Applying the clinical yardstick to some current orthodontic concepts

APPLYING

THE CLINICAL YARDSTICK TO SOME CURRfENT ORTHODONTIC CONCEPTS

BERCU

FISCHER,

D.D.S.,

NEW

PORK,

N. Y.

My business is to teach my aspirations to conform themselves to fact, not to try to make facts harmonize with my aspirations. Sit down before fact as a little child, be prepared to give up every preconceived notion, follow humbly wherever Nature leads or you will learn nothing.-Thomas Huxley. INTRODUCTION

A

LL biologic knowledge consists of two parts. One is the aggregate of experimental observations and thinking derived from biologic experiments; the other is the language used to communicate these activities. This growth process of knowledge is common to all biologic disciplines to which the orthodontic specialty belongs and is a most useful means for sharing and advancing such knowledge. A glance at the growth of biologic knowledge is sufficient to show that each of these divisions can get out of hand and hinder progress. Turning to the orthodontic field, accumulated clinical experience very often outstrips current usage of the language, making it difficult for the orthodontist to say clearly what he means. While this does not affect his doings, it does slow down exchange of ideas. At other times the language outstrips clinical practice. Serious confusion may result if this gets out of hand. Time will not permit us to give a full account of the periods of divergence and convergance of these two divisions of knowledge in orthodontic history. However, since this article is about orthodontic concepts, it is important to point out a few fundamental data. When the field of the orthodontist was restricted to the teeth, the problem of bringing the orthodontic language in line with orthodontic experience was relatively simple. Angle’s classification of malocclusion may be considered as marking the end of this period. Fascinated by its simplicity but overlooking its limitations, orthodontists accepted it as a basis for diagnosis and treatment. Thus, a classification useful for assorting certain observations has been extended as a schema for general clinical practice. Orthodontic literature shows that one of the main activities in orthodontic methodology of the period during and after Angle centered around the New

Read York,

before The Society for N. Y., April 30, 1964.

Dental

Research,

362

New

York

University,

College

of Dentistry,

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for~mulation of a normal standard t,hat wodti ~‘t~])la,ct: iiJl@t”~ CCII~W~~ of ’ * JIOI’m al occlusion. ’ ’ Of the standards offerctl as subxt,it,ut,cs, some were forlrlulilted on the lmsis of anatomic parts or Ia t~tLl~~arksother than the t&h, ~n(+h as the key ridge. Others were tlerivctl statistically from data obtainc‘cl front so-called - ‘ r10rrna1’ ’ individuals, that, is, norn~s l)asetl upon anatomic Ianti. marks, such as the “canine law” of Simon. Thc~ most important single oC)servation about these substitute methods of tlia,ynosis is in their relation 20 treatment. While they were developed because of dissatisfaction with Angl(,‘s tliagnosis. t,hey produced no appreciable change in his methods of treatment. The basic orthodontic tooth movement--cln maxsc rnovernent-rcmi~i~~~~(~ unchanged. The name of Calvin X. Case comes to mint1 as the outstanding opponent to Angle’s concept. dngle had established the full complement of teeth as ant of the basic principles of practice. This was inviolable and carried with ii the injunction, “Thou shalt not extract !” (:nse advocated extraction of teeth in the treatment of some patients; and in this controversy, as so often happens, the est.ablishecl practice carried moral weight and won. The organizt>tl profession and public opinion then did the rest by compelling the ranks I G: fall in line. Thus, Case’s teachings soon were brushed aside, removing the, only important obstacle to the perpetuation of the> Angle concept. Some of you may recall a repetition of this controvtlrsy when Paul .Sim,nr of Germany advocated the extraction of maxillary first premolars in the trclat ment of (Ilass II, Division 1 (Angle) malocclusions. Since biometric norms arch still with us today, it would seem, in retrosl)ect, that the investigations which finally, and for good reasons, invalidated Simon ‘s “ canine law” were mot ivatcd more by a desire to counteract extraction than to assess his met hot1 tJ1’ tliagnosis. -\\Tith the full complement of teeth dominating clinical practice, orthcrdontic failures led to two important consequences. The first, was the increasing interest that the orthodontist showed in the disturbing effect of orthoclontic tooth movement upon contiguous facial structures. The seconcl was his concern over the instability of the teet,h after t,reatment due to t,he action of these same contiguous parts. As the activities of the ort,hodontist, WVI’( thus extended, first to the dental arches, then to the tissues immediately su I’rounding them, and finally to more remote structures, the problem of equ;lting orthodontic reality with Angle’s orthodontic voncrpt hecame progrrssivrl! more difficult. Our attention turns to the various applianctls developed by Anglr for thc& purpose of correcting the disparit,y between his theory and practice, endin< in the presentation to t,hc profession in 1929 of his “latest and best o~*thc+ dontic appliance-the edgewise. ” About this time, Charles H. Tweed revived t,he issue of extraction and iu 1936 published some creditable results obtained in cases in which he estractetl teeth. The human mind, naturally given to rat,ionalization, dots not ptlrrnit work to continue for any length of t,ime before cvncepts begin to rnakc their

