Australian Dental Journal, February, 1965 45

Temporomandibular joint dysfunction at the general practitioner level.* Part I. How to recognize

the problem

Ashley G. Hunter, M.D.S.

Introduction This article arises indirectly from a study

of occlusion by a group of general practitioners who are members of the Sydney Discussion Group. An attempt to relate clinical observa- tion to the flood of often conflicting theories in the literature brought the realization to the group that deficiencies in their know- ledge existed. The group developed a study project on the subject which has been cor- related and summarized in the present form.

This section is concerned with recognition of temporomandibular joint problems and it is believed that the best manner in which to do this is by a discussion of what is essentially a pain-dysfunction syndrome.

Pain When a patient consults you in regard to

what may eventually be diagnosed as a temporomandibular joint (T.M.J.) condition he, or more probably she,“) will give you a history consisting of pain and dysfunction mixed in varying proportions. Either may be predominant but pain, usually causing the greater inconvenience, is likely to be mentioned first.

I t is important to note the kind of pain. I t is usually described as dull, unilateral, and constant. There may be tenderness in the joint itself or it may be described as “ear ache”, “jaw ache”, “headache” or pain on chewing. The answer to the question, “Where

often too much attention is paid to the verbal answer and too little to the accompanying gestures. In answering such a question most patients will indicate with hand or Anger the site or area of pain. It makes a great deal of difference whether your patient points to a spot with one finger or moves the whole hand to a larger area. I t is likewise significant if he fixes the motion of hand or finger to one spot or an area. Furthermore, i t is significant if the pain crosses the midline o r is confined to the sensory nerve distribution of one half of the face.

Physiological pain of the kind we are considering is confined to an anatomically determined distribution and psychologically based pain is never found if the patient indicates i t by pointing to a spot, not an area, and not crossing the midline of the face.

Bilateral temporal headaches are found in patients under tension of some kind and are often the result of excessive clenching.

Dysfunction is usually manifested when the patient describes some dimculty in mani- pulating his mandible. Perhaps he will com- plain of “locking jaws”, “stiff jaw”, or com- plain of limited opening. Muscle spasm is the most common cause of limitation of movement-neoplasms, fracture, infection or rheumatoid conditions being relatively un- common, but arthroses should not be over- looked.

is your pain?” is not always understood,‘*) for Dysfunction

* Presented at the 17th Australian Dental Clicking Congress, Perth, May, 1964. 11) Schwartz, L,-Disorders of the temporomandi- ‘licking at Some point Of move-

bular joint. Philadelphia and London: W. B. ment may be mentioned and is a n annoying Saunders & Co., 1959 (P. 33).

(2) Freese, A. S., and Scheman, P.-Management and even alarlning Symptom; caused by muscle of temporomandibular joint problems. St. dysfunction it may appear and disappear Lnuis, The P . 1’. Moshy Co.. 1962 (p. 9 4 ) .

46 Australian Dental Journal, February, I965

spontaneously-sonietinies followed by pain- ful limitation of movement. From this limita- tion most patients recover with a reappearance of clicking.tS’ I t is less likely that mention of pain in areas remote from the face will be made, though these may be very significant when referred pain is being considered.

Eruxism A common complaint is of discomfort in and

about the masticatory apparatus on waking and careful enquiry may, in these cases, elicit the fact that someone has complained that the patient grinds his teeth during sleep. The patient himself is rarely aware that he does so.

History

The recording of the patient’s history should be done with care and in such a manner as to encourage him to tell his story accurately and completely. Relevant previous dental and medical experiences should be included for, as often as not, the patient will not realize that the pain in his trapezius or sterno-mastoid can be part of the dentist’s problem and he may refrain from mentioning it.

Signs

What will vou see when you examine the T.M.J. and the components of the masticatory apparatus? In a sense the physical examina- tion occurs simultaneously with the history taking, the appearance, posture, and character of bodily movement often tell you much. The patient who is under tension of some kind is all too often the one afflicted with the trouble you are attempting to diagnose. In conducting the examination remember that it is a cardinal principle to examine and compare both sides a t every step.

Extra oral Record carefully any abnormality of move-

ment when your patient opens and closes his mouth, such as deviation from the mid-line, or any joint noise, and facial asymmetry should be noted.

When examining for deviation during move- ment a valuable aid is to insert a n lnterdens between the upper central incisors and another between the lower centrals. These will act as pointers and make observation a good deal easier.

Intva ornl An abnormal pattern of occlusal wear is a

frequent sign of occlusal and possibly asso- ciated T.M.J. problems. Comparative lack of wear is an aspect sometimes overlooked in this regard, but it is as important as excess wear(*) and isolated loose teeth without perio- dontal cause are significant.

