Ann. rheum. Dis. (1969), 28, 139

TEMPOROMANDIBULAR JOINT IN ADULTRHEUMATOID ARTHRITIS*

A COMPARATIVE EVALUATION OF 100 CASESBY

A. S. T. FRANKSDepartment of Dental Prosthetics, University of Birmingham Dental School

As emphasized by Uotila (1964), medical interestin the stomatognathic system of patients withrheumatoid arthritis has been mainly concerned withthe theories of focal infection. In recent years theseconcepts have become less commonly accepted andthe interest accordingly reduced. However, thetemporomandibular joints may be consideredamongst the more important of the body and apractical clinical consideration of their reaction tosystemic disease is an obvious requirement.The knowledge that rheumatoid arthritis affects

the temporomandibular joint has been on recordfor a number of years, but the reported incidenceof manifestations in this joint vary greatly in theliterature (Table I). The majority of previousstudies have dealt with relatively small numbers ofpatients.

TABLE IREPORTED INCIDENCE OF TEMPOROMANDIBULARJOINT INVOLVEMENT IN RHEUMATOID ARTHRITIS

Author Date Incidence per cent.

Ragan 1949 4-7Markowitz and Gerry 1949 8-7Hankey 1963 10Hartfall and Wright 1961 19Einaudi and Viara 1964 29*3Meriel, Ruffie, Cadenat,

Fourni6, and Blanc 1960 31Uotila 1964 41Russell and Bayles 1941 51Blanc 1959 56Blackwood 1963 70

The present study was designed as a survey of anunselected group of patients with confirmed rheuma-toid arthritis to determine the frequency and charac-teristics of lesions of the temporomandibular joint.Comparison has been made with control groups toevaluate the possible clinical significance of thefindings, and with patients complaining of the

*The substance of this article was reported to the Heberden Societyon November 12, 1965.

"temporo-mandibular joint pain-dysfunction syn-drome" as previously investigated and described(Franks, 1964).

MethodThe hundred unselected patients in this study were

attending the day clinic at the Arthur Stanley Institutefor Rheumatic Diseases, London, and had been con-firmed as cases of rheumatoid arthritis. After aninterview to a standard questionaire, the temporo-mandibular joints and their environment, which includesthe oral cavity, were examined by the author. Assess-ment of the general index of rheumatoid arthritis wasundertaken by a rheumatologist (Dr. B. Watkin).

Radiological assessment was made by standard lateraloblique film. Where doubt existed, that is there waspositive clinical evidence but negative radiologicalfindings, tomograms were taken of the temporomandibu-lar joints.When the age-sex distribution of the patients was

known-at the termination of the study-three controlgroups of 100 randomly selected patients were formedmatched for age and sex with the rheumatoid group.

Control Group "A"-a hundred selected from 590non-regular attenders for dentaltreatment (i.e. less than twice ayear).

Control Group "B"-a hundred selected from 326regular dental patients.

Control Group "C" a hundred selected from 900patients who attended the au-thor's temporomandibular jointclinic with an acquired abnorma-lity classified as "temporomandi-bular joint pain-dysfunction syn-drome". This is a non-destruc-tive abnormality of functionmainly concerned with the masti-catory muscles (Franks, 1965).

The data were analysed for degrees of significanceusing the x2 test.

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ANNALS OF THE RHEUMATIC DISEASES

ResultsAge-Sex DistributionThe male : female ratio of the patients examined

was just under 1 : 3. The age range of both sexeswas comparable (Fig. 1). No patient was under theage of 25 and the majority were over 55.

Temporomandibular JointsSome history of temporomandibular joint dis-

order (i.e. pain, noise within the joint or movement,altered function of the joint) was discovered in 53per cent. of the rheumatoid group. No patientcould antedate this local complaint before their otherjoint symptoms. Clinically 40 per cent. of therheumatoid patients had palpation tenderness of thetemporomandibular joints, and 63 per cent. hadcrepitus in at least one of the moving jaw joints.These results are displayed with the appropriatecontrol figures in Table II.From Table III it can be seen that patients with a

history of temporomandibular joint disorder weremore likely to have crepitus and change in thetemporomandibular joints. However, the historywas of no significance in relation to the radiologicalfindings, which disclosed that 56 per cent. hadstructural changes of the calcified joint tissues. It

50

40 *

6)0'30 A

TABLE IIIHISTORY OF TEMPOROMANDIBULAR JOINTDISORDER RELATED TO JOINT CHANGES

IN 100 RHEUMATOID PATIENTS

History of Temporomandibular Present Absent TotalJoint Disorder 53 47 100

Crepitus..38 25 63Radiological Change .. 31 25 56

was found (Table IV) that, where crepitus waspresent in the moving joint, there was a highly sig-nificant incidence of radiological positives: 43 out of63, as opposed to 13 out of 37 in which crepituswas absent.

