TJlE DENTA L COSMOS.

CLASSIFICATION OF MALOCCLUSION.· IIY BDW" RD H. ""GU, D. D.S., ST. LOUIS, MO.

TJiE tenn "irregularities of the teeth," as it is usually applied 10 express teeth that are twisted or unevenly arranged, does not, in the aut.h?r's opinion, properly express the full meaning of these deformItIes. It wonld seem that the term malocclusion would be far more e.l<pressive; for in studying the subject we must not lose sight of the importance of the dental apparatus as a whole and the important relations 1I0t only of the two arches to each other, but of the individual teeth to one another. The shapes of the cusps. crowns, roots, and the very structnre are all designed for the pur­pose of making occlusion the one grand object, in order that they may best serve the purpose for which they were designed,~namely, the cutting and grinding of -the food. Examined carefnlly, it will be seen that there can be no "irregularities" of the teeth if they are in perfect occlnsion, bnt that all mllst be regular and even, each contributing to the snppo" of the others, and all in perfect har­mony. Not only Ims, but the jaws, the muscles of mastication, the lips, and even the facial lines, probably, wil! be in best hamlOny with the peculiar facial type oJ the individual.

There!ore, it would seem that the term malocclusion of any tooth or nnmber of teeth would not only better express the true condition, but naturally and constantly suggest the paramount importance of occlusion in the study and treatment of these deformities, instead of making it secondary or even losing sight of it entirely, as has been too mm::h the caliC in the past. The author has become firmly convinced that occlusion is the very basis of the science, and that in the treatment of cases, unless occlusion is established, the resu lts will be largely of the nature of failures. So in the pages that are to follow we shall make occlusion the central thought, and on it base the classification of "irregularities" as well as the nomenclature; and will define orthodontia as being that science which has for itll object the correction of malocclusion of the teeth.

DIAGNOSIS O F C"sr..5. In every case of malocclusion of the teeth presented for treat­

mentthe importance of a correct diagnosis of the true conditions, and the requirements, cannot be overestimated. Otherwise any plan of treatment will be very uncertain as to results; III fact, most apt to lead to failure !With all of its embarrassments.

From an extensive intercourse with dentists and students I am impressed with the belief that although diagnosis is the question of great~t importance, it is yet apparently the least intelligently studied and comprehended.

In the beginning, I wish to thorooghly impress the necessity for complete -separation of diaglWsU from trealmenf. This statement seems necessary for the reason that I have 50 frequently noted a mental conAict in the endeavor to consider the two t ogether in the

· From B forthcomin~ book by tbe author.

,

fin, ''''!<I IKe, tht quution 01 treatment by applianttl or by ntne­bOn apparently forcing iUdI into the ftn, ....... bflorc tk £a.:t. upon which (10_ lhould be b7 5 ' d nau had d"" ~idcratioo. M a matter ol lacl, if tile diagnosia 0/ any (ivm CJK is Ant thoroughty mailcm:! tbe line of IrcaU"."1 and the applianca n«up')' 10 bring .boot tbe yariom looch-movcmcnta required Ire, in ncul, every instance, dearly indiea,cd, ncn to the duic .. nee"",,,,), lor retlining the I~th when correctly placed.

In order to diaanooc all """"" of m~locciuslOn corretti), it ;. ncc_ty to be familiar with. fint, the normal or id..,l occlusion of the Imh; ICCOfId, the IlQf'mal faciall'n ... That must be to fixed in the mind .. \0 form the buis from which to fUton, and tQ intt!­li$"cntJy note all d""ialions from the normal; and i, mUI' follow lhat WIthout dear, fiud, and definite idea5 U 10 the normal, the limill Or boundary lin .. .:>( 110. abncmnal muO! . 1$0 be vague Ind indefi­nite, and Ih~ line of Ir.atmmtthe morest empir;c;.m.

A knowledge of tbe occlusion of tbe teeth being of the finl importance, Moul d mlbrilN a kno ... led~ 01 1'0' only th. normal relation, oI lhe occltuOll ourbcea of bulh permanent tnd dtcidtKIUS 1-". bul of lheir mt"'c forms and , lructurQ. The growtfl aDd nonnaI Mwlopmenl of the Ja ... and mUlde •. tQgelhu with th. deyelop_nl oIth. tedh and the nonnaI periods for tskin&, tbrir positioM in Ihe "!'Chcs. ohould .... ciw: caulul attenl;o". Our per_ ... ptiona 01 me .ubi..::t ...... 101 be broadened abo by • comparatiye S{udy ollhe occlu,;o" of the I""h of tb low" animll •.