Patterns of closure from rest position to complete closure must be studied, noting care- fully areas of premature contact which can be a direct cause of T.M.J. trauma, thereby setting in train associated symptoms, or pos- sibly, the trigger areas for the bruxism causing wear and further T.M.J. trauma.

Occlusal interference Occlusal interferences, which of course

includes the very important premature con- tacts, can be detected directly or indirectly.

Direct: Recording of interferenres can be achieved best by the use of a material of which the patient is least aware. For this purpose 30 gauge casting wax or K e r r Occlusal Indicator wax is used. Cut into strips and moulded over the lower teeth the patient comes into the first contact position and the pre- mature contacts will cause perforations easily seen in the wax.

Indirect: The method of indirect registration of centric occlusion”’ uses plaster injected between the cheek and teeth, in centric occlu- sion (Fig. 1). Cheek pressure will mould the plaster against the teeth. These plaster indices are trimmed and used to mount stone casts on a grooved platform. With the casts thus mounted, interferences can be seen and by sliding the models from and toward each other the effect on the mandible can be visualized (Fig. 1). This can supplement the ohserva- tions made during the physical examination, and this technique can be used to evaluate the complexity of treatment by grinding and allow development of the essential plan necessary before grinding is undertaken.

C u s f i d protection : When searching for occlusal interferences or premature contacts care must be taken to recognize that type of occlusion in which the cuspids are the only teeth in contact during lateral movement, but are out of contact in centric, and come into

(4) Hirt. H. A,, and Muhlemann. H. I<.-Diagnosis of bruxism by measurement of the tooth mobility. Paradontal.. Zurich. 9 : 47, ’ 1955 ; abstracted D. Abs. (June) 1956.

Qchwartz. IA.--fJ/J. ri t . (1). 1 4 I ) .

Australian Dental Journal, February, I965

play with the premolars in protrusive move- ment. This is the cuspid protected occl~sion.(~)(~)

In 1958 D’Amico presented his theory of cuspid function which, briefly, is:

( 1) Periodontal proprieceptive impulses from cuspids coordinate neuro-muscular function. A most important aspect of T.M.J. problem as will become apparent later.

( 2 ) The cuspids guide other teeth into centric occlusion.

(3) By their morphology they are adapted to stress, and prnteet o t b r teeth.

( 4 ) They lessen horizontal vectors of force whirh, of course, are the most traumatic.

4 7

Fig. 1.-The indirert fegistration of centric occlumon.

This type of occlusion is absolutely normal in many mouths and grinding the cuspids will not help solve the patient‘s problem. Always remember a n occlusion is to function for the patient-not to please the dentist.

Every dentist knows the problem of obtain- ing a “normal” bite registration and it is no easier in this T.M.J. work than any other. Many of the patients are in pain, anxious, and

‘“I D’Amico. A.-Canine teeth-normal functional relation of the natural teeth of man. J. South. California D.A., 2 6 : 6-23 (Jan.) : 49-60 (Feb.) ; 127-142 (Apr.) 239-241 (July) 1958.

(7) D’Amico, A.-Application of the concept of functional relation of the canine teeth. J. South. California D.A., 2 7 : 39-58 (Beb. ) 1959.

though trying to cooperate, require assurance and patience if their tension is not to cloud results.

Function In searching for factors possibly precipi-

tating muscle spasm and pain, enquiry will have elicited information from the patient, on habits, perhaps associated with work, e.g., holding upholstery tacks between the teeth or perhaps in play, when clenching is pre- cipitated. conimonly enough, by the tension of competition.

There is a wide difference between the possible effects of (1) occlusal stresses exerted during eating-referred to as functions, and ( 2 ) occlusal stresses exerted other than by eating-referred to as parafunctions.(8’

The distinction is made because during function reflex coordination and tactile control serve a s self-protecting mechanisms. The sort of thing that happens when you unexpectedly make contact with a hard object in food is a n extreme example, but none the less illustra- tive of the oft repeated action, in a lesser key certainly, precipitated by perhaps a premature contact.

During parafunctions, however, the mas- ticatory system is not protected by such mechanisms. Occlusal stresses, outside nornial functions, are thought, by many authorities, to be a major cause of T.M.J. trauma and muscle spasm with its related cyclical sequelte of pain and disturbed function.

These parafunctions fall into fairly clear cut categories.

(1) Bruxism, essentially nocturnal, and rarely known to the patient, is usually indicated by an abnormal degree of wear and a history of general unease about the mouth on waking.

( 2 ) Clenching occurs during waking hours and is the result of tension.

(3) Habitual, such as pipe smoking, chewing pens or other objects, and occupational such as holding objects used in work between the teeth.

