JADA 144(9) http://jada.ada.org September 2013 979

C O M M E N T A R Y L E T T E R S

cross section of TMD patient population, as the title implies.

The authors claim that “it seems logical that efforts be directed to assess an instru-ment’s validity in discriminat-ing between patients with and without pain. ...” If pain causes restriction in the range of mo-tion or change in the speed of jaw movement as established by numerous studies, then the K6, if maintained properly, can accurately record the change. Concluding that a device is not useful on the basis of the de-vice’s inability to measure pain is unscientific.

A significant body of litera-ture in peer-reviewed journals over 40 years, including these studies,5,6 documents the effi-cacy of jaw tracking devices as valuable aids in the evaluation of TMD patients, planning ef-fective treatment and evaluat-ing outcomes. On the basis of Myotronics’ experience since 1966, Myotronics jaw tracking devices that were recognized by the ADA in its Acceptance Pro-gram7 when the program was in effect have been in successful use by clinicians in 44 countries and by 117 medical and dental schools worldwide.

Fray Adib, MBAPresident

MyotronicsKent, Wash.

1. Guarda-Nardini L, Stifano M, Brombin C, Salmaso L, Manfredini D. A one-year case series of arthrocentesis with hyaluronic acid injections for temporomandibular joint osteoarthritis (published online ahead of print April 6, 2007). Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;103(6):e14-e22. doi:10.1016/j.tripleo.200612.021.

2. Manfredini D, Bucci MB, Nardini LG. The diagnostic process for temporomandibu-lar disorders. Stomatologija 2007;9(2):35-39.

3. Manfredini D, Cocilovo F, Favero L, Ferronato G, Tonello S, Guarda-Nardini L. Surface electromyography of jaw muscles and kinesiographic recordings: diagnostic ac-curacy for myofascial pain (published online ahead of print April 11, 2011). J Oral Rehabil 2011;38(11):791-799. doi:10.1111/j.1365-2842.2011.02218.x.

4. Manfredini D, Favero L, Federzoni E, Cocilovo F, Guarda-Nardini L. Kinesiographic recordings of jaw movements are not accu-rate to detect magnetic resonance–diagnosed

ued and replaced by K7 in 2001. Dr. Manfredini has been using this 21-year-old, noncalibrated device to publish three articles since 2007 attacking the utility of jaw tracking and electromy-ography devices as aids in the diagnosis of temporomandibu-lar joint disorder (TMD).2-4

The subject study concluded that the treatment-related changes in pain levels and chewing ability in patients with monolateral temporomandibular joint osteoarthritis, receiving hyaluronic acid injections, do not coincide with changes in ki-nesiographic (KG) parameters. The authors failed to disclose having conducted a very similar study in 2007 with the same treatment protocol and nearly the same patient mix, with com-pletely different conclusions re-garding the correlation between the change in measurement of mouth opening and treatment-related changes in pain levels and chewing ability.4

Both the 2007 and 2013 studies assessed pain and chewing ability (described as mastication efficiency in the 2007 study) by means of a vi-sual analog scale. Both studies measured the mean “maximum mouth opening” (the 2007 study did not specify the measure-ment device) reported as 36.8 millimeters in the 2007 study and 35.0 mm in the 2013 study before treatment, and 42.4 mm in the 2007 study and 36.1 mm in the 2013 study after treat-ment. The 2013 study concludes that “no significant changes were described in any of the KG variables at the end of treat-ment,” even though the 2007 study had concluded that “there was a global improvement in maximum nonassisted mouth opening.”

This small study published in 2013 on 34 patients had no controls and did not investigate the use of the K6 device on a

Long D. Tieu, DDS, MScOrthodontic Graduate Student

Stephanie L. Walker, DDS, BSc

Orthodontic Graduate Student

Michael P. Major, BSc DDSOrthodontic Graduate Student

Carlos Flores-Mir, DDS, DscAssociate Professor

and HeadDivision of OrthodonticsDepartment of Dentistry

Faculty of Medicine and DentistryUniversity of Alberta

EdmontonCanada

MONITORING TM DISORDERS In Dr. Daniele Manfredini and colleagues’ April JADA article, “An Assessment of the Useful-ness of Jaw Kinesiography in Monitoring Temporomandibu-lar Disorders: Correlation of Treatment-Related Kinesio-graphic and Pain Changes in Patients Receiving Temporo-mandibular Joint Injections” (Manfredini D, Favero L, Michieli M, Salmaso L, Co-cilovo F, Guara-Nardini L. JADA 2013;144[4]:397-405), the authors used a K6 jaw tracking device manufactured by Myo- tronics (Kent, Wash.) to record the movement and speed of the jaw.

The authors’ study results are contrary to the results of other studies, including past studies by Dr. Manfredini and colleagues.1

The K6 instrument used in this study, purchased in Janu-ary 1992, was announced to owners as requiring calibration every three years. Myotronics and its Italian distributor have no record of calibration (or any type of service) since purchased 21 years ago. The authors de-scribed the K6 as “a commer-cially available device,” even though the K6 was discontin-

Copyright © 2013 American Dental Association. All Rights Reserved.

