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Meeting Summary and List of Recommendations: Roundtable on The Temporomandibular Joint in Health and Disease

Temporomandibular joint disorder (TMJD) comprises a group of conditions that leads to jaw dysfunction and causes pain in the jaw joint and the muscles that control jaw movement. Recent epidemiological data suggest that between 5-10% of the US adult population experience TMJD pain. It is more common in women than men. Some people develop a long-term, chronic temporomandibular joint condition that can be debilitating and difficult to treat. Effective therapies for TMJD are less than satisfactory due to our incomplete understanding of the etiology and pathological mechanisms involved in disease. Some recent results suggest that chronic TMJD is not a localized orofacial condition, but rather, a more complex disorder involving central nervous system (CNS) dysfunction. Subjects with chronic TMJD usually present with other chronic pain conditions affecting other areas of the body, consistent with CNS dysfunction.

The temporomandibular joint, or jaw joint, is a modified hinge-type joint consisting of the mandible and the temporal bones. The articular disc, composed of fibrocartilage, separates the condyle of the mandible from the mandibular fossa of the temporal bone. The temporomandibular joint is one of only a few synovial joints in the body to have an articular disc. Three main ligaments connect the mandible to the temporal bone and help to stabilize the joint, serve as a hinge, and prevent excessive movements of the mandible. Major muscles acting on the joint include the masseter, temporalis, and lateral and medial pterygoid. Sensory innervation of the joint originates from the mandibular branch of the trigeminal nerve. Surrounding tissues are innervated by proprioceptive and mechanosensitive nerve endings, which are important in initiating movement and controlling the mechanics of the joint. Blood supply to the joint and surrounding muscles is provided from the external carotid and maxillary artery and its branches. Interestingly, the articular disc of the temporomandibular joint is not innervated and the central portion of the disc does not contain a blood supply. Disc dysfunction is thought to be an early sign leading to temporomandibular joint pain.

Recent research efforts on TMJD have focused on mechanisms underlying the development and persistence of orofacial pain, pain modulatory pathways in the trigeminal system, and novel therapeutic approaches. Research on tissue regeneration and repair of damaged or dysfunctional temporomandibular joints is focused on engineering the disc complex and developing multi-tissue interfaces such as a bone-cartilage interface. In order to develop better approaches for repair of dysfunctional joints, regeneration of new joint structures, therapeutic interventions, and prevention chronic disease, a more detailed understanding of tissue mechanics, joint tissue interfaces, neurological control, and inflammatory joint processes, scaffold designs and materials, and use of stem cells need to be determined. In short, the biology of the temporomandibular joint in health and disease must be delineated in order to develop new, efficacious treatments for temporomandibular joint disorders.

A roundtable discussion was held on May 3, 2013 to explore the structure and function of the temporomandibular joint as it relates to healthy behavior and to pathology. Discussion topics included factors important in the onset and maintenance of chronic TMJD, specific molecular biomarkers of disease, new methods of measuring joint function, and future research directions.

The purpose of this roundtable meeting was to bring together scientists with expertise in areas related to the structures/tissues of the temporomandibular joint and apply their knowledge to explore new research approaches to advance our understanding of temporomandibular joint function. The goal of this meeting was to provide a set of research recommendations to the scientific community that will create/develop a path forward in contemporary, multidisciplinary research on temporomandibular joint function in health and disease. The intent of this roundtable meeting was to identify gaps in research on the biology of temporomandibular joint tissues, to identify unanswered questions relating to interactions of joint tissues, and to identify novel scientific methodologies, which taken together, would lead to a forward thinking approach to future research on the temporomandibular joint.

Twelve panelists participated in this roundtable discussion. Several Institute Directors or their representatives, Program Staff from NIDCR, NIAMS, and NIBIB, and patient advocates also attended. The meeting was divided into 5 sessions on bone structure, function, and bioengineering; muscle structure and function; collagenous tissues (articular disc, ligaments, and tendons) and bioengineering; vascularization of the joint; and measurement(s) of joint health and disease. Panelists developed a consensus list of research recommendations in the final afternoon session.

Research Recommendations

The panel members generated a comprehensive list of research topics that require additional effort to fill important gaps in our knowledge of the functioning of the temporomandibular joint. These gap areas aligned in the major structural components of the joint including the bones, muscle, collagenous tissues, and the vascular system. In addition, development of new technologies and methods that can monitor the joint in health, disease and in treatment outcomes was considered an important area.

