Differential orthodontic diagnosis and treatment planning

Differential orthodontic diagnosis and treatment planning

Differential orthodontic treatment planning ALLEN C. Allentown, Pa. BRADER, D.D.S., diagnosis and M.H. THE test of time and accumulated clinic...

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Differential orthodontic treatment planning ALLEN

C.

Allentown,

Pa.

BRADER,

D.D.S.,

diagnosis and

M.H.

THE test of time and accumulated clinical experience leads the orthodontist toward the inevitable conclusion that the Angle classification of dental malocclusion is inadequate for the diagnostic evaluation of complex dentofacial problems. In point of fact, most systems of classification suffer similar limitations of oversimplification. There is developing within the central channel of the stream of orthodontic knowledge the swelling agreement that facial patterns exist as variables independent of malocclusion classes. Existing cephalometric evidence readily demonstrates that similar dental classifications, premised as they are on mechanical intercuspation of teeth, can exist within a wide range of skeletal types and that, conversely, one may find almost any of the malocclusion classes within the composite framework of a single skeletal t,ype. I propose that the purely mechanistic dental classification of malocclusion must soon be incorporated into and superseded by the larger conceptual scope of vision embraced by a whole new system of skeletotyping-the development of classes of anthropomorphic composites. Records and methods are presently available and the work is already under way. With increasing acquaintance with orthodontic patients, it becomes apparent that ranging individual variation and multiple combinations of characteristic traits preclude the division of the dentofacial complex and dental malocclusion into categories as simple as one, two, three. Nor does the orthodontic treatment of a case so classified fall into place with equal simplicity. While Homo sapiens is clearly recognizable as such, each dentofacial complex exhibits morphologic and anatomic variations which differentiate the individual from the other members of the species. It is commonly held that recognition of these variances serves as the foundation for orthodontic diagnosis. It is the useful integration of subtle intraclass distinctions which refines our case analyses and improves our treatment planning. A point to observe here is that Presented Washington,

806

at

the annual D. C., Jan.

meeting 10, 1965.

of

the

Middle

Atlantic

Society

of

Orthodontists,

Dijferential

dicqnosis

and treatment

planning

8 07

each additional factor requiring evaluation complicates the processes of logical thinking upon which the best attainable treatment plan is premised. It is in this respect that the seventy-odd ccphalometric analyses have largely failed in their intended purpose. They fall of their own weight, In addition, it has never been possible to establish clearly the consistent relations between the individual measurements, per se, or between the significant ones and purposeful clinical implication. What. we call diagnosis or case analysis must cvcntually contribute premises and discrete conclusions to the purpose of clinical treatment. However considered, diagnosis is the point of departure for prognosis. Most orthodontic texts are in fairly close agreement about basic elements to be considered in case analysis. One representative textbook1 lists the diagnostic aids for developing diagnostic criteria as follows: case history, clinical examination, plaster casts, intraoral radiographs, ccphalometric hcadplates, and facial photographs. Many orthodontists make an effort to accumulate at least those records mcntioncd. From that point forward, these criteria exist in hit-and-miss communication with each other and their relationship to the reality of appliance management is marginal at best. Recent publications and meetings reveal diagnoses hinging upon a few common fact,ors, ranging in scope from a single CePhlomctric angle to four or five items considered together, to numerous cxtcnsive, complicated, and confusing cephalometric analyses. Orthodontists generally agree that competent treatment planning constitutes about 90 per cent of the task of orthodontic correction, with mechanotherapy making up the rcrnaining 10 per cent. It is an orthodontic foible to consider that in clinical experience these percentages arc ordinarily reversed, with mechanics receiving the bulk of attention. Many are prone to treatment decisions (including extraction) based on the certain knowledge that a, given appliance philosophy dictates the trcatmrnt procedures anyway. Thus apnears the situation that prompted the present study, which might bc entit’led “An Analysis of the Relations of Diagnostic Criteria.” It seemed worth while to investigate closrly the obvious gap between what is generally said about diagnostic procedures and what is often done about them. lvhat, then, are some of the problems in conducting a full-scale meaningful and differential appraisal of orthodontic diagnostic criteria’? First, not ecery fa.ct,or thnt we a,gree is important is truly meanivful. Chviction is lacking in the consensus that, certain estimates are diagnostically useful. For example, some orthodontists doubt that cephalometric measurements have any diagnostic value. Others lean heavily on ccphalometrics and have the doubtful satisfaction of selectin, v from seventy-odd systems as outlined in the Krogman-Sassouni Syllabus.2 Much in tht literature reitcratcs the acknowledged importance of muscular balance. How does one estimate muscular tonicity, much less consistently incorporate such an estimate into a treatment decision ? Second, there is qLnc.ertainty about the standards fw compnrisow. The poillt is wc]l made that biometric norms may he useful from which to evaluate dysplasias but are not necessarily valid guides toward which to treat individual patients. Perfect occlusion may be the ideal, but functional adequacy is the