NO"WAL OCCLIISIO ...

Thi. knowledge i, th. baai, of the ~.n<:e and Ihe mo5I impor_ tMtt leaon to Ihe .Jtudcnt of orthodontia. The limits 01 tbit work will. hoWC>'er, perrtlit 01 the comidoratloo 01 only the ITIOItlmpor_ tant 01 it. mlny !lha.... ' "I referTing 10 F,l&," I and 2, wmch rep",sent thc teelh in the ideo. ocdu.ion, it .. i!! be .. en that each dentl l a!'Ch deocribco a &,racelul cu rve, and that the teeth in tI~ .. arch", are w.",," ng-ed as 10) be in the gTUt...t ha11llO<l)' wilh their Idlows In th e III!"" ....::b, as ... 11 .. with 111_ in ebe <>ppOSitc.

TI>eiower .rch it ...., .. ~h.:It smaller tlun the uPlltr. 10 that in oceIu.ion Ih. labi&! and huceal surf.occt of the leelh of the UP!"'" ia ... slighdy ovuhtng Iha.c of the low... Th. key to) o<cluMO)n is Ihe rclati .... pooil~ of lhe ~,..t moIa.... In n.orma.l o<cll .. ;o" Ihe mcslo-buoc:al ~u',P 01 the upper firs! molar i. rccoeiwed in Ih •• ukus betWttl! lhe IIICSla1 and distal buccalrosps of Ihe lowu,lhe Ili!(h! .. yerhanrina: ~ the upper tNth bringin!( tht buccal ClU.s- 01 Ih. hituspOd. and mol ... 01 the lower jaw into tho me.io-d15ta! IlI!ci of th.i •• otag""ill" .... hil. the upper centr;ll., !at .... l., and cuspid. oYorlap tho lowe. about one-thi rd the length olth"; r e", .. ns. Th. Upp'" (.mral being broad .. than the 10_'. "«:ouarily exlends beyond it di stally. oYcrlapping. in addition, about ""c· hall of the lower lateral; the upper lateral occlude. ,,;Ih the remai ning portion 0/ Ihio tOOlh, and wilh the mc.i.l indine 01 the lo we. cu.pid. the ",~ial incline 01 Ih. upprr cuspid ocoluding .. ith the din,1 incline

YOl.. XL1 ._1S

'50 THE DENTAl. COS/liOS.

of the lower; the dista.l incline of the upper cuspid occludes with the mesial incl ine of the buccal cusp of the lower first bicuspid; the mesial incline of the buccal cusp of the upper first bicuspid oedudes with the distal incnne of the buccal cusp of the lower first bicuspid.

FIG. I .

FIG. 2.

This order is continued through the bicuspids. The mesial and distal inclines 01 the mesio-buccal cusp of the upper first molar a~ received between t he mesial and distal buccal cusps 01 the lower first molar, and the indinoes of the disto-buccal cusp are received

,.I.lfGLB..--CLASSIFIC\TlON O.f MALOCCLUS ION. 251

between the dis to-buccal cusp of the first lower and the mesio­buccal cusp 01 the second lower. This same order is continued with the second and third molars, the distal incline of the disto­buccal cusp of the upper third molar having no occlusion. It will thus be seen that each of the teeth in both jaws has two antagonists or suppons in the opp06i1e jaw, except the lower centrals and the upper thi rd molar!!.

As the inclined planes match and harmonize most perfectly in the bucco-occlusal relations of the leeth, so there is a Similar arrange­ment in the lingua-occlusal relations, except that the lower bi­cuspids and molars project beyond the upper into the oral space; likewise in the transv~ arrangement, the buccal cusps of the lower molars and bicuspids pass between the butea] and lingual cusps of the upper molars and bicuspids, and the lingual cusps of the upper moJars and bkuspids ~tw~n the buccal and lingual cusps of the lower molars and bicuspids. The grinding surfaces are thus enoml0usly increased in extell't and effiCiency o.ver what would be possible if they consisted of a single row of cusps or of plane surfaces. But increase of masticating surface is not the only, perhaps not the most important, reason for this complex interdigi­tation of the cusps and inclined planes of the t~th. A very impor­tant office of the in terdigita ting cusps and planes is the part they play in the mutual support 01 the teeth. The sius, forms, interdigi­tating surfaces. and positions of the teeth in the arches are sneh as to give to one another, singly and collectively, the greatest possible support in an directions.