TABLE IVCREPITUS IN THE JOINT RELATED TORADIOLOGICAL EVIDENCE OF CHANGE

Radiological ChangeCrepitus No. of Cases in Joint

Present 63 43

History of Joint 15 4Disorder 1 1

Absent 37 13No History of J _

Joint Disorder 22 9J

Total Rheumatoid Patients 100 56

TABLE IISIGNS AND SYMPTOMS OF TEMPOROMANDIBULAR JOINT DISORDER IN PATIENTS WITH

RHEUMATOID ARTHRITIS AND THREE CONTROL GROUPS

Group

History of Temporomandibular Joint DisorderTenderness of Temporomandibular Joint

(Palpation) ..Crepitus in moving Temporomandibular Joint

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TEMPOROMANDIBULAR JOINT

Some evidence of temporomandibular jointdisturbance, clinical or radiographic, was presentin 86 per cent. of the rheumatoid patients.

Oral HealthThis was almost uniformly poor, 86 per cent. being

dentally unfit.Only six of the patients attended for regular dental

treatment, so that as a group they are directlycomparable, in terms of dental health, with Controlseries A.However only 51 per cent. of the rheumatoid

patients had some natural teeth, and this causeshesitation in comparisons with the control groups inwhich the proportion was much higher. Particularlyis this so if we attempt to consider the possiblechanges in temporomandibular joint function broughtabout by partial loss of natural teeth.

However, if one takes this group of 51 per cent.with natural teeth and examines, those within it whohave temporomandibular joints affected by rheuma-tism, one finds ninety per cent. with unreplaced miss-ing teeth with an average of eight missing and thatthis is not significantly different from the controlseries A (Table V).

Further, if we consider unbalanced tooth loss-between the two sides of the mouth, the x2 testagain shows no significant difference between therheumatoid group and Control A. In addition,57 per cent. of those with natural teeth (i.e. 25 of the44 rheumatoid patients) had some radiologicalchange, compared with 55 per cent. of those withfull dentures (i.e. 23 of the 42 rheumatoid patientswith full dentures)-no significant difference. Inview of these findings, it was thought justified-inthis investigation-to consider the patients withnatural and artificial teeth together.

Previous studies of temporomandibular jointdisorders at the Institute of Dental Surgery haveindicated (Franks, 1967) the apparent aetiologicalimportance of certain functional habits-particu-larly that associated with unilateral chewing. The

importance of this factor appears to be underlinedyet again in the disorder under current investigation(Table VI). Here the incidence of the habit amongstthe rheumatoid patients with temporomandibularinvolvement shows a significant relationship.

TABLE VICHEWING HABIT RELATED TO INCIDENCE OF

RHEUMATOID ARTHRITIS IN TEMPOROMANDIBULARJOINT

Rheumatoid ControlsGroup Arthritis ofGroup Temporomandibular

Joint A B C

Unilateral ChewingHabit (per cent.) 69 50 43 82

Radiological FindingsChanges appear to occur first in the anterior

margin of the condyle (Fig. 2). Progressively the

Fig. 2.-Right temporomandibular joint in closed position. Tomo-gram showing early rheumatoid change. The radiolucent area is

seen in the anterior part of the condyle.

TABLE VDENTITION IN 86 PATIENTS WITH RHEUMATOID ARTHRITIS OF THE TEMPOROMANDIBULAR JOINT

AND CONTROL GROUPS

Rheumatoid Controls- Group Arthritis of

TemporomandibularJoint A B C

Per cent. with some natural teeth 51 80 84 92

Per cent. with unreplaced missing teeth 90 88 69 76

Dentition Average number of missing teeth(per person) 8 9 7 7

Per cent. with tooth loss unbalancedbetween two sides of mouth 73 66 52 86

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ANNALS OF THE RHEUMATIC DISEASES

destruction causes the condyle to resemble the"sharpened pencil deformity" of the phalanges (Fig.3) (Simon, 1965). Uotila (1964) suggested itslikeness to "the mouth-piece of the flute". In themost severe manifestation the condyle is completelyobliterated (Fig. 4), but function may still remainsatisfactory; the patient illustrated in Fig. 4 couldopen his mouth 44 mm. (the normal average) andhad in fact no history, no crepitus, no symptoms.