808

Brade,t

goal. Relative, but in another direction, what is the gcomct,ric plant or point from which measurements may be made for srria.l ccphalometric study and Wmain reliably unchanged throughout, t,hr scrirs! Some orthodontists rally OII thrw limitations of method to rcjcct categorically all crphalomctric informat,ioll. Thcs tool is admittedly coarse for the fine measuring that WC:desire:. (~“c~~)l~alol~reti~ic~s map be misleading at, times, but, for the present, it is the least mislrading thing t.hat WC have. Third, no clrw stateme& of I&.~ exists (IA to the r*elati~*r i?)lljot.t(o1ce o]’ contradictory d&bgnostic observation.~. I )ocx arch-length dcficirncy ovcrrulc YCcessive facial outline in extraction decisions! Is intrrcanine width always immutable if growth is incomplete? Is this the grnc~xl rule> or do t,lte cxccptions deserve an csplanation ? How does OIU~ clccidc to rcstorc dentofacial outline in the face of severe muscular imbalanrc! Fourth, dia,g?zostic ir~formntion is ,Si?lll/l,tJ inconqdet~. JVlliit do WC reall? understand about anticipated growth? JVill growth occur? If so, when. in what direction, and how much ? (-‘an we say a great deal more about, growth changes than to speak in generalitits like the old clich6 that good faces remain good (with growth) and poor faces get worst (but occasionally they too will improve) I How man)- decisions are based on dinid hunch, whatever that means! %%o here wants to accept premiums on politics insurin, 1~tooth stabilit\- in the postretention periods! It is incumbent upon the prot’cssion to continue searching out answers to these questions if orthodontics is to mature. When so~ncday, we arc at last ahlc to I*ccognizc and classif>- the craniofacial “type” of the individual patient, cvaluatc~ the dcprce of the dysplasia, classif,v the dental malocclusion, understand and alter the influence ol’ mI~scular clnvironment, estimate t,hc anticipated growt,h changes, and suprrimposc upon these, knowledge of the nature and extent, of ~wpo~wrs attainable by differtbnt orthodontic appliance procedures; then, and only thrkn, may WC undcrtakr trcatmcnt of dental malocclusion with increased confidencr in our mtl result. Fifth, orthodontists we inundated with u. IYAWW of data. The mathematics of permutations and combinations yirltls a.stronomicaI numbers when thirty. forty, or more variahlcs are considered sirrlult;lnrousland in relation to cacll other. lt is little wonder that record charts prow invcrscly with practice ~olumc~. *Sixth, hus,?~ cliniciwn6 are pressed for time. Is the role of the orthodontist primarily that of a diagnostician, or is hc cons~mcd in the fire oI’ mcchanotherapy $ The tecliniqucs of ccplialorlict,t,ic stud>- arc archaic ant1 rcs~llt, in biostatist,ical assumpt,ions based upon rclati\cl;. small sample size. 1 know of onI?one study where N = 1,000.” The anthor oE that study has alwa,vs strcsscd t hc importance of th.itAin,g tcct h straight. as opposed to cvcr more complicated mechanics. Sevetzth, syllogistic h~ic is n.ot nece.ssnril~y th,e prero,gati?~e of’ crz’er!~ dentist, nor even of the gifted ones on successil~c d~y.s or zcePi&. Thinking

ortho-

tends to be conditioned by recent observations and cspct*icnccs. The purpose of this article is to attack these ~IY~~~~cI~s, individually and collectively, in a three-pronged fashion, as follows: I. To lay out visually an array of all conceivable (and inconceivable,