There were several main themes that recurred during each of the individual discussion sections that were considered important: 

  • Sex hormone influence on and sex/gender differences in structure, function, and plastic responses of temporomandibular joint tissues
  • Tissue interactions among components of the joint were deemed critical especially in the context of developing methodologies for joint repair and regeneration (bone-muscle, disc-ligament, both sensory and motor nervous system interactions with other joint tissues, and vascular interactions with other joint tissues)
  • Development of new animal models for temporomandibular joint research and treatment options and new animal models of temporomandibular joint pain, given the panel felt that these were needed especially for studies on joint replacement/engineering efforts and therapeutics development (in this regard, emphasis was placed on considerations about small vs. large animals and usefulness/relevance of large animals similar to humans in temporomandibular joint size and spatial configurations)
  • Innervation of all temporomandibular joint tissues, especially bone and muscle, but also of the vascular system
  • Identification at the molecular level of proteins, genes and transcriptionally regulated pathways in temporomandibular joint tissues during development and under normal and pathological conditions
  • Determine relationships of temporomandibular joint motion, mechanical forces, physical properties of joint tissues, and cellular mechanotransduction to better understand joint development and disease progression as well as to develop treatment options

Specific research directions


  • Understanding of molecular pathways of a) joint development, growth plate vs. long bone, b) (+/-) feedback loops in mechanical loading in both health and disease, c) subchondral bone function, and d) osteoarthritis
  • Better understanding of physiological and pathological loading related to integration of mechanical cues, bone remodeling, and bone loss
  • Engineering of replacement bone, engineering models and animal models


  • Understanding molecular pathways in muscle tissue during development and in mature muscle, delineating molecular differences in muscles of mastication vs. appendicular skeletal muscle, molecular pathways of energy metabolism
  • Muscle regeneration: role of satellite cells, balance of proliferation vs. apoptosis, differences in craniofacial (masseter) vs. appendicular (limb) skeletal muscle, studies of reloading after disuse
  • Role of fatty fibrotic infiltration of muscle

Collagenous tissues

  • TMJ disc: its molecular profile, biomarkers of cell lineage, species comparisons of physical properties of the disc, transcriptional profiles during normal and pathological loadings
  • Mechanisms of TMJ disc/ligament/tendon/cartilage repair, identify synthetic and degradative pathways
  • TMJ cartilage, studies of chondrocytes: proliferation, apoptosis, necrosis, and autophagy
  • Studies focused on similarities and differences between the condyle and other growth plates to gain insight into possible mechanisms of regeneration.
  • Role of mechanical loading in TMJ soft tissue development, growth, remodeling, and degeneration.

Vascularization of the temporomandibular joint 

  • Studies on vascularization versus angiogenesis of joint tissues, define factors important in onset and termination of vascularization, the role of hypoxia on individual cell types
  • Angiogenesis studies: its modulation by pain, its modulation/inhibition by collagen, the impact of chronic versus acute injury, mechanism of promotion of muscle healing by angiogenesis
  • Role of immune cells and their trafficking in pro- and anti-angiogenic effects
  • Positive feedback loop/cycle of angiogenesis and inflammation: what are the major molecular players and pathways, what are the mechanisms that can break the cycle to promote healing, what treatment options are available for completely or partially blocking, and enhancing angiogenesis

Measurements of joint health and disease, diagnostics, and therapeutic outcomes

  • Imaging: important to go beyond static imaging of the joint and examine dynamic imaging of joint function; use of 3-D imaging of joint structure and joint quality, leverage imaging technologies and data sets from other disciplines (i.e. cohorts with imaging of brains with neurological disease)
  • Biomarkers: use of biomarkers to address changes in structure/function in longitudinal studies (during treatment and in development), use of biomarkers with imaging to increase specificity of measures, employ symptomatic and asymptomatic subjects in their identification
  • Heterogeneity: understanding of the range of “normal” variation in joint morphology vis-à-vis clinical signs and symptoms of disease
  • Treatment considerations: efficacy/specificity of local delivery, use of mesenchymal stem cells, and use of appropriate animal models for initial treatment experiments (size and spatial approximations of human temporomandibular joint)

Next steps

The discussions at the Roundtable and this set of research recommendations will be considered by Program Staff in our continuing portfolio assessment and growth. The Institute will use this information in developing future research initiatives and in preparing our next Strategic Plan. NIDCR will seek input and partnerships with NIAMS and NIBIB in the implementation of any funding opportunities that may emerge from these activities.