Another important part played by the inclined p1anes of the cusps is in influencin~ the directions of the teeth while erupting and taking their positlons in the arches. If, however, their influ­en.::e is perverted, they may be<:ome mischievous factors in the pro­duction of malocclusion. When the teeth first emerge from the gunu conskierable displacement is often noticeable, but this need occasion no uneasinCl;S, provided, as eruption progresses, their cusps pass into the normal influence of the incli~d planes of the opposing cusps; but once passed beyond the normal influence into the abnormal they will not only be deflected from their proper relations in the arch, but win assist in the displacement of the ?PPOsin~ teeth, as well, oftentimes, as of those which are to follow lD n'tiptlon.

So the dividing line between harmony and inharmony of occlu­sion is often very slight. Hence the importance of careful atten­tion during the important period covering the eruption of the permanent -teeth.

THE FORCES WHICH CONTROL OCCLUSION,

Harmony between the upper and lower arches and their teeth is also powerfully promoted by their normal action and reaction upon each other. As the teeth of the lower arch empt before those or the upper, and are consequently to an extent fixed in their pO$i­tions belore their antagonists appear, it follows that the lower arch is the form over which the upper is molded. In other words, the

'5' THE DENTAL COSNOS.

lower arch exerts a cOlltfolHng influence over the form of the upper and the positions of the teeth therein. O f course, the upper reach; upon the lower, but it is unquestionable, in the author's opinion, that the lower arch is the mOTC important factor, not the upper, as has hitherto been taught.

It will thus be readily seen how greatly one arch contributes to the other in maintaining ils fann and size so that pressure, as, for example, on the labial surfaces of the upper inCIsors, would be resisted not only by all the upper teeth acting as keystones in an arch of masonry, but also by the teeth of the lower arch acting through occlusion.

Inversely, then, one arch canllot be altered in shape without modifying that 01 the other, nor can it be altered in size without soon e.xercising a marked effect upon Ihe other.

This important fact is of the greatest inlerest 10 us as students of orthodontia,-namely, that in a caose of perfect occlusion, as in the illustrative case shown, each tooth is not only in perfect harmony with (,"ery Olher, but helps to maintain il in its harmonious rela­tions; for lhe cusps interlock "nd rod. sloping plane servcs to IU)t only kttp the tooth in positWn, to prevent" from sliding out, tnu tl1 wedge" into position if slighily moIpo.mi; that is, if not beyond the normal influence ollhe indined plane.

A careful study of the relations of the indined planes and the marginal, triangular. transverse, and oblique ridges, in connection with the movements of .the jaw, cannot fail to impress thoughtful persons with the wonderful efficiency 01 the human teeth for incis­mg and triturating the food required by man, and with the marvel­OUJ arrangement for self-cleansing and consequent self-preserva­tiou wJ(icl! they display.

The harmonioll'S relations of the ocelusal planes and of the den­tal arches are further as-sisted by another lorce,-namely, muscular ptenure, the tong~ acting upon the inside and the lips and cheeks upon the outside of the arches. The latter serve to keep the arches from spreading, as do the hoops upon the staves 01 a cask; the fanner prevents too great encroachment upon the oral space. I am satisfied that tftis muscular pressure is a far more important factor in relation to the study and correction of malocclusion than is genemlly recognized. I t not only contributes to maintaining the teeth in their 'IlOrmal positions and to harmony in the size of the normal arche!l, but it is eqnally powerful in maintaining in­harmony rin the sizes or rekltions 01 the arches and malocdusion of the teeth, when ooce established.

So it will be seeu that the occlusion of the teeth is maintained, first, by the occlusal inclined planl'$ o f the cusps; second. by the support given by the interdependence of the arches due to their harmony in sizes when in normal relations; third, by the influence of the mu!c1es labially, buccally. and Iingual1y.

The illll'Strations show the result where these forces have acted normally,-a hannoniously aligned and occluded denture.

It should be borne in mind that these influeoces are none the I~s powerful in cases 01 malocclusion.

ANGLF.,-CLASSIFlCATJON OF MALOCCLUSION. 253

I t is interesting and instructive to note the resul t of ,these forces even in the earliest indications 01 malocclusion.

