Final Report of the TMJD Working Group

A Systems Approach to Understanding TMJDs

September 16-18, 2007

National Institute of Dental and Craniofacial Research

Temporomandibular Muscle and Joint Disorders Interagency Working Group

Meeting Summary and Report to the National Advisory Dental and Craniofacial Research Council

Contents
 
Topic:                                                                                                              Page:

Executive Summary                                                                                      2

Background                                                                                                     5

            Description of the Disorder                                                               5
            Epidemiology                                                                                       6
            Federal Support of Research                                                            6
            TMJD Interagency Working Group                                                    7
            Recent NIH- and NIDCR-Sponsored Initiatives                             9

Need For A New Approach                                                                            10

Discussion of  Workshop Questions                                                         12

Appendix 1: TMJDs – Research Needs and Opportunities                     15
Appendix 2: Workshop Participants                                                              19
Appendix 3: Meeting Agenda                                                                           20                                                                                                                                                                             
 

Executive Summary

The Workshop participants were pleased to be invited to this unique Workshop as thought leaders to explore a new approach to a set of prevalent disorders that afflicts many patients and frustrates the healthcare community for lack of evidenced-based methods to treat these disorders.  A systems approach to research and design is regularly used in engineering but is relatively new to biology.  The approach is usually one of the studies of a process to determine a desired outcome and the most effective way of obtaining this outcome.  In undertaking this approach one does not have an understanding of all (or perhaps any) of the intermediate steps.  Systems approaches and analyses are powerful methods to compliment the reductionist research that predominates in biology.

The background and charge to the Workshop are presented subsequently.  The presenters are all, except for Drs. Maixner and Clauw, new to the challenges of diagnosing, preventing and treating TMJDs.  They provided a fresh examination of the field and thoughtful experience-based ideas of how to move the field forward.  Based on the Workshop discussion, the participants created a set of guiding principles to guide the formation of specific recommendations for the NIDCR Council to consider.  The overall goal of these principles is to support and translate research that addresses the needs and concerns of TMJD patients -
 
The recommendations should support research that:

1. Uses integrative, interdisciplinary and interactive approaches
2. Uses the best approaches and technologies available
3. Insures that there is excellence in all programmatic aspects
4. Identifies clear measurable goals with accountability for the deliverables with a  
             timetable
5. Enhances our understanding of the etiology and pathophysiology of TMJDs as well      
             as the intermediate phenotypes and their relationship to co-morbid conditions
6. Incorporates a balance between discovery and hypothesis testing within a systems framework (i.e., views TMJD not as an isolated disorder or condition but as part of an entire complex system which has many facets and connections)
7. Is integrated horizontally in order to avoid ‘silo-building’ and to encourage involvement and collaboration among a wide variety of investigators with diverse perspectives, expertise and interests
8. Develops a cadre of investigators on TMJD research by bringing experienced investigators in and training new investigators
9. Builds upon and expands existing information and scientific resources (e.g., data sets available from OPPERA, other scientific studies involving TMJD/related conditions, patient organization databases, primary care providers) in order to advance current research, and encourage new questions/directions/avenues of research
10. Represents a partnership between scientists, patients and funding agencies.

Most of the concluding discussion focused on the first question asked of the participants:

• Is the science sufficiently advanced to support a systems approach to the study of TMJDs? 

There was a spectrum of opinions ranging from cautious optimism to uncertainty about the value of using systems approaches at this time.  The thoughts on this question are outlined in the body of the report (pages 10-14).   The members did not develop unanimous agreement on this question.
 
There was a fruitful discussion on possible research opportunities that could be undertaken if systems approaches were used.   Based on the guiding principles and this discussion, the following research opportunities were considered.  There was general agreement that if systems initiatives were planned, they include active management by the NIH-NIDCR.
 
Possible Research Opportunities
 
1) Support multidisciplinary research on the causes, pathophysiology, prevention, diagnosis and treatment of TMJDs.
 
            a) Discovery and hypothesis driven research by co-principal investigators.
            b) Resource human and animal databases available to applicants.
            c) Annual research planning and investigator meetings.
            d) Data network formatted for availability to everyone
 
 2) Establish data-mining studies of clinical, patient advocacy and basic science databases (e.g., OPPERA, other chronic diseases, and TMJ Association Databases).

            a)  Genetic, environmental, therapeutic and management differences could be analyzed using bioinformatic systems models for specific outcomes, new associations and variances.
             b)  This could produce new hypotheses and new approaches for investigator-initiated research grant applications.