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way into this rationalization, It was such concepts as facial esthetics as a standard of normality, the position of the mandibular incisors, intraoral stationary anchorage, and the tooth movement claimed by Tweed’s method that orthodontists soon began to question. THE PROBLEM To bring this parallel review of orthodontic concepts and clinical reality up to date, we may note the following : (1) While extraction of teeth in orthodontic treatment is generally accepted, it is still under the effect of Angle’s injunction in some quarters of the profession. It is difficult to understand why resection of the mandible for the benefit of the patient is considered good orthodontic practice, while extraction of teeth for the same purpose is not. (2) Orthodontic literature is replete with concepts such as theories, hypotheses, philosophies, etc., which are still waiting to be equated with clinical reality. To this must be added (3) the influx, into the language of the orthodontist, of terms and statements from collateral disciplines such as anthropology, genetics, endocrinology, etc. These collateral disciplines have not yet equated these terms with their own reality. (4) Orthodontic diagnosis has drifted further and further away from treatment and has continued its own development without the benefit of clinical verification. I-Iaving been brought up on an unjustified optimism that anything desirable in clinical orthodontics is also attainable, we have allowed the simplicity of techniques employed in formulating standards of ‘(norms” to transcend the complexities involved in their application to the individual patient. Surrounded by such a mass of conjectural a,nd unsettled opinions, the clinician is bewildered as he tries to apply some of these in his daily practice. They invariably lead to the formulation of indiscreet objectives of treatment which are unattainable with available orthodontic means. In presenting this sketchy outline of the orthodontic scene, it is not my intention to belittle valuable cont,ributions to our knowledge. Without these, progress could not have been possible. On the contrary, it is concern for the loss of valuable clinical experience in what might be called the “battle of the The most disturbing result of concepts” which prompted this presentation. periods in which concepts get out of hand is the division of professional ranks into groups siding with and defending the totality of pet concepts. It is not the defense of valuable clinical reality contained in a new concept that is objectionable, but the defense of its totality and its panacean claims which crowd out some well-established and experimentally verified practices. Such a situation not only hinders progress, but shakes the confidence of the clinician in his own work by placing him in a defensive position and very often causing The only reason for bringing these obhim to discard valuable knowledge. servations to your attention is the desire to share with yen my conviction that a good deal of the misunderstanding and confusion today, as in the past, has been due to the disparity between what we do and what we say in orthodontics, and to suggest a solution.

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In spite of the complexity of the problem which confronts us, its OVWwhelming importance warrants our analyzin g it as objectively as possible iI1 order to understand something about the following of its aspects : (1) (2) reality. 131 (4)

The origin of orthodontic concepts. The conditions which contribute to their

separation

How to prevent concepts from getting out of hand. ITow to distinguish between real and unreal orthodontic

from

clinic~:~1

concepts.

Origin of Orthodontic Concepts-The orthodontist, creates his own littIc% universe, within which his orthodontic activities lead him to discover cer’t.aitl facts and phenomena. His mind is on the constant, lookout for concepts to generalize and pattern these discoveries. Such patterning is encouraged by the abilit,y of the human mind to find or establish rela.tionships between things and phenomena, even when such relationships may not be Nature’s intention. Thus. the orthodontist postulates such concepts as classifications, hypot,hcscls, definit,ions, philosophies, etc., and here is where thr trouble bclgins. There arc a number of conditions which make it possible for concepts to get out. of hand. Some of these are inherent in the nature of concepts; others have their basis in the human clement ; still others originate in t,he st,ruc+uro of language. Conditions from these sources c*ombine to brcloutl and ol~urr the basic facts underlying the concepts ant1 irt’c mostly responsible for WUIcepts getting out, of hand. Ifoul Concepts Get Out of Hand.-Let us analyze for a moment how a concept, drifts away from its frame of reference. 1:y “frame of reference” we mc3a.n simply a set of observations with referrrlce to which the concept, is defined. The orthodontist employs the term “dentofacial complex” to designate the biologic field in which he works. When he uses this term, which sounds all-inclusive (and it is), does he really see ant1 know the whole CWIIplex:’ The truth of the matter is that the orthodont,ist becomes acquainted only with certain fragments of his biologic fieltl, at best coming in conta.c+t with only a, limited number of rela,tionships between the anatomic Itarts of the clentofacinl complex and their functional activities. If such a loose collecbion of fragrncnts is considered the whole franrc of rc~frrcnce. no harm need result from having a concept. The important thing to remember is that the concept and the t,crm used to dcsignatc it wcw formulatetl upon relationships and phenomena discovered in the partieu1a.r fieltl of The wortl “concCpt,” however, is not operat,iorrs and applies only to them. always associated with such a modest, claim. Very often it is used with reference to the whole biologic complex to which the isolated fragments belong; and the fact that it was only these fragments upotl which t,he c*oncrljt was originally formulated is forgotten. This can be made clear by an illustration. Take Angle’s definition of Class II, Division 1 malocclusion. Two traits-the molar relationship and the