Diferential

diagnosis

and

treatment

planning

X09

810

&ruder if you will) orthodontic diagnostic criteria in an effort to label t)hem as follows: (a) useful at this time, (b) meaningless at the present time, and (c) potentially useful in the future if augmented and supported by projected studies (Table I). Those labeled useful, by consensus, will be given an arbitrarily dcsignated weight of relative importance and a reasonable sequential order for consideration in a routine diagnostic procedure. Those labeled meaningless will be relegated to the wastcbaskct as they deserve. Those labeled potentiall,v useful will be it,cmized and made available to members and graduate departments of orthodontics represented here for integrated future research as intrrcst and time permit. II. To suggest the potential for application of clcct,ronic computing machinery to the solution of specific problems of diagnosis and to describe their manner of operation. III. To develop a rationale for one possible procedure of case analysis and to subject that procedure to tests against, stored treatment rxpcricncc. The object,ive here is a projected field testin g of criteria in relation to clinical usefulness and fundamental concepts (Tables 11, 111, and IV). GENERAL OF

CONSIDERATIOKS

ORTHODONTIC

IN

SELECTISG

ELECTRONIC

MACHISERT

FOR

THE

TASKS

DIAGNOSIS

Clearly, then, there is need now for increased, morr accurate intelligence in orthodontic case analysis and treatment planning. Intelligence is defined as the ability to learn or understand from experience, the ability to acquire and retain knowledge, and the ability to respond quickly and appropriately to new situations resulting in the successful performance of tasks. Presently available electronic computers are capable of performing these several functions rapidly and with accuracy far exceeding those of intelligent human individuals. An ECA expert estimates t,hat 2 minutes on a computer equals 50 years of pencil work, 8 hours a day, in a 40 hour week. Bits of data are moved in nanoseconds (billionths of a srcond). It may now be timely to explore orthodontic applications for such machinery. The electronic computer performs logical mathematical operations on meaningful input information and yields output answers according to a specific program of instructions. There a.re two main classes of computers: analog and digital. Analog computers simulate problems and can perform arithmetic computations indirectl,v by mechanical or electronic devices whose measurements are analogous to the numbers of the problem. Digital computers operate by numerical counting with electronic speed and remarkable accuracy. The digital typo is best suited for handling numerical problems, statistical data, and logical processes and may be the better suitrd of the two types for orthodontic applications. Digital computers, in simplest terms, consist of components which accept, store, manipulate, recognize, and interpret two discrete stat,es of electrical

Differential

l-o?uwLe 51 Nwm her 11

diagnosis

and

treatment

planning

8 11

Table II. Case analysis Case

NaIl1e I.

CLINICAL

DATA: 4. Height: 5. Weight

1. Age: 2. Sex: 3. Race: OTHER II.

III.

:

:

INTRAORAL Decayed Missing IJnerupted

8 8

No.

X-RAY

EVALUATTON:

I 8 I 8

MODEL

ANALYSIS

1. Classification

: of

occlusion

2. Individual

characterization

(a) (b) (c)

Spee

Overjet Overbite Curve of

3. Arch

length

(a)

Maxilla

mm.

mm.

(b)

Mandible

mm.

mm.

4. Tooth (a) (1))

(a) (b)

DEFICTENCY

size Individual teeth Sum of mad. “6”” Sum

6. Arch

EX(‘ESS

of max.

x 100

Mean

“6”*

Range

=

77.2 =

74.5

- 80.4

symmetry Midline Clinical

relationship evaluation

of

1 13

I

1 to

facial

plane

phenomena-on and off, pulse and no pulse, 1 and 0, or, verbally (yes and no). Thus, they employ a binary system or variations of this rather than the decimal system of arithmetic. The computer manipulates its bits of information through complicated internal circuitry or programming by means of sophisticated switches or gates which, in series, parallel, and in various combinations, perform complex and logical arithmetic computations. Most important to orthodontists is a consideration of the tasks that can bc performed in our areas. Although the computer reduces all mathematical problems to simple arithmetical counting procedures, it can handle additions, subtractions, divisions, multiplications, roots, and even the most difficult equations of calculus. Its capacity to perform drudgery accurately and with lightning

