Temporomandibular joint disease

ORAL

SURGERY, and ORAL

Quarterly

ORAL

MEDICINE

PATHOLOGY

Review of the Literature Associale Edilor TIIOMAS

J. COOK

Corresponding

Editors

AUSTRALIA A. J. Amott Sydney, Australia

ITALY Alexander G. Nutlay Halifax, Nova Scotia

CENTRAL AMERICA Claudio Funcia Cornell Havana, Cuba

SCANDINAVIA Reidar F. Sognnaes Belmont, Mass.

SOUTH AMERICA Guillermo A. Ries Centeno Buenos Aires, Argentina ENGLAND Paul A. To&r St. Albans, England

OCTOBER,

Collective TEMPOROMANDIBULAR

SWITZERLAND AND Erik P. Steinmann lians Miihlemaun Raoul H. Boitel Ziirich, Switzerland

GERMANY

1949

Review JOINT DISEASE

Secti,on I. Statistical Evaluation of Temporomandibular Disease TER~POROY~NDIBUL~R

Amm~~I~x.~s

The Problem.Introduction.-The purpose of this project has been to arrive at a system of diagnosis for the various arthralgias affecting the temporomandibular articulation and to evaluate t,he various forms of therapy which may be used in their treatment. It was felt that any attempt to carry out this aim should include, so far as is possible, a thorough review of t)he anatomy, physiology, radiology, histology, and pathology of this area. The literature, from very early times, contains a wealth of information, some of which is very questionable, on this subject. There are a number of Research Project So. X-‘ifi (Cm. lSO), United States Navy. The opinions contained in this article are those of the writers alone and do not necessarilY reflect the attitude of the Navy Uepartment. *Commander, M.C., United States Navy. **Commander, D.C., United States Navy.

Normal occlusion Closed-bite Open-bite Loss of lateral excursion 12dentulous

T.41312

ILL.

,~l)I)Il’lOXAl,

I’MiTISk:NI’

(~ONI)Il’IONS -_ Kl~b111EK

35 12 3

History of trauma Very marked abrasion Habitual abnormal movements

TABI,E

V.

INCIDENCE

OF TF,~CP~ROMANDIB~‘T.AK. OCCIAJSION AND WITH

AICTHRALGIA TRAEMATIC

IN ~XI)I~II)I~AL~S HISTORY XITMBER

No subjective or objectivfiw Occasional pain Frequent pain Objective temporomandibular Total

temDoromandibular

[‘Eli

9 4 signs onI> dvscrasia

CRNT

i.9 I .(i 0.5

\VI~I

NORMAI,

I’ER

CENT

30.0 13.3

10

33.3

i ;co 21

.- 23.3 100.0 iO.0

-_--

COLLiXTIVE

________-

-__

_____-

So subjective or objective Ocwsional pain Frequent pain Objective tempor0mandibular -

Total

-__-

temporo~nandibular

___--

--

----

findings signs

onl>

dyscrasiu _____--.--_~-

____--

-______

No subjective or objectix-e findings Occasional pain Frequent pain Ohjrctive temporomandihul:tr signs only Total

131:1

REVIEW

teml~oromantlibular

drwrasi:l

___--

SI~Zll~lbK

.i 1 ?I 0 !I 4

I’EK

(‘,iX’,’

.._ .,.,.ti 11.1 x1.:1 -.-(Ill.0 Ilrl~.~r 44.4

---___--. .--I’m PIGS’,‘__--. SI~nIBEI: ---___ <, 41.; .I 16.7 ; X.3 4 -..-xi.3 It’ lOI). 58.3 7

Fig. I.-A and B, The b-dw (II‘ thr: head, of the eminence varies from 25 tu 50”. Not? varies from 18 to 31 mm.

looking ~mo”c

into the fossa. in the eminencr.

The angle Length

of obliquity of eminence

COLLECTIVE

131;

REVIEW

Both t,he eminence and the anterior wall of the fossa are cover-cd by a Ia!-ct. of fibrocartilage. This layer of cartilage extends for a variable distanct bcymd i he crest, of the eminence and in the depth of the fossa almost to its apes, which would indicate that the concept of the fossa as a socket is fallacious. and one should consider the anterior inclined plane as a gliding articulwr surt’acc.