980 JADA 144(9) http://jada.ada.org September 2013

C O M M E N T A R Y L E T T E R S

TMD includes a group of disor-ders that can involve the TMJ, masticatory muscles and adja-cent structures. Therefore, no free-standing diagnostic test/device can rule in or rule out all TMDs.

The authors state, “Through the years, several technological devices have been proposed as diagnostic tools or instruments to measure treatment effective-ness.” The K6 device and others used in TMD aren’t marketed or used as stand-alone diagnos-tics. Dr. Manfredini and others have repeatedly and erroneous-ly claimed these devices have no “usefulness,” failing the sen-sitivity/specificity (rule in/rule out) test for TMD diagnostic devices.1-6 Jaw tracking devices used with EMG and TENS muscle relaxation by skilled neuromuscular dentists have proven clinical value, providing precise objective quantification of jaw movements, masticatory muscle function and occlusion prior to, during and following treatment.7,8 This usage has been recognized by the ADA.9

The authors opine that the device that measures mandibu-lar movement has no useful-ness. The accurate interpreta-tion is that reported pain and chewing function improvement after injections were not asso-ciated with significant changes in mandibular movements in 34 TMJ osteoarthritic subjects. No conclusion can fairly or ethi-cally be made about the useful-ness of computerized jaw track-ing devices from the authors’ study. The authors gratuitously and inappropriately suggest “that over-diagnosis problems are a matter of fact if TMD diagnosis relies on KG param-eters alone.”

Barry C. Cooper, DDSClinical Professor

Division of Translational Oral Biology

School of Dental Medicine

been measured objectively with surface electromyography (EMG) or a chewing force de-vice. Dr. Manfredini, who pre-viously has denied the value of EMG, didn’t measure chewing function.2

TMJ osteoarthritis can re-sult in reduced mandibular range of motion from intracap-sular damage, jaw movement pain and muscle hyperactiv-ity. The injections improved perceived pain and chewing without significant K6 man-dibular movement improve-ment. Muscle status wasn’t evaluated: “The presence of jaw muscle pain was not an exclusion criterion, provided that it was not the main source of patients’ complaints.” The authors didn’t relax muscle hyperactivity, commonly done in TMD by transcutaneous electrical neural stimulation (TENS) as documented in the literature.2

The authors wrote that TMJ disorder treatment “usually is directed toward the achieve-ment of symptom management and pain relief by means of conservative approaches. Be-cause the assessment of pain is a fundamental step in the diagnostic process as well as a target for therapy, treatment outcome measures should be based on monitoring pain symptoms.” This is an incom-plete treatment goal, which should include improvement in function and symptomatology.

Regarding criteria for TMD diagnostic devices, the authors state, “[A]ll instrumental ap-proaches to the diagnosis and monitoring of TMJ disorders should prove to be reliable for discriminating between patients with and without pain as well as for detecting changes in pain levels across time.” No measurement device can discriminate between pa-tients with and without pain.

temporomandibular joint (TMJ) effusion and disk displacement: findings from a validation study. Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114(4):457-463.

5. Cooper BC. The role of bioelectric instru-mentation in the documentation of manage-ment of temporomandibular disorders. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;83(1):91-100.

6. Weggen T, Schindler H, Hugger A. Effects of myocentric vs. manual methods of jaw position recording in occlusal splint therapy: a pilot study (Myozentrische vs. handgeführte Kieferrelation in der Okklusionsschienenther-apie–eine Pilotstudie). Zeitschrift für Kranio-mandibulare Funktion 2011;3(3):177-203.

7. American Dental Association Council on Scientific Affairs. Report on acceptance of TMD devices. JADA 1996;127(11):1615-1616.

TMD DIAGNOSTICS Dr. Daniele Manfredini and colleagues’ April JADA article, “An Assessment of the Useful-ness of Jaw Kinesiography in Monitoring Temporomandibular Disorders: Correlation of Treatment-Related Kinesio-graphic and Pain Changes in Patients Receiving Temporo-mandibular Joint Injections” (Manfredini D, Favero L, Michieli M, Salmaso L, Cocilovo F, Guara-Nardini L. JADA 2013;144[4]:397-405) is one of a series Dr. Manfredini has coauthored since 2007, appar-ently to demonstrate the lack of usefulness of computerized devices that measure physiolog-ical parameters of mandibular and masticatory function in temporomandibular disorder (TMD) patients.1-5

The authors provided five weekly temporomandibular joint (TMJ) injections with hy-aluronic acid to 34 unilateral TMJ osteoarthritis patients. The outcome evaluated changes in perceived (imprecise) sub-jective symptoms of pain and chewing ability, compared with precise measurements of man-dibular movements and veloc-ity, using a K6 EvaluationSys-tem (Myotronics, Kent, Wash.) kinesiographic (KG) mandibu-lar tracking device. The com-parisons between subjective and objective data are flawed. Chewing function could have

Copyright © 2013 American Dental Association. All Rights Reserved.