Journal of Dental Research http://jdr.sagepub.com/Temporomandibular Disorders: Moving from a Dentally Based to a Medically Based Model Charles S. Greene and Daniel M. Laskin J DENT RES 2000 79: 1736 DOI: 10.1177/00220345000790100101 The online version of this article can be found at: http://jdr.sagepub.com/content/79/10/1736 Published by: http://www.sagepublications.com On behalf of: International and American Associations for Dental Research Additional services and information for Journal of Dental Research can be found at: Email Alerts: http://jdr.sagepub.com/cgi/alerts Subscriptions: http://jdr.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav Citations: http://jdr.sagepub.com/content/79/10/1736.refs.html Downloaded from jdr.sagepub.com by guest on March 29, 2011 For personal use only. No other uses without permission.
E1- 1Charles S. Greene and Daniel M. Laskin* Temrporomand ibu arDepartment of Oral & Maxillofacial Surgery, University of Illinois,College of Dentistry, Chicago, IL 60612; and *Department of Oral & Disorders: MovingMaxillofacial Surgery, Virginia Commonwealth University, School ofDentistry, Richmond, VA 23298-0566; *corresponding author,Dlaskin Cden .den.vcu.edu from a Dentally BasedJ Dent Res 79(10): 1736-1739, 2000 to a Medically Based ModelINTRODUCTION etiology, and treatment. Originally, Laskin had no particular bias for or against any of the popular etiologic theories of theThe year 2000 marks the end of a century in which many time, but he was impressed by the findings of Laszlo I traditional dental concepts were subjected for the first time Schwartz and his colleagues at Columbia Universityto some type of systematic inquiry. This kind of investigation (Schwartz, 1959). Their research had indicated that most so-produces results that differ considerably from the results of called "TMJ pain and dysfunction" was probably myofascial"Discovery" experiments (such as those often described in this in origin, and their etiologic perspective emphasizedsection of JDR), in which new diseases or new diagnostic psychological stress rather than occlusal disharmony as themodalities are brought to light. This essay describes the primary cause of the problem.background of nearly 40 years of systematic inquiry into the By 1965, the University of Illinois Temporomandibularsubject of temporomandibular disorders (TMD), much of Joint and Facial Pain Research Center was established, andwhich was directed at questioning the validity of the traditional Charles Greene joined the group as clinical director. From theconcepts in this field, and how this eventually changed the beginning, one or more psychologists were always included onclinical management of patients. It also recounts the struggle to the team. Most of the oral and maxillofacial surgery residentspersuade the dental profession to move from the past into the also contributed to many of the studies as part of a Master ofmodem arena of TMD diagnosis and treatment. Science degree program. The collaboration between Laskin and Greene began a working relationship that has continued toSINGLE-MODALITY TREATMENT EXPERIMENTS this day.In 1963, the University of Illinois College of Dentistry submitted In the early 1960s, conventional wisdom held that allan application to the National Institute of Dental Research for a "TMJ" patients had more or less the same kind of problem,five-year program-project grant to study the various aspects of usually referred to as "TMJ syndrome". This oversimpli-temporomandibular joint (TMJ) growth and development, fication generally was accompanied by the concept that thisanatomy, physiology, and pathology, as well as the various clinical condition was caused by some type of occlusal/skeletaldisorders. The co-principal investigators were Seymour Yale, who disharmony and, therefore, proper treatment inevitably wouldhad recently become Chairman of the Department of Oral require the correction of these morphofunctional faults. ThisRadiology, and Daniel Laskin, who was an associate professor in mechanistic viewpoint had previously been challenged bythe Department of Oral and Maxillofacial Surgery with an interest Laszlo Schwartz and his co-workers (most notably by thein the role of the mandibular condyle in facial growth. Included as psychiatrist, Ruth Moulton), who believed that myofascialco-investigators were Milton Engel, Allan Brodie, and E. Lloyd pain and psychological stress were important etiologic factors.DuBrul. This grant was subsequently funded for $872,000, the However, they had not made many converts by 1966, whichlargest grant that the dental college had received up to that time. was when our work began.Shortly thereafter, Yale became the dean of the college, and the We decided to conduct a series of single-modalityresponsibility for being the principal investigator and implementing treatment experiments, using placebo controls in each one,and administering the grant fell to Laskin, who continued to direct to see which of the existing therapeutic procedures mightthe program and to secure NIDR funding for 23 consecutive years. have "real" effectiveness. In these studies, we looked at Although Laskins original interest in the several medications (Greene and Laskin, 1969, 1972; Ryantemporomandibular joint was related to craniofacial growth, et al., 1985), various physical therapies (Lerman, 1968;of necessity this interest soon broadened into the clinical Sutcher et al., 1969; Eisen et al., 1984), oral bite appliancesfield of temporomandibular disorders (referred to as TMJ (Greene and Laskin, 1971; Block and Laskin, 1978), TENSsyndrome at that time). He set about establishing a team that (Block and Laskin, 1980; Gold et al., 1983), and evenwould subsequently explore both the basic and clinical psychological therapies (Pomp, 1974; Shipman et al., 1974;aspects of these problems, with emphasis on diagnosis, Dohrman and Laskin, 1978), and found some remarkable results. Every experiment produced a fairly high (35-60%) placebo response, with even higher responses produced byKEY WORDS: temporomandibular disorders, maxillofacial the "real" treatments.pain, placebo therapies. Nobody had previously conducted any controlled clinical experiments such as these in this field, despite the fact that aReceived March 28, 2000; Accepted July 10, 2000 "TMJ syndrome" was being diagnosed and treated since the1736 Downloaded from jdr.sagepub.com by guest on March 29, 2011 For personal use only. No other uses without permission.