Fig. 3 iIlustl"Qtes a developing form of malocclusion very com­mon, and famil iar to all observing dentists. The case is that of a child where the four lower permanent indsors are fully erupted, but one of them (the left lateral) has been deflected linguallJ (Figs. 3 and 4), the arches being thus deprived of the wedgtng and retain ing influence of this tooth. The external pressure of the lips has closed the space and diminished the size 01 the arc.h.

FIG. J.

F IG. 4.

At the same time pressure of the lips and cheeks (aided by the occlusal planes) is gradually molding the upper arch to conform to the abnormal size of me lO'Wer.

It will thus be seen how effectually the maintenance of the mal­occlusion has been provided lor, and how hopeless it is to expect nature to correct these deformities unaided. As well might we expect the tell-cure of strabismus of the eye or curvature of the 'PIne. How absurd, even pernicious, then, is the common advice of many dentists to parents to '1et natu re alone and the teeth will straighten thellUleIves."

'54 THE DENTAL COSIoIOS.

Recognizing the potency of these influences, it must be apparent to every thoughtful observer that eases of this kind, instead 01 being self-corrective, will become more and morc complicated as time goes on and each succeeding permanent tooth is erupted. In all such cases the positions of the incoming permanent incisors should be guarded with jealous care, and be maintained by corn~c· rive procedure if necessary. when, unless there be unusual influ­ences or tendencies toward malocclusion, the positions of the teeth in the upper arch will be directed normally. (Fig. 5.)

On the other hand, for the reason previously stated, if the teeth of the lower arch are per~itted to remain in malposition, even to the slightest overlapping of one or more of the incisors or cuspids, the normal size of the arch will be diminished to that extent, with a torr~sponding contract jon of the size of the upper arch by some form of bunching as a result of the inftu~nce of the lips,

FIG. s.

~N . ...

The absurdity, then, of correcting the malpositions of the teeth of the upper arch alone, without equal attention to those of the lower, as is so often done, becomes apparent. These same influ· ences may ·be traced in a similar manner in any of tll<!. cases herein· aher illustrated.

LINE OF OCCLUSION.

When the teeth are in normal occlusion the line of greatest occlusal contact will be found to pass over the ~sial and distal inclined planes of ~he buccal cusps of the molars and bicuspids and the cutting-edges of the c\lIjpids and incisors of the lower arch, and along the sulcus between the buccal and lingual cusps of the upper molars and bicuspids, thence forward, crossing the lingual ridge of the cuspids and the marginal ridges of the incisors at a point about one-third the length of thei r crowns from their cmting.edges. This we shall call the Hne of occlusion.

This line describes more or less of a parabolic curve, and varies somewhat within the limits of the normal, according to the race, type, temperament, etc., of the individual, and must be determined in any given cas.;. of malocclusion by the judgment of the operator

ANGLE.-CU,SSIFlCATION OF MALOCCLUSION. 255

after a careful study of the featu res, facial lines, forms of teeth as related to temperament, e~.

In the diagnosis of cases it is important that we should have this definite line as a more accurate base from which to reason than the ooarser outline, as indicated by the incisive and occlusal ends of the teeth.

NOMENCLATURE OF MALOCCLUSION.

All teeth found out of harmony with the line of occlusion may be said to occupy pooitions of malocclusion, and eacb tooth may occupy any of seven malpositions or their various deviatioJl'!l and combinations.

A definiU nomenclature is as necessary in orthodontia as in anatomy. The indefinite outlines and mere phrases heretofore used are totally inadequate. The terms for describing the various mal­occlusions should be so precise as to convey at once a clear idea of the nature of the malpooition to be corrected. T he author there­fore suggests the following, which, while perhaps not perfect, still seems to be a great improvement over present usage, . For example, a tooth outside of t he line of occlusion may be said

10 be in buccal or labial occlusion; when inside this line, in lingual occlusion; or, if farmer forward mesially than no~aJ, in mesial occlusion; if in the opposite direction, in distat occlusIon; if tumed on its axis i-t is in torso occlusion. Teeth not sufficiently elevated in thei r sockets would be in iufI'Q-occiusion, and those that occupy positions of too great elevation would be in supra-OCclusion.