Fig.

2.--A

and

B, The depth of the fossa varies merit and the angle of slope

and is dependent of the :~rticul:r!’

upon the onlinmce.

degree

of dcvelop-

The anterior wall of the fossa and eminence forms a curving inclined plane whose angle with the horizontal varies from 15’ to 75”. This inclination is vcr) inconsistent depending on the prominence of t,hc articnlar tubcrcle, which in three specimens was so poorly developed as to present only a small convcs ridge. Of the three underdeveloped articular tubercles. two were found on either side of one head while the third was found on t,he right, side of’ a head which presented a normal joint on the left side. These eminences were covered with the usual cartilaginous layer and could not be considered to have been morn down

A*gl

bbrironta

Emwcnce ahd Ad.e~io~ FossrWall With 18.

fossa seen

Fig. 3.-A and B, I’lxnigraph is deep and the sloge of the in Fig. 2.

of normal t~rril,ol’onlan~libul~~~ anterior w:~Il and the eminence

joint (mouth closed). is much greater than

The that

IWk SeeI

1

il11:l

1 dc-

The angle of forward inclinat,ion of the head varied from 70’ to 17” ; the average was 40.4O. The variations on each side of one mandible were within a range of 16” or less in 21 pairs of condyles. The greatest disparity between sides was 42O.

COLLECTIVE

REVIEW

13'1

Tiewed from the side, the condyle is convcs OIL its articular encl. which terminates abruptly in a sharp overhanging ledge anteriorly at its junc~1ion with the neck just above the attachment of 1he capsule ant1 the pit for insertion of the external pt,erygoid muscle (Fig. 6). In this nrrn arc two or thlw v;lsc’lllal foramina. It is set on t,he ramus obliquc~l~ Viewed from above, the condyle is elliptical. at an angle of about 15’ with a lrontal plane of the KII~L~S, its medial end being in a displaced posteriorly (dorsalward) (Fig. i) . This angle of obliquity frontal plane is considerably less than that, of the cmincnce and plays a, part, in allowing rotational motion as pointed out l)elO\v.

The transverse length of the condylar articular surface averaged 19.3 mm. The articular cartilage surface measurements ranged from 13 mm. to 24 mm. as contrasted to 18 mm. to 31 mm. for the transverse length of t,he arlicular tubercle. Of the 56 paired condyles measured. 23 pairs showed less than 2 mm. difference. Of these, 11 pairs were identical in transverse measurements, 5 The grcatcst variat.ion on either pairs varied more than 2 mm. transversely. side was 8 mm. Viewed from behind, the condyle is gently conv’cs, in many insta.ncrs being flat. In several specimens, there was a cent.ral ridge correspondmg to t,he groovr on the articular eminence (Fig. 8, A, B, C, and I)). The articular cartilage covers only the most convex portion of t,he condyh and does not extend posteriorly for any appreciable distance. Tt, was on the articular cartilage of the cond>;le that, most, of the degenerative changes con)parable to those seen in other joints of the l)ody were seen. Of the group 01 68 articulations examined from this standpoint , 22 or 32 per cc>nt.revcalcd evi dence of lipping, spur formation, or actual erosion of the articular cartilage

In one instance, the ca rtilngc ot’ 111~concl\;lc was worn swap down to canccllous bone, extending as irrr ohIiqne lint down to the ramus. In anothcr~ inconsisted of a medial w-earing a,~~ir~so that the cwndylar stance, the deformity (Fig. !1, A, 13, and C) surface sloped medially at a SO0 angle The osseous relationship of wndylc and fossa, as seen in most textbook diagrams and in dry articulated skeletons, appears to he fallacious. The condylc owupies little if any of the del)th of the rossa with the .jaw in the physical rest position. In the open-mouth posit,ion, Ihe caondyle voniw to lie at a point anterior and inferior to the fossa and opposite the crest of’ the eminence (Fig. 10, A and B).