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anterior overjet-are the only criteria upon which the definition was formulated. If Angle had limited his concept and term of this class to cases with regular dental arches and the t,ypical Class II molar relationship and overjet, he would have confined the colicept to the original frame of reference ant1 everything would have been clear. But difficulties and confusion developed because the term was employed to include traits which were not covered by the original frame of reference. This tendency, when making statements, of extending the meaning of terms beyond their frame of reference and making them all-inclusive contrihutes greatly to the unreality of concepts. Contributing t,o this tendency to generalize is a human element known as “wishful thinking” which allows concepts to influence objectivity of jndgmerit. Unless continually checked against clinical findings, “wishful thinking” is likely to start unconsciously. Nature and Biologic Concepts.-Another factor contributing bo the divergence between concepts and clinical reality is the relationship between Nature and biologic concepts. Due to the structure of some biologic terms, their use implies a partnership with Nature in experimental activit,ies which are man’s alone. Take, for instance, the term “normal.” All standards of normality used by orthodontists imply their being a part of Nat,ure’s plan for the person to whom they are applied, an assumption having no foundation in fact. This assumption originates in the belief that what is desirable is synonymous with ’ ‘normal. ’ ’ Nature’s resistance to some orthodontic operations shows that she neither asks for nor always approves of them. The orthodontist very often is bogged down by Nature in his work until he discovers her int,erfercnces and his own lirnitations. By recognizing these limitations, the clinicin?~ can cqery often enlist Nature’s assistance in the attainment of what is desirable. This is the “achievable optimum in, trelatwlent.” Let me clear up another point about this relationship between Nature and biologic concepts. The various schematizing methods of diagnosis employ standards which are derived statistically from measurements taken upon samples of so-called “normal ” individuals. These biometric norms differ only in the criteria. which dictate the choice of dental, facial, and cranial landmarks used in obtaining their measurements and in the form of their final yardstick. Sta.tistical yardsticks or standards may take the form of tables, graphs, lines, angles, diagrams, wiggles, etc. On first acquaintance with these various methods, one gets the feeling of having come upon some very valuable practica.1 guides to treatment, and This first impression is not at all every one of these standards seems right. surprising, since the various standards are correct with respect to the set of observations with reference to which they were defined. However, confusion follows when objectives of treatment for a particular individual are formulated upon such standards. The standards become clinically meaningless for a number of reasons, two of which are relevant to this discussion. First, the parts of the individual to which the standard is applied have in common with

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the parts of the constructed art~ifieial model 01’ standard only t,he names. ()nt! Second, tlue t,o natural varintiorl. is living tissue; the other is inanimate. symmetry between the component parts of complex 01gans is practically non existlent ; asymmetry is the rule, The various natural asymmetries are greatly responsible for the individuality of each dcntofilci;rl complex, arc usttally bilateral, and can be diagnosed only by coml)aring right and left homoloaous parts of the same individual. Because of the moth in which it is constructc~tl. the biometric norm has a,lready leveled off without benefit of treatment, rnan~ of tho asymmetries which were present in the intlividuals of the sample arl(l presents now a meaningless model for their diagnosis. The unreality of these schematizing mrthods of tliapnosis which tlominat (b the orthodontic scene today is further seen clearly in the following instance. Dental and fa<*ial esthetics. which play such an important, part in formulating ob,jcctives of orthodontic treat,mcnt,, necessarily influcncc the choice of the prototypo and statistical sample upon which the biometric norm is constructc(l. If we stop to consitler that Nature produces correct occlusions in people of all t,ypes and races. we must conclude that an esthetic effect. unlike function, is not one of Nature’s objectives. M’hiic it, is cl;~sy to aclmit I hat, ;Ln csthvtic sense is inherent in man, it must be rrrognizrtl that its ccmcrete expressions ill’<’ iiot biologic nl;nlifcst;ltions, but are cultural iul(l anthiopologic. Thcsc (‘sl)ressions tliffcr with various cultures and races, various localities, and historit* ln~riotls Of nliL11. A bimaxillary protrusion, pt’ot~raction, or prognathism (dirferret, terms mea.ning the same thing) is :I rtilttt~~;~l trait. and nmy even be i\ criterion of beauty in some ethnic groups in this country. When t,ho sani(h trait OCCUPS in an individual of another ethnic group, according to some schools of thought, it calls for orthoclontic: interference even when the occlusion is correct. How can anyone be justified in claiming Nat,nre itS a partner in such activity’! It is obvious that thcrc is 110 rel;rtionshil~ between Nature and these concepts. So we see that, once something is isolatctl from a biologic whole, it can be examined and considered by itself from different points of view and COII.elusions can be drawn which seem logical in an abstract exposition, forgetting that what we are examining and studying is not t,he living complex orga,n of the individual. This difference between individuals, between biometric norms and the individual, between norms of various groups or samples (in othci words, this individuality of biologic organs, despit~c their basic commo11 pat. tern) invalidates schematizing methods of diagnosis as a basis for ort,hotlontic~ changes in the individual. What has been said is sufficient to show t,hat intuition and imaginahion enable the human mind to formulate concepts. “Wishful thinking” ant1 personal bias may, through language, build logical structures that have IIO biologic foundation and no clinical justificat,ion. T’ndrr the circumstances, it is obvious that, if we are to avoid confusion, it is necessary to check any ad vance in concepts against clinical reality. The sit.uation points clearly to the