These different malpositions, in their modificatioos and combina­tions, form the basis for limitless variations of occlusion from the normal, from the simplest to the most complex, in which may be involved not ooly the malpositions of all the teeth, bnt even the relations of the jaws, resultiug in marked deformities and produc­ing appearances even repulsive.

CLASSIFICATION OP MALOCCLUSION.

As al ready stated, there can be but seven distinct positions which teeth in malocdusiou can occupy. These, with their inclinations, form combinations practically limitless in variety, to the casual observer presenting differences so distinctive as to render each apparently wholly dissimilar from all the others. Failure to grasp the underlying principles has given rise to t he teachiug that, as each case is SQ radically different from all others, it necessitates the invention and construction of an appliance to meet its special requirements.

In reali ty all cases of in well-defined classes as by thoroughly occlusion and of of any given Cllse

At the same time, il with the possibilities of tooth-move-ment and with t he changes requisite to each distinct and sepa1'1l.te

,,6 THE DENTAL COSMOS.

ciass, to attain harmony in occlusion and in the facial lines, and -a knowledge of the standard appliances designed for each special

Flc. 6.

FIC . 7.

class as best suited 10 produce these changes, will reduce the diffi­culties 01 treatment to the minimum.

A"'GLE.-CU.5SIf'I~TION O f /IIALOCCLUS ION. 257

In diagnosing cases of malocclusion we mUSI consider, first, the mesio-distal relations of the dental arches; second, the individual positions of the teeth. In what is said upon diagnosis and in the

FIG, 8,

Fu:" \).

classification which follows, for convenience, two points have been selected from which 10 nOle varialions from the normal in the ar<;hes. These points are indicated by dark lines in the engrav-

THE DENTAL COSMOS.

ings, which show the normal relations of the cuspids and mesio­buccal cusp 01 the upper first molar with the buccal groove of the lower first molar.

Of course, in determining the mesio-distal variations oJl of the teeth are to be taken into consideration, but the points indicated have long been favorites with the author in beginning the diagno­sis of cases, for the reason that the first molars and cuspids are far more reliable as points from which to judge, owing to t he fact that they are found 10 occupy normal posillons far more often than any

FlO. 10.

of the other leeth, the molars being less restrained in taking tbeir positions, while the cuspids. owing to their history and great size. force their way usually in to relatively normal positions in tbeir arches.

ems I. Fig. 6. Relative position of the dental arches, mesio­distally, normal, with first molars usually in normal occlusion, although one or more may be in linguoJ or buccol occlusion. Cases belonging 10 th is class far exceed in number those of all other classes combined (see table), ranging from the simple overlapping of a single incisor to the most complex. involving the positions of all of the teeth of both arches. (Fig. 7.)

The avera·ge case, Fig. 6, is where the malocclusion is princi­pally confined to the incisors of both upper and lower arches.

AN(;L£.--<:LASSIFI (:ATlON 0 " YALOCCLUSI OI'I'. 259

F Ul. II .

Fl O. n .

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THE D£NTAL 00$11105.

Clou II. Relative muio.-distal relations of the dental archer; abnormal; all the lower teeth ocd udlnl;t distal to nonnal, producing very marked inhannony in the inciSiVe region and in the facial lines.

Of this class there are two divisions, each having a subdivision. The first division is characterized by a narrowing of the upper arch, lengthened and protruding upper incisors, accompanied by abnormal function of the HPi and some fonn of nual obstroction and mouth.breathing. (Figs. 8 and~)

F,e. [J .

The general characteristics of the fitst .ubdivision are the same a.a in the first division (Fig. 8), only of a leu degTee, in that one of the lateral halves only is in distal occlusion, the relat ion of the other lateral half being normal, all as shO'll'n in Fig . 10- Patient alSOt mouth-breather.

The second division (Fif. II) is characterized by lesa narrowing of the upper arch, lingwd mdination of the upper incisors, and by more or less bunching of the same, as in Fig. II ; and is associated woilh nonnal nasal and lip function (Fig. 12).

The peculiarities of tma subdivision are similar to those 01 Division 2, Qus II, jutt ducribed, e)t~pt that one of the lateral hIIolves only is in distal occlusion, the other lateral half being nor­mal, as in Fig, 13-

Closs 111. _The rdalion of the jaws i. abnonnal, all the lower

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ANGLE.-<:U.SSlfICA1:ION Of MALOCCLUSI ON. Ol6r

teeth occluding mesial to normal the width of one bicuspid. (Fig. r4), or even more in extreme cases (Fig. IS). The arrange­ment 01 the teeth in the arches varies greatly in this class,

F,G. 14.