Evidcncc of developmental variations of fossat: and cTI11c1y1es aIlalog?:oLk+ to t,hose seen in the hip and shoulder is clcarl>- tliscernil~lc in this joint. These variations are most frequent in tlic fossa depths and/or prominence of the arIIowevcr, since the motion oetitular eminence a8 pointed out previously. curring in t,his joint is vastly different from tllat of’ the hip and shonlclcr, analoThat a poorly gies from a funct,ional standpoint ~nnst 1~ c;trcI’u11~ interpreted. developed fossa and eminence might predispose lo sitl)litsation and dislocation as seen in the hip does not seem atq~liwl~lc in ;I gliding joint; how~cr, it, is apparent that the modified range of motion thus allo~ctl might result in symptoms clinically (Fig. 2).

oded iculdr

$&cc

Wig.

ll).pA position.

A.

The occurrence of bursac or their equivalent as sctn in the viciniQ- of othw joints of the b.ody was not demonstrable in this region.

III. Mechanism of Motion in the Joint.-& previously noted, the condyle inclines obliquely forward and reaches only somewhat into the fossa dept,h. Its anterosuperior portion (the cartilage-covered articular surface) in t,hc closcdmouth position normally comes to lie at a point posterior and superior to the ernincrwc wit,11 the thin portion of disc intervening. The greatest condylar excursion is a for~~~lrd-downmard gliding motion, thr oblique downward glide bein, v influenced by the incline of the art ictlla 1 cminencc Tiord*” stated that the mot,ion probably was all in a horizontall> forward direct,ion. However, roentgen evidence corroborates the fact that the cond\-lar excursion describes a for\~ard-do~~ll\Yar(~ route:“’ (Fig. 13, -4, K, and C’ I. &nple protrusion of the mandible, keepin, w the mouth closed, brings the vondvle appreciably forward and in closer approximation to the inclined surface of the eminence (Fig. 13, II). If now the mandible is moved to the open-mouth position. the articular edge of t,he condyle comes to lit: opposite (below) the vanvex tdgcl of t,lie eminence (Fig. 13, B). With attempts at increasing the opclling ( forceful opening), the condylc tip moves slight]>- forward (Fig. 13, C). I)uring the movements just described, the disc2 is kept normally snugly applied to the condyle. It is ma.intained in this posit ion by virt,ue of its attachmcwtj to t,he capsule anteriorly and b- virtue of the pull of the external pterygoid It1 il muscle which is the principal activator of the forward gliding motion. similar fashion this snug approximation of disc to contl~-le allows the return of the disc to its normal position in mandibular ~~OSUIY. Ot,hcr mechanisms cannot account for this return of’ the tlisc as the l’osterior capsule is ~~XtJYlllC~~ lax and inelast,ic. In an analrsis of the mouth-opening movement, it, can b,e seen to consist oi’ a forward glide, a downward glide, and a hinge or tilt motion of the rondyle iIrOUJld a transverse axis. The gliding motion occurs between disc and eminence, the disc taking anv friction or stress developed. As the open-mouth position is reached. t,he poste&or thick port,ion of the disc is brought, against the cminencc. The hinge motion is generally considered as ocrurrin g in the lower joint cavity, i.e., between condyle and inferior surface of’ disc. Tt is difficult to determine how much motion wtuallv occurs between disc+ and conclyle in the living normal. The close approximati& of disc and condyle plus thv simnltancous insert,ion of cxtcrnal pterygoid into disc and condyle t)J two heads would make separate, dissociated movements difficult, although such dissociated movement has been accepted as occurring normally.‘“~ S1 Tt appears that the hinge motion generally accepted as occurring het~w-ccn tliscs and condyle is almost, cntirrly a tilting motion of disc and condylc acting as a unit, the axis of t,his tilt being at the anterior edge of condyle and disc. Whatever hinge motion does occur between disc and condyle is very slight. Huch an cxc~ursion wonltl be allowed by t,he previousl>- described looso posterior disccapsule structure. Likewise, the compact, anterwr attachmentSs indicatcl this is probably the stationary or axis center of motion. This motion is carried on simult,aneously with the forward glide when the mouth is opened. The ratio of condyle excursion to mouth opcnin g is approximatrl\6:l ilS measured OJL the x-ray films ; i.e., a condyle excursion of S mm. results in alltcrior invisor opening of 48 mm., hut there is variation of this ratio at tliffrrentS points along the excursion. This concept that the “hinge” motion is really il. “tilt !’ might more easilr explain some cases of “clicking or snapping, ” and will he discussed in the clinical portion of this study. Rotation of the cond\-lc on a vertical a,xis is slight and not radiographically demonstrable. With chewing motions of the mandihlc, the forward glide of one

1330

8.