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need for guiding principles which will enable the clinician to distinguish between real and unreal conccpt,s. Such guiding principles a.rc made ava,ilablc by the scientific method. SCIENTIFIC

METHOD

IN

CLINICAL

PRACTICE

A complete discussion of the techniques employed in the application of this method to clinical orthodontics is not here intended. A detailed analysis of it will continue to be made available in my writings.l I do wish, however, to leave for your consideration some of the guiding principles which have developed from the application of the scientific method in my practice. The first group of principles refers to the relationship between the clinician and Nature as it applies specifically to the orthodontist. The second group of principles forms a yardstick which is helpful in differentiating between what is useful and what is worthless for the clinician in general. I stated earlier that, by recognizing Nature’s interferences and by discovering his own limitations, the orthodontist very often can enlist Nature’s assistance in the attainment of what is desirable. Since all natural interferences necessitate some form of compromise for their solution, I deem it necessary to make my own position clear on some aspects of practice relevant to the relationship between the orthodontist and Nature. In any compromise with natural conditions that interfere with my attainment of a correct functional intercuspation between t,he maxillary and mandibular teeth, the following are the remedial steps for nonextraction, as well as for extraction, cases. 1. Never compromise the correct relationship between the maxillary and mandibular canines. 2. While correct tooth alignment and correct intercuspation are important objectives of treatment, these objectives are not to be attained by disturbing the original facial profile line of the patient or by moving the teeth into an area of instability. Disturbance of the facial profile through treatment and instability of end results usually go together. Nor is an improvement in the facial profile line of my patient, at the expense of a correct intercuspation, considered a successful orthodontic result. Good intercuspation and a good facial line are not mutually exclusive. 3. Any tooth imbalance between the various segments of the dental arches should be adjusted (a) by overcorrection, (b) by spacing or crowding, (c) by slicing, or (d) by extraction. 4. A Class II relationship of the teeth posterior to the canine with good intercuspation should be preferred to a cusp-to-cusp relationship. All the foregoing principles of practice have one objective-the attainment of the achievable optimum in occlusion and of stability within the limitations of each individual patient. The second group of principles applies to all clinical practice. It is my opinion that the yardstick offered by the operational approach2 of the scientific

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method is invaluable to the clinician for t,he evaluation of statements. This yardstick recognizes four different kinds of statements : true; false, iwhterminute, and meaningless,3 as defined by Rapoport,. A statement is clinically true if all three of the following conditions arc satisfied: (1) The statement implies predictions to be tested by conceivablr clinical operations. (2) Cl inical operations have been carried out to test the predictions. (3) Predictions have been verified by t,he operations. If the suggested clinical operations hitv(b failrtl to verify the predictions, we will say that the statement is false. If clinical operations have been suggested but not carried out, we will si1) that the statement is indeterminate. If no conceivable operations have been suggested, we will say that the statement is clinically meaningless. To apply t,his yardstick is to witness and hasten the process of changing dental art into dental science. REFERENCES

1. Fischer, W. 2. Britlgman, 3. Rnpoport,

Orthodontics, Diagnosis, Prognosis anI Treatment, Bercu: B. Saunders Company. P. W.: Logic of Modern Physics, New York, 1948, The Anatol: Operational Philosophy, New York, 1953, Harper

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ST.

Philadelphia. Macmillan & Brothers.

J!Gt’. C’ompany.