JDentRes 79(10) 2000 DISCOVERY! 17371930s. Our original intent in using placebos in the medication anxiety, depression, coping skills, and similar psychologicalstudies was entirely traditional, but the high percentage of parameters that were being studied in other kinds of painpositive outcomes prompted us to develop and use some rather patients (Shipman et al., 1974; Olson and Schwartz, 1977;innovative placebos in succeeding studies. For example, we Schwartz et al., 1979; Millstein-Prentky et al., 1979; Malow etdecided to try a "realistic prescription" procedure for al., 1980; Malow, 1981; Greene et al., 1982). They alsodispensing a placebo medication rather than using the typical applied various experimental psychophysiologic techniques todouble-blind technique with secret coded numbers on the bottle assess pain tolerance, response specificity, evoked brain(Laskin and Greene, 1972). We had our University pharmacy potentials, and other parameters of altered mind-bodyprepare capsules of lactose that could be obtained only by the relationships (Lupton and Johnson, 1968; Mercuri et al., 1979;presentation of a written prescription and the paying of a small Malow et al., 1980; Diaz-Clark et al., 1982; Rosenfeld et al.,fee; the "drug" was given the suggestive name Myolax, and it 1983; Olson and Malow, 1986). The results of these studiesproved to be about 50% more effective than the same placebo contributed to the formulation of Laskins psychophysiologicgiven in a double-blind protocol. theory of myofascial pain etiology (Laskin, 1969). This theory, We also designed the first "placebo splint", which was along with the work of Schwartz and Moulton, became thesimply an acrylic palatal appliance that did not alter the foundation for much of todays discussions aboutpatients occlusion (Greene and Laskin, 1971). This device biopsychosocial concepts, which in turn led to thewas not only quite successful in relieving symptoms, but it development of the Axis I-Axis II dichotomy in the Researchalso produced responses from many patients about how their Diagnostic Criteria (RDC/TMD).jaw and bite felt different while wearing it. Our sham TENS As a result of our initial clinical, psychological, andprocedure used a machine with lights blinking, but with no psychophysical studies, and the subsequent works of others,electrical current being transmitted through the electrodes TM disorders have been moved away from their traditional(Gold et al., 1983). niche in the world of dentistry into a more appropriate position. Finally, we were ready for "the big one"-we pretended to Instead of being considered as mechanical morphofunctionaladjust the bite (equilibrate) in a series of 25 TMD patients after problems, it is now clear that they are orthopedic,doing a thorough occlusal analysis and discussing it with the musculoskeletal conditions usually featuring pain as thepatient. Little did we expect that we were about to set our all- dominant symptom, with significant psychological associationstime high placebo response record: 64% of these patients that affect their etiology and management. Yet, treatment of reported a major or total improvement after only two sessions these disorders remains within the dental profession as one of of mock equilibration (Goodman et al., 1976), and most of our primary responsibilities, so that it becomes necessary for them were quite happy with the "improvement" in how they dentists to learn how to care for TMD patients within this new were biting. paradigm. To do so, they must use their training in oral The results of these studies demonstrated that many TMD medicine rather than the more traditional morphofunctional patients are strong placebo responders and that such effects, treatment approaches. plus the procedural aspects of the doctor-patient relationship, have a strong influence on the outcome of various rational CURRENT STATUS OF THE TMD FIELD therapeutic approaches. They also explained why certain other After 35 years of research that has been conducted around treatments can sometimes be effective, even though they lack a the world, a scientific foundation for the TMD field has been scientific basis. In essence, they showed that with TMD established. Converging information from several diverse patients it is often not what is done for them, but how it is done, disciplines has contributed to this foundation, so that today that is important. we speak of TM disorders in terms of orthopedic principles, neurophysiology of pain, molecular pathophysiology ofPROFESSIONAL CHALLENGES joints and muscles, and behavioral aspects of chronic pain.Naturally, the first challenges to our results came from various We diagnose and classify TMD patients within amembers and groups within the "occlusion-changing" biopsychosocial