F,G. IS.

FIG .• 6.

from that 01 quite even alignment to cOllsiderable bunching and overlapping, espedally in the upper areh (Fig. 16). T here is usually a lingual indination of the lower incisors and cuspids,

THE OENT-'L COSMOS.

whiclt becomes more pronounc:ed as the patient grows older, due to the pressure of the lower lip in the effort to clO!;e the mouth.

The inharmony in the sile 01 the arches is usually due to the inharmonious development 01 the maxillary bones, the angle of the lower jaw being more obtuse than normal; or it may be the result of over-development in the body oi the jaw. Oc:casionally c:ases

FIG. 17.

FIG. 18.

are met with where there seems to be over-development in c:ertain localities of the body, as in Fig. '7. Another model in the author's colle<:tion shows local over-development of both the lateral halves between the bic:uspids, one spac:e being greater than the width of one bicuspid, tlte other not quile so great.

In olher cases met with the jaw seems to be normal in form, t he

,

ANGLE .-CLASSIF lCATION OF MALOCCLUSION. 263

protrusion apparently being caused by the temporo-maxillary articulation being farther anterior than normal, this probably being due to the gradual sliding forward of the condyles and to modi fica­tions of the foss~.

In all cases of malocclusion belonging to this <:lass the marring of the facial lines is most noticeable. amounling in some instances to most pronounced deformities (Fig. 18).

rIG. 19-

This <:lass also has one subdivision, the general characteristics of which are the same as those of the main <:lass, except that the inharmony is less in degree, in that one of the lateral halves only is in mesial occlusion, the other lateral half being normal, as in Fig. 19-

It is quite probable that all cases met with will be found to be embraced in the above classification. There st i11 remains, how­ever, one possible class,-viz, where one of the lateral halves is in mesial occlusion while the other is in distal, but cases having these

•

•

350 THi:: Vi::~T'\L CUSMOS.

CLASS IFICATION OF MALOCCLUSION.* B\' ~DW.'RD II .. ',,"GL~. D.D.S., "T. U)UIS. >to .

ISFI,n; ,\"C i:: UI' Tlill LIPS, C UllEKS, .,SI> Occu ; s.'l. PJ..\SES (I':

}'LII.oCCI.uslOx uF THE TEETI!.

Ix the chapter on diagnosis of cases we ha l'e uoted the powerful influence in normal occlusion of the muscles, the lips, and tht checks, and of the inclinations of the occlusal plall{'S of the teeth in establhhing aud maill1.ailliug hanllolly in rciation of the teeth and also of the relative sizes of the arches. In cases of malocclusion belonging to Class I th~ arches are usually mon: or less contracted, and as a result we find the teeth cTOwded, bunched, and overlap­ping. or, as cnlddy designated by one author, ·'jumbled."' In these cases thc lips sen'c as a constatH amI powerfnl factor in main­taining this condition, usually acting with equal effect upon both an:hes, and effe('\ually combating any influence 01 the tongut or any inhtrent tendency on the patt of nature toward self-correction. In other words, the narrow and diminished sizes of the arches are fixed. and they are I)revented Irom enlarging by the lips with a force equal in power \0 that exerted ",h..,n the arches are of normal siu and the teeth in nonnal occlusion. Likewise, each inclined plane of the cusps out of harmony in the occlusion serves to main­tain it in its malposition. or to wedge it stilliarther out of position upon each closure 01 the jaw. These 5ame inflnencc5 are also easily traceable throughout all the other classes 01 malocclusion.

FACI .I I- AltT-NOIU1 ,1I. FACt.l!. LIXES.

One of the evil effects of malocclusion is the marring or distor­tion of the normal facial lines. I t follows that, in the application 01 the principles 01 orthodontia. 01lT effons should he w directed that the improvement 01 these lines of inhannony shall rt'~nlt in molJ ing and modifying them to harmonize with the ideal lines of ladal beauty so far as lies within the range of the possibi lities of the art and of the type and temperament of the individual. Our opportunities for benefiting humanity are very great in this field, far exceeding those offered hy any other hranch of den tal science: lor patients with facial lines so distorte.1 as sometimes to be a marked .ldormity and a sonrce of constant humiliation to tht'm­selves and their friends may he so treated as to hring ahom a com­plete transformation 01 tht: lacial expression. even to the estahlish­ment 01 lines of heanty. Rill. lacking a I)TOper al)prcriation of the true purpose of orthodontia. we ma~' work in sitch utter ignorance of the requirements of lacial art. as is often {lone. as 10 110t onll' fail to improve th{' appearance, hm even to prodnce r~lllts $til1 more unplea5ing than the original condition.