( 4 ) Compensating. Occlusal interference, sometimes brings about excessive compensating parafunctions when there are involuntary and unconscious reactions to occlusal inter- ference, perhaps in a n attempt either to avoid or remove some point of occlusal inter-

( 5 ) Lipke, D , and Posselt. U.-Panel discussion. Royal Dental School, Malmo, Sweden. J. West Soc. Periodont, X : 4. 4 X - . j X (.June) 1960

48 Australian Dental Journal, February, 1965

Pain 01 local origin: The symptoms are essentially pain, swelling,

muscle spasm, and limitation of movement, so that history, clinical and X-ray examinations will usually sufece for a diagnosis. These

ference. Major trauma to the T.M.J. such as fracture, severe dislocation or sprain can be responsible for a n arthrosis of the joint but are not as important as continued trauma of a lesser nature in contributing to the later

i

Fig. S.-I’alpation of the condyle. ( Schwartz, L.-Disorders of the temporomandibular joint. Phila- delphia, W. €3. Saunders Com-

pany, 1969.)

development of degenerative joint disease. These latter arise from persistent masticatory malfunctions.

Differential diagnosis of pain Pain is the disturbance which most often

causes patients to seek treatment. They are often unconcerned about and indeed may be unaware of clicking and other functional dis- turbances of the joint.

The pain may be (1) of local origin, (2 ) referred, (3) psychogenic or neurogenic.

Fig. 3-I’alpation of the masseter and the internal pterygoid muscles. (Schwartz, L.-Disorders of the temporo- mandibular joint. Philadelphia, W. B. Saunders Company,

1 9 5 9 . )

symptoms may also be produced by a traumato- genic occlusion, which will be seen on clinical examination.

Referred pain: The temporomandibular joint is a common

site of referred pain. Obviously it is essential that such pain be differentiated from pain of local origin. Pain referred here can be pro- duced by muscle spasm and by myofascial

Australian Dental Journal, February, I965

trigger areas, which can of themselves also produce muscle spasm. The masseter muscle is by fa r the commonest site of referred pain and when this condition is present there is always some mandibular dysfunction. The mandibular dysfunction will appear either as a trismus of varying degrees, or a midline deviation of the mandible on opening, or a t any point of closing.

Palpation will reveal spasm or trigger areas, with referral of pain to the temporomandibular joint. Since myofascial trigger areas will produce deep tenderness in their zones of reference, the joint may exhibit tenderness even though there is no pathosis present and detection of tender areas within muscles will be most helpful in reaching a diagnosis.

Reference to the illustrations will show the technique of palpation for the areas of interest in the diagnosis of T.M.J. disorders. Figure 2 shows palpation of the lateral aspect of con- dyle, of the distal aspect with jaw open, and of the distal aspect through the auditory meatus. During opening, if there is no for- ward movement of the condyle, rotation of the condylar head may be felt by the palpating Anger. With forward movement the condylar head leaves the Anger.

Figure 3 shows palpation of the superficial portion of the masseter whilst probing for painful areas with forefinger of the other hand, of the origin of the internal pterygoid, and of the insertion of the internal pterygoid.

Figure 4 shows palpation of the two internal pterygoid muscles simultaneously, of the origin of the temporal muscle, and of the origin of the inferior head of the external pterygoid muscle. Myofascial pain: The dentist who is interested

in either the T.M.J. (merely a junction between two bones) or the temporomandibular articula- tion which includes not only the joint, but all those structures which play a part in the function of the joint, will And myofascial trigger mechanisms one of his most important clinical pr~blerns.‘~’ In fact, i n many cases it will be the most important clinical entity he encounters within the whole group of dys- functions located in both the joint itself, and the muscular elements of the total articulation. Myofascial pain is the term applied to those pain syndromes originating in myofascial

49

(8) Travel], J.. and llinzler, 8. H.-Scientific ex- hibit : myofascial genesis of pain. Postgrad. Med., 11 : 435-434 (May) 1952.

structures whilst the myofascial trigger area(1o’ is a small, circumscribed, very hypersensitive area in myofascial tissues from which impulses arise to produce referred pain. This area exhibits deep hyperalgesia, it is a physical sign, not a symptom, and the patient is usually unaware of it. Palpation as previously illustrated will frequently disclose these areas.

Big. 4.-I’alpation of the internal pterygoid, temporal, and external pterygoid muscles. (Schwartz, L.- Disorders of the temporomandibular joint. Philadelphia, W. B. Saunders

Company 1959.)

Zone of reference: This is the region irr which pain, hyperalgesia or muscle spasm are. produced by a myofascial trigger area. Patients can localize referred pain with surprising accuracy. Some zones of reference of myo- fascia1 trigger areas in the neck and head muscle, of interest to the dentist, are shown. Figure 5 shows the trigger area in the joint and pattern of referred pain. F’igure 6 shows

110) Freese, A. S.-The temporomandibular joint and myofascial trigger a reas in the dental diagnosis of pain. J.A.D.A.. 5 9 : 448-458- (Rept.) 193!,.