framework, and we treat many of themcommunity of dentists. They insisted that we were merely successfully with empirically validated, conservativeproducing short-term successes, which would quickly fade therapies.once we stopped "manipulating" these patients, because we Unfortunately, these conclusions are not yet universallywere not correcting the underlying dental causes of their endorsed or even accepted by all members of the dentalproblems. In both 1974 (Greene and Laskin) and 1983 (Greene profession. In this regard, dentistry remains a somewhatand Laskin), we published our long-term follow-up data on the fragmented profession, with each discipline having its ownuse of conservative and reversible treatments (including viewpoint about many TMD issues. Because these disordersplacebos). Analysis of these data showed not only that most of clearly do not belong to any single dental specialty, they endour positive treatment effects were enduring, but also that up being treated by almost everybody. As a result, thepositive placebo responders did just as well over the years as special interests and training of each group become imposedthe real treatment patients. on the patients. The old joke says that the fate of a TMD During the same period when we were conducting these patient is determined by the floor at which the elevator stopsTMD treatment studies, our research team also was studying in a professional office building-not a good state of affairs.psychologic and psychophysiologic issues in these patients. A These traditional differences among dental subgroups have series of outstanding behavioral researchers who worked in become accentuated in recent years through the emergence our Center looked at personality characteristics, stress, of competing TMD academies and societies, and many TMD Downloaded from jdr.sagepub.com by guest on March 29, 2011 For personal use only. No other uses without permission.
1738 Greene & Laskin J Dent Res 79(10) 2000patients today remain at risk of being treated with incredibly patients (abstract). IADR Progr & Abstr: 198.complex and invasive therapies, instead of getting the kind Dohrnann RJ, Laskin DM (1978). An evaluation of electromyographicof conservative (and effective) care that is currently biofeedback in the treatment of myofascial pain-dysfunctionsupported by the body of scientific evidence. syndrome. JAm Dent Assoc 96:656-662. Nevertheless, there currently is much about which to be Eisen RG, Kaufman A, Greene CS (1984). Evaluation of physicalpositive in the TMD field, and the core of fundamental therapy for MPD syndrome patients (abstract). JDent Res 63(Specknowledge continues to grow through research. The Iss):344.NIH/NIDCR and similar government agencies throughout the Gold N, Greene CS, Laskin DM (1983). TENS therapy for treatmentworld have been generously funding both basic and clinical of MPD (abstract). IADR Progr & Abstr:244.research in this field for many years. Most dental schools Goodman P, Greene CS, Laskin DM (1976). Response of patients witharound the world have established special TMD/Orofacial myofascial pain-dysfunction syndrome to mock equilibration. JPain clinics to provide state-of-the-art care for these complex Am Dent Assoc 92:755-758.pain patients. The dental schools also are providing new Greene CS, Laskin DM (1969). Meprobamate therapy for thegenerations of undergraduate and advanced education myofascial pain-dysfunction (MPD) syndrome: a double-blindstudents with the latest contemporary information about this evaluation. JAm Dent Assoc 82:587-590.subject. Advanced training programs lasting up to 2-3 years Greene CS, Laskin DM (1971). Splint therapy for the myofascial pain-also have been developed in many universities in various dysfunction (MPD) syndrome. A comparative study. JAm Dentcountries to produce "specialists" in the orofacial pain field; Assoc 84:624-628.the graduates from these programs have become both the Greene CS, Laskin DM (1972). Therapeutic effects of diazepamcommunity experts for treating complex patients and the (valium) and sodium salicylate in myofascial pain-dysfunctionorofacial pain teachers for the next generation. (MPD) patients (abstract). IADR Progr & Abstr:96. In the end, we can see that the field of TM disorders has Greene CS, Laskin DM (1974). Long-term evaluation of conservativeundergone significant growth and change during the past 35 treatment for myofascial pain-dysfunction syndrome. J Am Dentyears, and we are proud to have been a part of that evolution. Assoc 89:1365-1368.We hope that our early commitment to seeking scientific Greene CS, Laskin DM (1983). Long-term evaluation of treatment foranswers to clinical questions, based on applying basic myofascial pain-dysfunction syndrome: a comparative analysis. Jbiological principles