General Rheumatoid StatusIn each of the rheumatoid patients, the number

of joints involved in the arthritic process was listedby Dr. Watkin. Small and large joints were collatedseparately (Table VII). 38 per cent. of the groupwith between four and seven small joints affectedand 53 per cent. of those with over eight smalljoints affected had involvement of the temporo-mandibular joints, but the incidence is not significant.The number of large joints involved, however, issignificant; as the number increases so does theincidence of temporomandibular trouble.

TABLE VilRHEUMATOID ARTHRITIS IN TEMPOROMANDIBULAR

JOINTS RELATED TO SYSTEMIC JOINTINVOLVEMENT 4

Systemic Manifestations ofRheumatoid Arthritis

(Joints involved)

Up to 3Small 4-7

Over 8

Up to 3Large 4-7

Over 8

RheumatoidArthritis of

TemporomandibularJoint (per cent.)

0

3853

355878

Fig. 3.-Right temporomandibular joint in open position. Standardradiograph showing results of progressive destruction of condylehead, leading to an appiaiance similar to "the mouth-piece of a flute."

Fig. 4.-Right temporomandibular joint in closed position. Tomo-gram showing severe destruction of condyle and condylar neck in

rheumatoid arthritis. The condyle is completely obliterated.

Functional incapacity was graded according toSteinbrocker, Traeger, and Batterman (1949).Table VIII shows that the highest incidence oftemporomandibular joint disturbance occurs in themore severe cases of rheumatoid arthritis. Theassociation of the progressive percentage increase inaffection of the temporomandibular joint withincreasing functional incapacity is significant initself. A significant percentage of the patientsexamined showed only moderate systemic manifes-tations of rheumatoid arthritis.

TABLE VIIIFUNCTIONAL INCAPACITY OF PATIENTS WITH

RHEUMATOID ARTHRITIS OF TEMPOROMANDIBULARJOINTS

Patients with RheumatoidFunctional Rheumatoid Patients Arthritis ofIncapacity Studied (Percentage Temporomandibular Joint

(Steinbrocker and incidence within (Percentage incidenceothers, 1949 whole group) within each

"incapacity group")1 4 33

Il 51 41III 40 60IV 5 70

Analysis of the age at onset of the rheumatoidcondition (Table IX, opposite) and of the erythro-cyte sedimentation rate revealed no significant re-lationship.

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TEMPOROMANDIBULAR JOINTTABLE IX

RELATIONSHIP OF AGE AT ONSET OFRHEUMATOID ARTHRITIS AND LESIONS IN THETEMPOROMANDIBULAR JOINT (PER CENT.)

Age at Onset (yrs) 15-24 25-34 35-44 45-54 55-64 65 +

RheumatoidArthritis of 82 71 66 79 33 50

TemporomandibularJoint

Haemoglobin averages (at least five per patient)showed a significantly higher incidence of temporo-mandibular joint involvement amongst those witha reduced haemoglobin level (Table X).

TABLE XHAEMOGLOBIN LEVELS (AVERAGE OF AT LEASr

5 ESTIMATIONS PER PATIENT) RELATED TORHEUMATOID ARTHRITIS OFTEMPOROMANDIBULAR JOINT

Rheumatoid Arthritis ofHb Temporomandibular Joint(per cent.) (per cent.)

*80 and over 59

under 80 77

DiscussionClinical FindingsThe age-sex distribution of the patients under

discussion agrees closely with the average patternsassociated with the complaint in the general popu-lation (Kellgren, Lawrence, and Aitken-Swan, 1953),so that there is some justification for drawing generalconclusions from the results.

Previously published work (Table I) has shown avarying incidence of rheumatoid temporomandibularjoints. The study of Blackwood (1963) is ofespecial importance because it is based on autopsyfindings, seven of his cases of rheumatoid arthritisdemonstrated temporomandibular joint changes,and although the group is small his results are themost objective.A question which requires further evaluation is

whether the incidence of temporomandibular jointdisorder is increasing. A comparable suggestionhas been made for the hip joint (Edstrom, 1961),the explanation being based on an osteoporosisfollowing the use of steroids and the resultant abuseof damaged joints freed from pain.

In dealing with disease of the temporomandibu-lar joint, it is important to be aware of the diagnosticproblems associated with it (Franks, 1964) and thealmost epidemic nature of non-destructive temporo-mandibular joint dysfunction (Table III). Thecontrol studies disclosed an incidence of 24 and 19per cent. in the two groups.

Certain differential characteristics of the rheuma-toid temporomandibular joint are clearly shown bythe results of the study. Tenderness is significantlymore frequent over the rheumatoid joint, but in thedysfunction cases the masticatory muscles are morefrequently involved.