Tn order to work intelligently it is important that we shall have first fixed in our minds the outlines of the I)erleel face. so that we may ever have au ideal which, like teeth in normal occlusion. shall

'Copy,;ght. ,80;19. by E,lwarrl H. Angle.

A{I:<';LE.- Cl ... I SSIYlC,ITIOX OF .\l. ILOCCLUSION. 351

serve as a paltern Irom which to note del'iations and to guide us in our effort. toward the establishment 01 the normal.

For this perfect lace we .hall look in vain among the people we meet. Although we may lind many having more or less 01 the characteristics 01 beauty, all will be lound to posses. one or more lines not in harmon), with the ideal lace.

Raphael. the great artist, said. "There is nothing so rare as pcor­Irct beauty in woman." When painting the head of Galatea he was uuable to find in the faces of the living a sufficiently perfect type 01 beauty 10 he his model. anll was compelled to substitute lor nature a certain ;,lenl illl'p;red hy his laney.

f"w •. 20.

In proceeding to define ueallly. all that the writers on art have been able to do is to affirm the expression 01 Albrecht Durer. that "beanty is the reverse 01 defonnity. 111e marc remote from deformity. thc nearer the approoch to beauty."

We must have recourse. then. to the pnrely ideal.-to suggest, to gtlide. to vary in imitatio l] , but never 10 rigidly copy. "A profi le well chosen, all the lealmes will be made 10 harmonize with 'it; and according to the profile will correspond 11] form the beauty of all the othu features. No fa c~' was ever repulsive whete the profile was beantilul. and 1]0 fac~ {"an be made beautilul while the profile is ugly."

Fig. 20 represents the I)tofi le 01 a face 50 perfect in outline that

35' THE DEto;TA L COSMOS.

it has long been the model lOT .tudents of facial art. It is thai of Apollo, one of the Grecian mythological gods. Jt is supposed to be so faultless in IOTrlI thatta challge it in the least would be to mar the wonderful harmony 01 proportions; as Fuseli puts ii, "Shorten the lIose by but the tenth 01 an inch and Ihe god would be destroyed."

All the essentials of beauty found in this face can be traced with but minu te variations in all other masterpieces 01 art representing ideal facial beauty, as the Psyche. Sistine Madonn~ . 1\1edusa, Venus de Milo, etc., and consisl in a short, finely curved. and prominent

FIG. 21,'

upper lip ; a fuil, round, but less prominent lower lip, and a strongly marked depression at the base 01 the lower lip, giviog roundness and character to the chin. These characteristics of the [ower part o f the face are elements of beauty wherever found. AI the present day the pure Greek type is rar ely seen, but we ne~rtheles.s do see in all handsome profiles very much the same outline in the lower part of the face that has been indicated. the variations being in the upper half of the face and not in the lower.

In studying the perfection of the profile it win be seen that it is in perfect harmony with a st raijtht line at three points.-namely.

·Morri.on. photogr~pher. Copyrighted.

Al>" (;U':.---CLASS" " C.ITION Of ~ALOCCLUSION. 353

the most prominent poin ts of the frontal and ment"l eminell<:es, and the middle of the ala of the nose.

As a convenience we shall call this the line of harmony. It wi!! be found of great value a$ a basis of diagno.sis, serving the Silme purpose in the esthctiCJ of the lace as does the line 01 occlusion In indicating the variations of the teeth from the normal alignment.

Fig. 21 sho .... s Ihe application 01 this line to another face 01 much beauty, which, it will he 5ecn, is in harmony at the three points above indicated.

Fig. 22 sh~'s still another very beautilul lace, in which it is cuy 10 note ha ll' nearly the line of ha rmony approaches the ideal:

F ir.. 22 ·

whi le Fig. 23 shows another face in many respecls quite perfect, but when measured by the line of harmony we may quickly deteet its variations from the ideal and the conseqllellt unpleasing effect.

