Diagnosis: Rote or reason

Thomas J. Zwemer, D.D.S., M.S.D. Augusta, Ga.

I n a casual discussion with a colleague several years ago, I started to describe a patient I had recently examined. I stated that the boy was 14 years old and had a Class II, Division 2 malocclusion. I was interrupted in midthought by his interjection: “This would be an excellent case for maxillary second molar extractions. ” This curb-side treatment planning startled me into rethinking the art of communication and the mental mechanics of diagnosis and treatment planning. In so doing, I recalled Moyers’ apt observation that “immediate classi- fication prejudges all subsequent thinking.” It was I who had triggered this hasty response from my friend by classifying instead of describing. Indeed, we are creatures of habit, and it takes vital energy to resist the stultifying effects of routine and repetition. Are we seeing our patients? Or are we seeing carica- tures of them in a web of norms, standards, or stereotypes? This is not to dis- parage the norm producers, but to utilize a norm as a template against which to reconstruct a face or a dentition is to diagnose and to treat by rote and not by reason.

Diagnosis may be defined as the decision arrived at or the judgment rendered regarding the presence or absence of abnormality or the adequacy or inadequacy of various observed phenomena.

The primary tools of diagnosis are the senses, their afferent pathways, the human brain, its synapses, and its superimposed faculty of mind, the distinguish- ing feature between man and animal. The mind acts as a biologic computer, collecting and storing data. This is knowledge. The mind further functions to analyze and correlate these data. This is understanding. Knowledge may be possessed without understanding, but understanding is predicated upon adequate knowledge.

The secondary tools of diagnosis are the equipment, the instruments, the records, and the techniques that we utilize to extend, amplify, and supplement the senses and the computer capabilities of the human mind.

Reaction to a stimulus in a fixed stereotyped manner becomes diagnosis by rote, while the efficient utilization of the primary and secondary tools of diag- nosis in a systematic and exhaustive manner to make possible an enlightened rational choice constitutes diagnosis by reason.

As our technology, knowledge, and understanding advance, our responsi-

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54 Zwemer Am. J. Orthodontics July 1969

bilities increase; that is, early recognition and increasingly discreet differentia- tions are incumbent upon the clinician. Modern medicine demands of t,he inter- nist a comprehension of microchemical and histochemical arrays in the isolat,ion and identification of disease at its inception and not in its terminal stages. An equally high level of diagnostic acumen should be expected of the contemporary orthodontist.

Our problem, therefore, is to take a patient, reduce him to his component parts, feed these parts into our analytical machinery, and have them returned to us undistorted and expressed in meaningful language which we can then judge as to their relationship to the desirable. In support of this thesis, let us engage in the orthodontic decision-making process.

Case analysis of the author’s son

Steve is an 11-year-old boy, who was born in September, 1954. He has a leptoprosopic face and a retrognathic profile with the lip encroaching onto the esthetic line (Fig. 1).

To really know Steve, we must also know what he has been-his antecedents and his personal history. Steve’s forebears ranged from Roman Alpine redoubts through the Dutch lowlands to the Viking fastness of the icy north, which is reflected to this day in the cold feet of his mother. Steve comes by his profile honestly ; he looks like his dad (Fig. 2).

His personal history is uneventful except for a tonsillectomy and adenoidec- tomy at the age of 9, which partially relieved a chronic nasal congestion and repeated attacks of sore throat. There is some clinical indication that he has also received a paternal predilection for allergic rhinitis.

Developmentally, as measured by height and weight, he is midstream of his peer group. Dental age, based upon tooth formation, finds Steve also in the central range for ll-year-olds as far as second permanent molar crown calciflca- tion and tooth eruption are concerned, but about 2 standard deviations below the mean when it comes to root formation in the premolars and canines (Fig.

Fig. 1

Volume 56 Num her 1 Diagnosis 5 5

3). His adaptive behavior is somewhat precocious, as testified by his savoir-faire in social studies.