speed is its chief asset. Its chief limitation is the nerd t,o program the prohlcrt~to think through and test the logic of the prohlcm at, hand. Explaining from the general to the specific thv capacities 01’ wmputc‘rs to mwt, the present limitations of orthodontic analysis as prwiously gi\cn, digital computers can accept volumes of data. They wn sort and stow it with irrfallihl(~ memory. They are cxpcrt at c*onsidcrin g mnltiplc variables in logical scv~uc~ncc~. They can run through lwgthy rn~~thc~matic~alprograms in little time without confusion, and they can derive logical wrrclusions from the Itlil%(’ without cr1’oI’ in reasoning. More sprcificall,v, applications ot’ thrsc skills to orthodontic prohl~ws ar(’ pivhablq’ practical. SI’E(!WJ(:

(IONSIDERATIONS

IS

DEVELOJ’ING

CO~II’IT’I’ER

FROGRABJS

FOR

ORTF1ODOS’I’I~

DIAGNOSIS

First, Ict us consider t,he entire p~*ohlem of orthodontic diagnosis or intlivitlual cast’ analysis. Three arcas of initial prrparation arc wquircd : 1. It> is necessary to drrivc a program for computer analysis. To do t,his! WC’must decide initially which diagnostic f’avtors arv mcaningfnl and

vozume

51

NuwaBer

11

Diferential

diagn.osis and treatment

planning

8 13

Synthesis

Table IV. Arch

/

length

Extraction Deficiency

Maxillary

Spacing

(i)

or

C-J

o-5 mm. 5+ mm.

Mandibular

0 to 5 mm.

5+ Anchorage

Labial

Headgear

musculature

Required

incisor p E

Lip

mm. only

Class II mechanics with elastics

TIypotonic

Hypertonic

Expansion Ihpansion

Contraction Contraction

positions to to

A-PO r+

postures

Anterior

to 9”

Posterior

to

“E”

and reject those which are valueless for lack of objectivity or because of irrelevance. 2. We must relate factors to each other in some sequential order, similar to the way this function is performed in the orthodontist’s mind. Relative importance of items and reconsideration of items will likely result in a side loop program structure. 3. We must test our thinking and, by such testing, accept the conceptual reality of some diagnostic process. No doubt some arbitrary assumptions will be necessary to initiate a program. It is difficult to analyze the thinking process that occurs whenever a new case is diagnostically considered. What tests do we make mentally? In what order do we consider items? And how are decisions derived! It is important to attempt to establish such order in the interest of self-education and improvement of future decisions. NEED

FOR

PRELIMINARY

PROGRAJI

SOLUTIONS

Perhaps all this is trying to run before we have learned to walk. In this possible contingency, many initial computer applications may be necessary as preliminary solutions before we can proceed with the entire diagnostic problem. Consider, for example, a question previously posed. What plane or point represents a reliable reference for serial cephalometric work? Computers have already solved similar problems in other areas. Given a plane with N points on it, how do we determine a center when the points change position as independent variables of a function of real time? This is clearly a problem in calculus, and it is difficult when N may equal 50 ccphalometric landmarks. Such a problem bccomes possible of solution in computer application. Consider the problem of occlusion of twenty-eight morphologically variable teeth along several acceptable arch forms in three planes of space. Consider the problem of the relationship of arch form to tooth size and to arch length.

814

Brader

Consider the problems of growth estimation of independent basal ~OIWS. Projection of plotted regression curves and mat,hematical probabilities arc passible. Instead of nibbling at these questions with piecemeal studies of small sample size and with laborious hand labor techniques, is it not time to scan original head films directly with photosensitive tubes (pat.tern recognition) and increase the sample size to the thousands of films (pretty well standardized) on file all over the country and let the programmed computer derive sonic answers to our uncertainties about growt,h and treatment? These procedures are now entireI> possible and have been initiated at some institutions.*-” Consider, once again, the problem of varyin g tissue responses to mechanics. Add the variable of different appliances. Add the variable of different malocclusion classes and the intraclass variables. ,4dd the variable of different timing. Multiply by thousands of serial films on treated cases. JYhat do we have? Clearly, a computer problem. I have made no effort to get involved here with the postulates of Boolean algebra,7 which is a form of symbolic logic conforming to algebraic laws and leading to conclusions of truth values of propositions. I have rather carefully avoided the enta.nglement of electronic circuitry and components as utilized in computer construction. Such sciences are in an advanced state and are available for independent study.” STEPS