Fig. 24 shows the profil e of Jli!! another fa ce in which the varia· tion from Ihe line of harmonv is "ery grnl, and the result a real deformity. •

Dr. McDowell once suggested to me that we might possibly use this line to describe certain local \'ariations from the normal. I think the suggestion is a good one. and will offer the following plan. As we readily find that al1~' variat ion in any region of the

·"orr;..:m. photog,"ph(r. Cop)· r;gh!( d.

3,. TH Il: IJ ES T.\ L ("OS)IOS.

I,ron!.: may be ~asit.\· d"It'Cled I1 pOI1 "IlPlir.u ion of th is line, we wi ll :lJl[Jly the te rms pTO- or sub-. according to th.',·c1opmenr and

F", . 2J.

IOUlion, to uesignaU Ih('sc va riations. as, lor example, suJ.>..inler­maxillary , denOling a n arrested development in Ihe region of the

"KGLE.-CU.~SJ~Jc.\TJO;>; UF ll.\J.UCCJ.USJOX. 355

illtennaxil!ary bones : o r pro-intermaxillary, to describe the oppa­~itc, or cxcessi"e development; pro-inferior maxillary and sub-

c,' ,_ ,. .. ,-

1I1ferior maxillary. to designate excessive or deticient development , or retrusion or protnlsion of the same: or pro-fllental and sub-

TilE DE),;TAL COSldOS.

mental development, to denote excess or deficiency in the develop­ment 01 the chin; or pro- and sub-denial, to denote the excessive inclination outward or inward 01 the incisors. etc. In like manller prominence or deficiency in the development of the lips may lJ(,

FIe. ~8.

indicated. Fig. 25 ilIustratcs sub-mental development: Fig. 26 iUustrates pro-labial and sub-mcntal development.

These terms seem to the author to far more nearly meet our requirements than the very limited and commonly employed terms. prothagnism and orthognathism, which were in troduced by the

]OKNSON.-A F.£W CONSIDERATIONS IN I'lLLlNG TEETH. 357

craniologist lor describing the variation 01 the facio-cranial angle of man and the lower animals, bllt which are wholly inadequate for expressing the variations caused by malocclusion of the teeth and asymmetrical development of the oones and muscles of the face.

Judgment and practice arc necessar,Y in making use 01 this line in order not to mistake the mal-conditIon of one region for that of another. As, lor example, in that class 01 cases of malocclusion represented by Fig. 27, the mistake is commonly made of suppos­ing it to be pro-intermaxillary development, while in reality Ihe development is, in nearly every case, sub-inferior maxillary, as is proven by Fig. 28, which represents the same face after treatment. This consisted principally in sliding the lower jaw fo!'Ward to obtain normal occlusion of the teeth, which was made possible by first establishing harmony in the line of occlusion, as descrihed under treatment of cases of malocclusion belonging to Class II, Diyision 2, a.

All who hope to attain real success in the correction of mal­occlusion should cultivate a love for art and the beautiful, and form the habit of observing and carefuUy studying the normal and abnormal lines of the human lace, together wi th thei r relations to and dependence upon the occlusion of the teeth. An appreciation and intelligent application of the principles of art must ever go hand in hand with the successful practice of orthodOfllia.

The ease and certainty with which teeth are no .... moved by means of modern regulating appl iances has opened up great possi­bilities in this field of facial art, and there can no longer be jnst excuse for ignoring this most important phase of the subject.

A FEW COItSIDERATIOHS IN FILLfNG TEETH.

BV C. N. JOIINSON, I..D.S. , D.D.S., CHICAGO, ILL.

(C"",In"od I,,,,,, po~~ .. ,. )

MALLETS AND M ALLETI N(;.

THE selection of a mallet for the insertion of gold is a matter which must be left largely to the individual preference of the opera­tor, and yet there are distinguishing characteristics related to the different forms of mallets that caU for consideration. Laying aside the factor of personal equation, we mnst not ignore some of ~he fundamental qual ities inherent in the natnre of the appliance which influence its practicalntility.

TilE HAND MA LL ET.

This mallet was the first to be used for condensing gold, and it would seem to-day to be capabfe of a wider range of sen'ice than any other single form of mallet. No other mallet yet snggested has so many advantages with so few disadvantages. Its chief l!mi­tat ion relates to the necessity of employing an assistant to mampu­late it, owing to the fact thaf the operator has too many uses for