Crepitus appears to be of considerable significance,when it is present irreversible degenerative change islikely to have taken place, but structural changemay occur without crepitus-a result, perhaps, ofremodelling of the articular surfaces without carti-lage loss and fragmentation.

Table VIII suggests that involvement of thetemporomandibular joint by rheumatoid arthritis isnot an index of the severity of the systemic mani-festations.

Since this paper was presented to the HeberdenSociety in 1965, rheumatoid arthritis of the temporo-mandibular joint has been discussed by Marbachand Spiera (1967) in a resume of two cases whichincludes general conclusions that cannot be suppor-ted. For example, they suggest that in rheumatoidarthritis there is a considerable reduction in theamount of possible condyle movement during mouthopening. Table XI clearly shows that there is onlya slight reduction in the amount of opening (asmeasured between maxillary and mandibular in-cisors) and mandibular condyle movement which isof little significance.

TABLE XIFUNCTION OF TEMPOROMANDIBULAR JOINT

IN RHEUMATOID ARTHRITISExpressed as Degree of Mandibular Condyle Movement

measured by Maximum Inter-incisal Opening

Group Inter-incisal Opening(mm.)Patients with Rheumatoid Arthritis

of Temporomandibular Joint 38-0

A 43 -5

Controls B 45 *0

C 32-0

Functional AspectsAmongst the unique characteristics of the tem-

poromandibular joints is the fact that the joint ateach end of the mandible is one half of a functionalunit. One joint cannot operate independently andtherefore any alteration in the activity of one sidewill affect the other. Clearly a unilateral chewinghabit constitutes an uneven distribution of functionbetween the right and left joints. Previous work(Franks, 1967) has indicated that such a habit is ofconsiderable importance in the aetiology of temporo-mandibular joint pain-dysfunction. The significantincidence of abnormal jaw function amongst rheumatoid patients is striking.

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ANNALS OF THE RHEUMATIC DISEASES

It would be legitimate to ask which came first,the deranged activity or the joint disease. Theresults indicate that the patient's awareness of atemporomandibular joint disorder (i.e. history) wasnot significant in relation to the incidence of radio-logical change. Furthermore it was found that theaverage joint movement measured as maximalmouth opening without pain in the rheumatoidpatients was reduced but not significantly (TableXI). This would suggest that the functional effectof rheumatoid arthritis on the joint was not signifi-cant and that the significant incidence of unilateralchewing was not a result of the joint changes butmore probably a precursor.

SummaryThe examination of 100 patients with rheumatoid

arthritis has shown that the temporomandibular jointcan become involved at varying stages of the naturalhistory of the disease, and that such signs andsymptoms are much more common than previouswork has suggested. The more severe the mani-festations of the general complaint, the more

commonly are the temporomandibular joints in-volved; however, the involvement of these joints isnot itself an index of the severity of the systemicmanifestations.

Bywaters (1962) posed a fundamental question,"What determines the localization of rheumatoidarthritis in a joint?", and suggested that movementitself, or perhaps the mild trauma which occurs withmovement, may be responsible for the localizationof the inflammatory agent. The present study showsthat this concept may be applied and extended; theappearance of rheumatoid changes in the temporo-mandibular joint may be related to an unevendistribution of function between the right and leftsides.

I am indebted to the Medical Research Council fortheir support during the period that the above work wascarried out. I should also like to express my thanks toDr. Oswald Savage, not only for allowing me access tohis patients, but for the spirit in which his co-operationwas offered. I am also very grateful to Dr. BernardWatkin for his valuable help and assistance in thesystemic assessment of the rheumatoid patients.

REFERENCESBlackwood, H. J. J. (1963). Brit. dent. J., 115, 317 (Arthritis of the mandibular joint).Blanc, P. (1959). Cahiers odontostomat., 9, No. 3-4, p. 17 (L'atteinte de l'articulation temporo-

maxillaise au cours du rhumatisme inflammatoire chronique).Bywaters, E. G. L. (1962). "Inflammatory Polyarthritis", in "Conference on the Causes and

Treatment of Rheumatic Diseases, 1962," p. 15. (1st Nuffield Conference on Rheumatology.)Nuffield Foundation, London.

Edstr6m, G. (1961). Acta rheum. scand., 7, 151 (Destructions of hip joint in rheumatoid arthritisduring long-term steroid therapy).

Einaudi, G., and Viara, M. (1964). Reumatismo, 16, 341 (I1 comportamento dell' articolazionetemporo-mandibolare nei pazienti affetti da artrite reumatoide).

