers and try to feel better, but I always pop a prophylactic ibuprofen or two in case my jaw protests from the oral gymnastics.

Sustained and Repeated Mouth Opening Leads to Development of Painful Temporomandibular Disorders Involving Macrophage/Microglia Activation in Mice

  • May 30, 2018

The following was published in the March 2018 issue of Pain. This research was conducted by Guan Yun Frances Wang; Xiang Qun Shi; Wenjia Wu; Maria Gueorguieva; Mu Yang; Ji Zhang, Faculty of Dentistry, McGill University, Montreal, QC, Canada.  

Abstract: Temporomandibular disorder (TMD) is a set of heterogeneous musculoskeletal conditions involving the temporomandibular joint (TMJ) and/or the masticatory muscles. Up to 33% of the population has had at least one symptom of TMD with 5-10% of them requiring treatment. Common symptoms include limited jaw movement, joint sound, and pain in the orofacial area. Once TMD becomes chronic, it can be debilitating with comorbidities that greatly reduce one's overall quality of life. However, the underlying mechanism of TMD is unclear due to the multicausative nature of the disease.  

Here, we report a novel mouse model of TMD where a bite block was placed in between the upper and lower incisors such that the mouth was kept maximally open for 1.5h per day for 5 days. Following sustained mouth opening, mice developed persistent orofacial mechanical allodynia and TMJ dysfunction. At the cellular level, we found masseter muscle dystrophy, and increased proteoglycan deposition and hypertrophic chondrocytes in the mandibular condyle. Increased F4/80 macrophages were also observed in the masseter muscles and the TMJ posterior synovium. We also found ATF3 neuronal injury and increased F4/80 macrophages in the trigeminal ganglia. Microglia activation was observed in the trigeminal subnucleus caudalis. Inhibiting macrophage/microglia activation with a colony stimulating factor-1 receptor inhibitor prevented the development of orofacial mechanical allodynia, but not TMJ dysfunction.

This study suggests that mouth opening for an extended period of time during dental treatments or oral intubations may risk the development of chronic TMD and inflammation associated with macrophage/microglia in the tissue and trigeminal system contributes to the development of TMD pain. 

TMJ Disorders

Comments:

Login or Register to add Comment