B.

G.

I:, J, *pen in tlThe cond

acti\ thn

,, “~

e preceding similarity

j, of

n.

F.

Fig. i4.--ii and 23, Mouth open. Habitually dislocating mandible. The eminence and fossa are well developed. The angle of inclination of the condyle may be a factor in the recurrent dislocations which reduce themselves when the mouth is closrxl. C and D, Habitually dislocating joint. The fossa and eminence are well formed. The angle of inclination of the condyle is well demonstrated.

COLLECTIVE

REVIEW

1333

condyle is accompanied by slight rotation of the other condyle on a vertical axis (Fig. 13, E and F). Recently some authors have presented the masticatory motion as a forward glide of the condyle of the grinding side and a posterior movement of the other condyle.z7 This could not be corroborated by us either on the cadaver sperimons or on s-ray studies made with attempts to deviate the mandible lat,erally or cause a lateral excursion of the menton. Detailed stud>- and measurements of x-rays revealed no evidence in t,he normal joint of any posterior movement of the cond,vle i b’ig. 13, E), the space measurement between anterior condylar surface

1336

QCAHTERLY

REVIEW

OF LITERATCRE

5. Depression of the Ma~rliblc (For mechanics in the joint. SW I II. ,II(hc*hanism of Motion in the Joint.> .- The external pterygoid c*ont,raction draws the disc and c:ondyle forwartl, approximating condylc and eminencr. Further external ptrrygoid cant rad.ion draws the condyle and disc down the inclined plane of the cminc~ncc reslllting in a partial forward t,ilt.ing of t-he condyle. As pointed out previously, thcrc> is an approximate 6 :1 ratio of measured movement between condyles and incisors. Thus a 5 mm. exrllrsion of condplc would result in a 30 mm. separation of incisor teeth. This ratio obviously will vary depending on ~ndylar cx(*urThUS sion and become increasingly greater as the ~ond,vlc moves anteriorly. the action of the external pterpgoid results in depressing the mandibln to a point of approximately a 35 mm. to 40 mm. incisal opening. Assuming the length of f he external pt,erygoid t.o he approximately one inch or more and since it is a hipcnnate muscle, one can expect, the exttirnal pterygoicl to lx> capable of contractin-g a,t least, one-half inch or 12.5 mm. (Sumrrous physiologists have attempted to establish a constant relat,ionship of muscle fihcr length to contraction rangcl- -the consenszP. 4z accepts approximately 50 pcbr cent of muscle fiber length as the normal contractility range.) This appears IO offer some proof that the external pterygoid mns~lc is capable ol’ drawing 1ho condyle forward at, least 12 mm.? which would a.ccount, for an incaisor separatiolj OIlC’ of ttleSC! t'ilCof approximately 70 mm. if other factors did not interfere. tars is t,he inefficiency of the lint of pull of the external pt,erygoid ill :~~~o~~l~llislling the tilting action of tlrr disc-condyle near the extreme of I he opening a~[, the insertion of t,he external pterygoid at this point being partially inferior to Two explanations may he given for further openthe main belly of the mnwlc. ing. One is the possible contraction of the. suprah~oid muscles causing a IV trusion of the menton and consequent tilt, of the disc-condylc. Thcb otller PSplanation is that of Lordl” that, the sphenomandibular and stylo~t~~~~~clibl~li~r lir-caments act to anchor the ramus so that any furthc,r contraction of I ho cstcrnal pterygoid u-ill accomplish a tilt of t,he condyle. It appears that the normal opening of the mout,h is accomplished by PXtornal ptefy+goid action and that. forced opening is aided by ihc snprahyoid muscle activity. It is possible that the normal mandible can be depressed to a.n ineisal opcning of 8 mm. by suprahyoid niuscle action alone.3” MainlandL” states that the hyoid bone is not fixed during normal mandibular opening, and thus the SllJ)t’ilhyoid muscles appear to havn no direct role in producing normal depression of the mandible. In our own series of t,wcnt,y young adult normal males, an avcl*agc opening stress of 15 pounds was ob,tained HI. t,he menton area at an average in&al o~xmcould move their tongues readily during iIn> ing of 28 mm. All individuals phase of the opening movement and could carry out, swallowing movements \vitl-1 the mouth open under stress. Thompson and Brodie3”s 30 pointed out that in normal mandibular opening and closing the position of the hyoid bone is not ma,rkedly altered, but that iti bilateral condylectomy, where the external pterygoid insertion has been tlest.royed, t,he hyoid bone is markedly depressed with mandibular opening. 0111 own attempts at, stimulating the suprahyoid group with three milliamperes ot galvanic current produced muscle contraction, hut did not produce mandibular Seven-milliampere stimulation of both infra- and suprahyoid depression. groups also fa,iled to produce mandibular depression. During the depression of the mandible the antagonistic isotonic cont.raction of the temporalis, masse&, and internal pterygoid muscles serves t,he purpose of smooth condylar action without any appreciable stress being developed in the joint.