Franks, A. S. T. (1964). Dent. Practit., 15, 94 (The social character of temporomandibular jointdysfunction).

(1965). J. pros. Dent., 15, 1122 (Masticatory muscle hyperactivity and temporomandibularjoint dysfunction).

(1967). Brit. J. oral Surg., 5, 157 (The dental health of patients presenting with temporo-mandibular joint dysfunction).

Hankey, G. T. (1963). Brit. dent. J., 115, 324 (Discussion of "Arthritis of the mandibular joint").Hartfall, S. J., and Wright, V. (1961). "Manifestations of Rheumatoid Arthritis". Reckitt & Sons,

Hull.Kellgren, J. H., Lawrence, J. S., and Aitken-Swan, J. (1953). Ann. rheum. Dis., 12, 5 (Rheumatic

complaints in an urban population).Marbach, J. J., and Spiera, H. (1967). Ibid., 26,538 (Rheumatoid arthritis of the temporomandibular

joints).Markowitz, H. A., and Gerry, R. G. (1949). Oral Surg., 2, 1309 (Temporomandibular joint disease).Meriel, P., Ruffie, R., Cadenat, H., Fournie, A., and Blanc, P. (1960). J. Radiol. tiectrol., 41, 105

(Exploration radioclinique de l'articulation temporo-maxillaire).Ragan, C. (1949). J. Amer. med. Ass., 141, 124 (The general management of rheumatoid arthritis).Russell, L. A., and Bayles, T. B. (1941). J. Amer. dent. Ass., 28, 533(Thetemporomandibularjoint

in rheumatoid arthritis).

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TEMPOROMANDIBULAR JOINT

Simon, G. (1965). "Principles of Bone X-Ray Diagnosis", 2nd ed., p. 168. Butterworths, London.Steinbrocker, O., Traeger, C. H., and Batterman, R. C. (1949). J. Amer. med. Ass., 140, 659 (Thera-

peutic criteria in rheumatoid arthritis).Uotila, E. (1964). Acta odont. scand., 22, Suppl. 39 (The temporomandibular joint in adult rheuma-

toid arthritis).

L'articulation temporo-maxillaire chez l'adulte atteint depolyarthrite rheumatoIde

RfSUMmL'examen de cent malades atteints de polyarthrite

rhumatoide a demontre que I'articulation temporo-maxillaire peut etre affectee aux differents stades de lamarche normale de la maladie et que ces signes cliniqueset ces symptomes sont beaucoup plus communs que lestravaux ant6rieurs avaient sugger6. Plus les manifesta-tions de la maladie en general sont serieuses plus il estcommun de voir les articulations temporo-maxillairesaffectees; l'affection de ces articulations n'est pas d'elle-meme un indice de la sev6rite des manifestations syste-miques.Bywaters (1962) a pose une question fondamentale,

'Que'est-ce qui d6termine la localisation de la poly-arthrite rhumatoide dans une articulation?" et a suggereque le mouvement lui-meme, ou peut-etre le traumatismeleger qui a lieu pendant le mouvement, pourrait etreresponsable de la localisation de l'agent inflammatoire.Cette etude demontre que ce concept peut etre appliqueet etendu, l'apparition des changements rhumatoidesdans l'articulation temporo-maxillaire peut se rapportera une distribution in6gale des fonctions entre le c6tedroit et le c6te gauche.

La articulaci6n temporomaxilar en adultos con poliartritisreumatoide

SUMARIOEl examen de 100 pacientes con poliartritis reumatoide

ha revelado que la articulaci6n temporomaxilar puedequedar afectada en diferentes etapas del desarrollonormal de la enfermedad, y que tales manifestaciones ysintomas son mucho mas comunes que lo que hansugerido trabajos previos. Cuanto mas severas lasmanifestaciones de la enfermedad general, tanto mascomunmente afectadas las articulaciones temporo-maxilares; no obstante, la complicacion de estas articu-laciones no es un indice de la severidad de las manifesta-ciones sistemicas.

Bywaters (1962) plante6 una cuestion fundamental:", Que es lo que determina la localizaci6n de la poliartritisreumatoide en una articulaci6n ?", y sugiri6 que elpropio movimiento o quiza el ligero trauma que ocurrecon el movimiento seria tal vez el causante de la locali-zaci6n del agente inflamatorio. Este estudio muestraque el concepto podria ser aplicado y ampliado, y laaparici6n de cambios reumaticos en la articulaci6ntemporomaxilar pudiera ser atribuida a una distribuci6ndesigual de las funciones entre los lados derecho eizquierdo.

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