50 Australian Dental Journal, February, I965

trigger area in temporal, masseter and sterno mastoid with related areas of referred pain.

Many muscles have the temporomandibular joint and the ear as zones of reference and almost all of these muscles have some part of the total temporomandibular articulation as a zone of reference.

It is possible for the non-painful symptoms to be the significant ones. For example, the muscle spasm may lead to an apparent shorten- ing of the muscle with limited motion and

Fig. 5.-Trigger area in the joint and the pattern of referred pain. (After Travell, J . , and Rinzler. S. H. Postgrad. Med., 1 1 : 425-

4 2 7 , 1 9 5 2 . )

weakness ; however, once the myofascial trigger mechanism is blocked, the muscle returns to normal. Possibly the most dramatic and alarming condition produced by these muscle spasms is the patient’s inability to open his mouth normally ; opening is sometimes limited to as little as a few millimetres. Blocking the trigger mechanism will restore the muscles to normal and thus will allow the degree of opening to return to normal.

Activating stimuli: The myofascial trigger area can be activated(ll) by: (1) any motion that stretches the structure containing the trigger area, ( 2 ) needling, (3) pressure, ( 4 ) intense heat or cold, ( 5 ) prolonged cooling.

The dentist should note that routine pro- cedures, such as having the patient open his mouth (which involves the stretching of a number of myofascial structures) and ad- ministering a local ansesthetic (which involves needling) may activate dormant myofascial trigger areas. Consequently, the appearance of an active myofascial trigger mechanism following routine dental procedures does not necessarily mean that the practitioner has produced it, only that he may have activated a dormant condition.

WB?mMlS YASSITER STEIlCWUSTOIO

X TRIGGER AREA

-r! PAIN PATTERN

Fig. 6. - and the referred

S. H.

-Trigger itrrii in the trniporal. niassetet sterno-mastoid iiiuwlrs. with area of pain. (After Trawll , J. , and Rinaler, Postgrad. h l t d . . 11 : 42 .5 -42 i , 1952. )

Amongst a long list of predisposing causes given by Travell in myofascial trigger areas, is sudden trauma to musculoskeletal structures.

We have now reached the point where it is apparent that T.M.J. problems can arise from a number of interrelated sources and that the reaction of the activating musculature to certain stimulus can cause pain of both local and referred character.

Muscle spasm brought about, perhaps by abnormality of occlusion, will cause both pain and limitation or variation of movement, which in turn will probably worsen the whole situation.

Pain in the joint region itself may be due to local pathosis, but the joint may be the site of referred pain from a myofascial trigger area-which in turn can frequently be detected by palpation. Many authorities use the stethoscope for detecting abnormal joint sounds, if present, in differential diagnosis and with practice, much information about

111) Freese, A. S., and Schenian, P.-Op. cit . (p. 1 1 9 ) .

Australian Dental Journal, February, I965

the condition of the joint can be obtained by this means.

Pain is sometimes referred to the ears and a rough and ready differential diagnosis can be made by gently pulling outward and back- ward on the ear-if pain occurs the otitis externa is suspected, if not it may well be pain referred from the joint or a myofascial trigger area.

5 1

In discussion of this section, 1 have de- liberately refrained from introducing special diagnostic procedures and aids such as electro- myographic recordings, and tomography be- cause they are outside the scope of the average general practitioner.

143 Macquaiie Street. Sydney.

InLayinntzott One of the corner-stones of modern science is the discovery by Friedrich von Kekute that the molecules of the basic organic compounds do not consist of strings of atoms as was previously believed, but from closed chains or loops. He made this discovery while he was sitting half asleep in front of the fire, and as a kind of hallucination. He saw strings of atoms “all twining and twisting in snake-like motion. But look, what was that? One of the snakes had seized hold of its own tail. . . . As if by a flash of lightening I awoke. Let us learn to dream, gentlemen”.

The snake swallowing its tail was a kind of optical pun on the closed ring of atoms. Michael Faraday, one of the greatest physicists of all time. saw the stresses surrounding magnets and electric currents as curves in space, which in his imagination were as real as if they had consisted of solid matter. He called them “lines of force”, and he visualized the universe patterned with these lines. It was this vision that gave birth to the electro-magnetic theory of light. Kekute’s hallucinated serpents remind one of paintings by Blake. The curves of force which crowded Faraday’s universe recall the vortices in Van Gogh skies.-Arthur Komtler, ThPhe Lis tmw, May 28. 1964.