IN

PROGRAM

DEVELOPMEST

In an effort to promote interest and effective contribution to the derivation of a programmed approach to orthodontic diagnosis the following steps” are given : 1. Numerical analysis. Reduction of complex problems as integrals, differential equations, continuous functions, etc. to simpler terms acceptable to the available computer equipment. 2. Programming (flow charting). Construction of a visual block diagram to describe the steps of the procedure and test them for reasonable order. Flow charting is the drawin g of a graphic record of the planned logic of the computer program. It spells out the exact sequence of operations on the data and the choice of alternatives at points of decision. 3. Coding. Writing of detailed machine instructions in language that the machine can interpret and react to. 4. Checkout. Running of sample test problem to correct errors. For your consideration and the application of flow-charting principles in keeping with the described objectives of this article, I invite your attention to the key, given in Table I, where : Outer ring = multiple individual criteria. Middle ring = basic decisions to be made. Inner core or column = objectives and key. SUMMARY

AND

CONCLUSIONS

The material presented here must be considered in the nature of a preliminary report. It has evolved from the observation that electronic techniques

Volume

51

Diferential

Nunzberll

diagnosis and treatmew t planning

8 15

and equipment now available may provide the means for achieving consistency and excellence in the complex tasks inherent in orthodontic diagnostic procedures. This article has presented a concept which proposes classification of cephalometric skeletotype (classes of statistically derived anthropomorphic composites) for the purpose of total description of the dentofacial complex (including independently related dental malocclusion classes). Orthodontic diagnosis and treatment planning are based, in part, upon the recognition and understanding of dentofacial class variances. However considered, diagnosis is the point of departure for prognosis. Present diagnostic deficiencies are enumerated in seven categories: (1) meaningless estimates and irrelevant criteria, (2) uncertain standards for comparison, (3) contradictory diagnostic observations, (4) diagnostic information that is incomplete, (5) voluminous data, (6) time limitations and outmoded techniques, and (7) illogically derived decisions. An array of conceivable orthodontic diagnostic criteria is presented for evaluation (Table I), and a sequence for consideration of diagnostic criteria in t,reatment planning is offered (Tables II, III, and IV). The application of elecbronic computing machinery to the solution of orthodontic problems is suggested and described. The need to develop computer programs is discussed, and the ability of the computer to test diagnostic procedures against accumulated treatment experience is pointed out. An order of attack on the total diagnostic problem is presented. Steps are described for initiating program development. It would appear that, clcctronic techniques and logically derived computer programs arc essential if orthodontics is to keep pace and to mature with thr present explosions in population and technology. REFERENCES I. Graber, T. 31. : Orthodontics-Prineiplcs and Practice, Philadelphia, 1961, W. B. Saunders (‘ompany. 2. Krogman, W. M., and Rassouni, V. : A Syllabus in Roentgenographic Cephalometry, Philadelphia, 1957, Philadelphia Center for Research in Child Growth. 3. Ricketts, R. M.: A Foundation for Ccphalometric Communication, AK J. ORTIIOIH)NTICS 46:

330,

1960.

4. Walker, Geoffrey F.: Orthodontics and the Computer, Philadelphia, 1965, Philadelphia Center for Research in Child Growth. 5 . Drake William B . . Preliminary Evaluation of the Automatic Scanning and Digitizing <, of the Lateral Ccphalographic X-ray Tmage, M.S. Thesis, Graduate School, Temple University (unpublished). 6. Parkinson, William: The USC of Electronic Data Processing in Simulation and Problem Analysis of Orthodontic Study Casts, Senior Thesis, Graduate School, Temple University (unpublished) . i. Berkeley, E. C.: Symbolic Logic and Intelligent Machines, New York, 1961, Reinhold Publishing Corporation, pp. 20-61. 8. Jacobowitz, Henry: Electronic Computrrs, a blade Simple Book, New York, 1963, Doubleday & Company, Inc. 9. 1lcCrackq D. D.: Digital Computer Programming, Sew York, 1963, John Wiley & Sons, chap. 7, p. 87. 13.50

Hamilton

St.