as well as on following the rules for AmDentAssoc 107:235--238proper research, has set an example for many of our Greene CS, Olson RE, Laskin DM (1982). Psychological factors in thecolleagues and our students to follow. Today, the field of TM etiology, progression and treatment of MPD syndrome. JAm Dentdisorders is rich with information derived from the research Assoc 105:443-448.done by us and by so many of our colleagues, and this Laskin DM (1969). Etiology of the pain-dysfunction syndrome. JAminformation has been combined with insights from allied Dent Assoc 79:147-153.disciplines to produce the current mixture of facts and Laskin DM, Greene CS (1972). Influence of the doctor-patienthypotheses in this field. Yet, so many important questions relationship on placebo therapy for patients with myofascial pain-still remain unanswered: Why does the pain become chronic dysfunction (MPD) syndrome. JAm Dent Assoc 85:892-894.in one person and not in another? Why do joints and muscles Lerman MD (1968). A preliminary study of muscle exercises inadapt and remodel successfully in some patients and not in treatment of TMJ pain-dysfunction syndrome (abstract). IADRothers? What are the biologic markers, symptom patterns, Progr & Abstr:190.and behavioral characteristics that will enable us to predict Lupton DE, Johnson DL (1968). The relationship of pain toleranceresponses to therapy? And last but not least, what to personality characteristics among chroniccombination of etiologic factors and host resistance factors temporomandibular joint dysfunction patients (abstract). IADRdetermines who gets TMD and who does not? Progr & Abstr:153. We look forward to the inevitable prospect of seeing these Malow RM (1981). The effects of induced anxiety on pain perception:and many more questions answered in the not-too-distant a signal detection analysis. Pain 11:397-405.future. But regardless of how long it takes, one thing is very Malow RM, Grimm L, Olson RE (1980). Differences in painclear: The framework for understanding TM disorders will perception between myofascial pain-dysfunction patients andcontinue to be developed within a biopsychosocial medical normal subjects: a signal detection analysis. J Psychosom Resmodel-not within the traditional mechanistic dental model that 24:303-309.originated many years ago. Mercuri LG, Olson RE, Laskin DM (1979). The specificity of response to experimental stress in patients with myofascial pain dysfunction syndrome. JDent Res 58:1866-187 1.REFERENCES Millstein-Prentky S, Olson RE (1979). Predictability of treatmentBlock SL, Laskin DM (1978). The use of a resilient latex rubber bite outcome in patients with myofascial pain-dysfunction (MPD) appliance in the treatment of MPD syndrome (abstract). IADR syndrome. JDentRes 58:1341-1346. Progr & Abstr. 92. Olson RE, Malow RM (1986). The effects of relaxation training onBlock SL, Laskin DM (1980). The effectiveness of transcutaneous myofascial pain-dysfunction syndrome. Clin J Pain 1:127-220. nerve stimulation (TNS) in the treatment of unilateral MPD Olson RE, Schwartz RA (1977). Depression in patients with myofascial syndrome (abstract). AADR Progr & Abstr. 519. pain-dysfunction syndrome (abstract). IADR Progr & Abstr: 168.Diaz-Clark A, Rosenfeld JP, Olson RE (1982). Averaged evoked Pomp AM (1974). Psychotherapy for the myofascial pain-dysfunction potentials following painful stimulation in MPD syndrome syndrome: a study of factors coinciding with symptom remission. Downloaded from jdr.sagepub.com by guest on March 29, 2011 For personal use only. No other uses without permission.
J Dent Res 79(10) 2000 DISCOVERY! 1739 JAm Dent Assoc 89:629-634. Schwartz RA, Greene CS, Laskin DM (1979). PersonalityRosenfeld JP, Diaz-Clark A, Laskin DM (1983). Response to painful characteristics of patients with myofascial pain-dysfunction electrical stimulation in MPD syndrome patients (abstract). IADR (MPD) syndrome unresponsive to conventional therapy. J Dent Progr & Abstr:259. Res 58:1435-1439.Ryan W, Greene CS, Laskin DM (1985). Comparison of diazepam, Shipman WG, Greene CS, Laskin DM (1974). Correlation of placebo chlorazepate, carisoprodol and placebo in the treatment of MPD responses and personality characteristics in myofascial pain- syndrome (abstract). J Dent Res 64(Spec Iss):232. dysfunction (MPD) patients. JPsychosom Res 18:475-483.Schwartz L (1959). The pain-dysfunction syndrome. In: Disorders of Sutcher 1, Greene CS, Lerman M, Laskin DM (1969). Comparison of temporomandibular joint. Schwartz L, ed. Philadelphia, PA: W.B. pharmacologic and physical placebo therapy in TMJ dysfunction Saunders, pp. 24-43. patients (abstract). IADR Progr & Abstr: O0. 1 Downloaded from jdr.sagepub.com by guest on March 29, 2011 For personal use only. No other uses without permission.