COLLECTIVE

REVIEW

1337

V. Histologic Component&--Twenty-four articular discs from cadavers were examined histologically. The specimens were obtained from a variable age group. They were not examined with reference to age, sex, or disease, but as an over-all review in an attempt to determine, if possible, the normal histologic appearance of the disc. All were cut longitudinally, sect,ioned at five microns, and st,ained with standard hematoxylin-eosin technique. Additional sections of the disc with surrounding tissue, including the temporomandih,~~lar joint (Fig. 11) were made. The histologic appearance corresponds very closeI> with t,hat described by Robinson.’ The discs of all specimens appear avascular except at the lateral borders. This is not entirely constant but appears to be associated with the amount of denseness of the collagenous tissue of the body of the disc. In the disc (Fig. II), vascltlarity is noted particularly at both the anterior and posterior portions of the disc. 1. Ny7zocicr1,Membrane.-The “ synovial membrane *‘40,41 is not synovia in the true sense. In most areas the “membrane” lining the synovial space and caovcring the surface of the disc above the condyle does not appear to be a continuous covering but covers it only in its outer one-third, the central portion of the disc not showing a membrane. The synovial layer, where seen, is made up of two or three rows of elongated cells with long, flat, deeply-staining nuclei. Occasionally, a small blood vessel is seen, but blood vessels appear to be mostly at. the lateral borders of the disc. The synovial layer in most areas blends with the underlying fibrous tissue at the lateral borders of the disc and appears to become much thinner toward the central part of the disc in which part it cannot, bc seen; but in these areas there appears to be a tendency for the fibrous tissue to be more cellular with Aatt,ened, elongated nuclei which are lined up on the surface with the long axis of the nuclei parallel to the longitudinal axis of the disc. ds one approaches the lateral borders of the disc, the synovial surface is less compact, the nuclei are more rounded, and in areas there is a tendency ol the synovial layer to form low-lying folds. 2. Horde of the Disc.-Beneath the synovial layer and continuing in the areas after it has faded out, a dense connective tissue is seen. This dense connective tissue is made up of compact parallel dense collagenous bundles. (h:casional fibroblasts are seen. In some of the sections examined, fibroblast,s are rare. Occasionally, there are areas in which the body of the disc is made up of less dense fibrous tissue. At times, these collagenous bundles assume a whorlThese areas are toward the lateral like appearance su ggesting sponginess. borders of the disc. 3. J’nscuZu,ritJj.-As noted previously, vascularit,y is present about i-he lateral borders of the disc. *4n occasional small vessel can be made out in the synovial layer. The central portion of the disc is avascular. Xo cartilage is evident, in any of the sections examined. (To he conch&d

in the Quarferly

References

Review Section of the January, 1950, isnuc. will appear at the end of the rrziew.)