 3) Implement TMJD training programs. 

            a)      Summer program, nationally advertised, for introducing trainees to TMJDs.
            b)      Post-doc fellowships, research residencies, faculty exposure/retraining   
                     (basic and clinical)
            c)      Mentoring and development of new faculty 
 
            
 
Background

Description of the Disorder.  Temporomandibular muscle and joint disorder (TMJD) is a complex heterogeneous condition. It likely represents a collection of disorders with varying etiologies, affecting the tissues of the masticatory muscles and the temporomandibular joint itself (TMJ).  Due to this complexity and our lack of a complete understanding of the underlying mechanisms of disease onset and progression, the treatment for many patients with TMJD currently is less than satisfactory. The etiology and pathophysiology of complex disorders like TMJD may involve the interaction of genetic and environmental influences. In addition, there is likely a psychosocial set of factors that add to the complexity of TMJD, not only when considering diagnosis and treatment, but also in the context of pathological mechanisms associated with the disorder and other diseases that seem to coexist with TMJDs as co-morbidities. Peripheral defects in sensory neuron or muscle function, abnormal neurotransmission, central integration of sensory and motor inputs, and the societal and cognitive influences on these processes, may all interact and influence the pathological process and expression of associated chronic co-morbidities such as irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome, multiple chemical sensitivity, cardiovascular abnormalities, and in some instances depression and anxiety.

The major symptoms of TMJD are chronic myofacial pain (particularly in the muscles of mastication), restricted range of jaw motion, jaw locking, and abnormal popping and clicking noises in the TMJ, although this latter symptom is not by itself either predictive or diagnostic of TMJD. In addition, other symptoms are known to occur in this disorder such as pain in the joint itself and in the area surrounding and radiating from the joint including the ear, neck, shoulder, and back; vertigo; diminished hearing or ringing in the ear; chronic headache; blurred or double vision; sleep disturbances; and difficulty in swallowing. Besides these symptoms, depression, anxiety disorders, and substance abuse may also be associated with TMJDs.
 
Epidemiology.  It has been estimated that TMJDs affect approximately 10 million individuals, the majority of them women during their childbearing age. More recent epidemiological data, collected as part of the NIH-sponsored Osteoarthritis Initiative which includes both men and women, show that approximately 7% of 4796 individuals responding to questions about osteoarthritis pain, experienced pain in the jaw joint or in front of the ear during the 30 days prior to the survey. An additional 3.3% experienced facial or cheek pain or aching during the same 30 day period.  Approximately 5.3% of those sampled expressed concern about the jaw/ear pain while only about 2.5% were concerned about the facial/cheek pain.  When approximately 350 individuals were questioned about how long the joint/ear pain lasted or about any limitations caused by the pain, it was reported that the pain lasted for an average of approximately 9.0 days and that an average of approximately 1 day was lost to usual activities (e.g., work, school, etc) during the 30 days prior to the survey.  Similar information collected from 157 individuals with pain in the face/cheek showed that it lasted an average of 9.8 days and kept individuals from usual activities for an average of 1.3 days.  Responses to questions about the occurrence of pain during a period 6 or more months prior to the survey showed that approximately 6.8% had pain in the jaw joint or in front of the ear while approximately 3.1% had pain in the face or cheek 6 or more months prior to being queried.  


Federal Support of Research.  Research involving TMJDs has, for the most part, been from the National Institute of Dental and Craniofacial Research (NIDCR).  A history of support between FY1996 and 2005, summarized in Table 1, shows that support has ranged between 3.4% and 5.1% of the total NIDCR research budget.


Table 1.  NIDCR support of TMJD research (in $000).

Over the same period, as illustrated in Table 2, other ICs have increased their support for TMJD research from 2.8% to 24.5% of total NIH funding for TMJD research.


Table 2.  NIH support of TMJD research by individual ICs (in $000).