The Temporomandibular Joint in Health and Disease
May 3, 2013
Democracy I, Room 602
6701 Democracy Blvd., Bethesda, MD 20817


8:15 am  Welcome and Introductions
John W. Kusiak, PhD, Program Director, National Institute of Dental and Craniofacial Research, NIDCR

Opening remarks:
Dr. Martha J. Somerman, DDS, PhD, Director, National Institute of Dental and Craniofacial Research, NIDCR
Dr. Robert H. Carter, MD, Deputy Director, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIAMS
Dr. Roderic I. Pettigrew, PhD, MD, Director, National Institute of Biomedical Imaging and Bioengineering, NIBIB

8:30 am Overview of the temporomandibular joint: Clinical and biological perspectives
Dr. Raphael and Dr. Yao

8:50 am Bone structure, function, and bioengineering
Lead Discussant: Dr. Alliston

9:30 am Muscle structure and function
Lead Discussant: Dr. Barton

10:10 am Break

10:30 am Collagenous tissues (articular disc, ligaments, and tendons) and bioengineering
Lead Discussant: Dr. Yao

11:10 am Vascularization of the joint
Lead Discussant: Dr. Chen

11:45 am Lunch

12:45 pm Measurement(s) of joint health and disease, novel methods to measure joint mechanics, joint motion, pathological markers, and end points of therapeutic interventions

Lead Discussant: Dr. Ratcliffe

1:30 pm Brief remarks
Dr. Larry Tabak, Deputy Director, NIH

1:40 pm Future research directions – Development of a set of research recommendations
The Group

3:00 pm Summary and Concluding remarks
Dr. Somerman and Dr. Kusiak

3:15 pm Adjournment


Discussion Topics 

  • What are the scientific and knowledge gaps in the research literature on human joint biology and function? On temporomandibular joint structure and function?
  • What insights from your own research fields can be brought to the area of temporomandibular joint structure and function?
  • What are some of your current research findings that may impact research on temporomandibular joint research?
  • What new technologies and can be applied to research on the temporomandibular joint?
  • What are some innovative research approaches that are likely to have a major impact on temporomandibular joint research?
  • What are some of the current impediments (funding aside) to advancing our understanding of joint structure and function?

The Temporomandibular Joint in Health and Disease
May 3, 2013
Democracy I, Room 602
6701 Democracy Blvd., Bethesda, MD 20817


Tamara N. Alliston
Department of Orthopaedic Surgery
University of California, San Francisco
513 Parnassus, S-1155, Box 0514
San Francisco, CA 94143

Elisabeth R. Barton
Department of Anatomy & Cell Biology
Dental Medicine
University of Pennsylvania
240 S 40th St 441 Levy Oral Health Sci. Bldg.
Philadelphia, PA 19104

Robert H. Carter
Deputy Director, NIAMS
National Institutes of Health
31 Center Drive
Bethesda, MD 20892

Lucia H. Cevidanes
School of Dentistry
University of Michigan
1011 North University St.
Ann Arbor, MI 48019

Christopher Chen
Department of Bioengineering
University of Pennsylvania
3320 Smith Walk
Philadelphia, PA 19104

Christine B. Chung
Radiology Department
University of California, San Diego
9500 Gilman Dr. # 9114
La Jolla, CA 92093

Renny T. Franceschi
Periodontics and Oral Medicine
School of Dentistry
University of Michigan
1011 N. University Avenue
Ann Arbor, MI 48109

John Kusiak
Program Director
Molecular and Cellular Neuroscience Program
National Institutes of Health
6701 Democracy Blvd.
Bethesda, MD 20892

Nancy E. Lane
Department of Internal Medicine
University of California Davis
4625 2nd Avenue, Suite 1002
Sacramento, CA 95817

Sharmila Majumdar
Radiology and Biomedical Imaging
School of Medicine
University of California, San Francisco
1700 4th St., Suite 203
Box 2520
San Francisco, CA 94158

Karen G. Raphael
College of Dentistry
New York University
380 Second Avenue, 3rd Floor, Suite 301
New York, NY 10010

Anthony Ratcliffe
Synthasome, Inc.
3030 Bunker Hill Street, Suite 308
San Diego, CA 92109

Ravinder Reddy
Department of Radiology
University of Pennsylvania
422 Curie Blvd., B1 Stellar-Chance Laboratories
Philadelphia, PA 19104

Roderic I. Pettigrew
Director, NIBIB
National Institutes of Health
31 Center Drive
Bethesda, MD 20892

Martha Somerman
Director, NIDCR
National Institutes of Health
Building 50, Room 4120
50 South Drive
Bethesda, MD 20814

Hai Yao
Department of Bioengineering
Clemson University
Department of Craniofacial Biology
Medical University of South Carolina
68 President Street, Room BE202
Charleston, SC 29425

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This page last updated: February 26, 2014