The dental casts show a distoclusal relationship, protruding maxillary inci- sors, an overjet of 5 mm., and an overbite of 50 per cent. Lower arch form is ovoid, with approximately 2 mm. of crowding in the incisor-canine area (Fig. 4).

Fig. 2

Fig. 3

56 Zwemer Am. J. Orthodontica July 1969

Fig. 4

Fig. 5

Arch length-tooth size evaluation indicates a plus 1.4 mm. in the mandib- ular arch, excluding the “E” spaces. A Boltm analysis of the anterior seg- ment indicates a conservative upper anterior excess of 3 to 4 mm. This appears to be due to the large maxillary central incisors (9 mm.) and the small mandib- ular canine (6.5 mm.).

Cephalometrically, the points of particular pertinence are the small ANB angle associated with such a dental configuration and the steep mandibular

Volums 56 Number 1

Table I. Cephalometric data

Diagnosis 57

Reidel Steiner Downs Tweed

SNA 75 ANB 3 Facial angle 78 FMA 28

SNB 72 SND 70 Angle of convexity 5.5 FMIA 55

SN-GoGn 34 1 NA 26.5 A-B plane 3.5 IMPA 97

NAP 5.5 1 - NA 6 Mandibular plane 28 = 1 - RN 101 1 - NB 23.5 Y axis 65.5 - -

1 - 1 127 1 - NB 3.5 Occlusal plane

i - GoGn 97 PO-NB 1.5 l-i 127

i - Occlusal 72 Diff i - Occlusal plane 19 plane

_1 - NP 5.0 1 - i 127 i - Mandibular plane 7

1 - FH 125 Occhsal plane- 20 j- - AP plane 6 SN

GoGn-SN 34

Fig. 6

plane which, in effect, gives added weight to the lower incisor procumbence of 97 degrees. The pogonion configuration, while excellent, is hidden from the! NB line by the steepness of the mandibular plane and the subsequent retrognathic mandibular posture (Figs. 5 and 6 ; Table I).

The lower incisor lies on the A-PO line which, of the assessments utilized, indicated the most favorable prognosis of all. The open Y axis further substanti-

58 Zwemer Am. J. Orthodontics July 1969

Fig. 7

Fig. 8

‘ular ates the vertical growth pattern suggested by the SNA and SNB and mandib plane relationships (Fig. 7).

Soft-tissue profile analysis using the “E” line approach demonstrated lips generally associated with bimaxillary protrusiveness. Furthermore, clefting or accentuation of the lower lip sulcus indicates a lack of anterior tical face development (Fig. 8).

full the

ver-

Hyoid bone levels and tongue posture do not reflect the mild fun&i onal problem associated with the chronic nasal congestion. It might be well , in

Diagnosis 59

passing, to observe that variation within pattern is the rule in myodynamics as well as in skeletal configuration. To be dogmatic or narrowly rigid in one area or the other is to be equally bigoted.

Summing up our observation of this young man, we find a boy midstream of his peer group in growth and maturation following a genetically determined facial and dental pattern favoring the paternal inheritance, which is character- ized by a retrognathic mandible and mild dysplasia in tooth material with a superimposed distoclusion of the buccal segments, an overbite of 50 per cent, an overjet of 5 mm., and adequate lower arch length. As a parent, I love this face; yet, as an orthodontist, I see deviation from the desirable. Therefore, I must return a judgment or diagnosis of malocclusion as described above. Fur- thermore, my observations have been quantified to the extent that I can now proceed to classify and to plan treatment.

To group this patient with others of similar type would be classification, not diagnosis. Outlining therapy to improve occlusion and facial contours requires the prior step of defining in equally descriptive terms the treatment goals, which is beyond the scope of this article.

It is, however, only upon the basis of adequate observation and description that proper diagnosis, classification, and treatment planning are possible. Hav- ing taken this first step with reason, we are now able to face the equally chal- lenging step of treatment planning with confidence, with the assurance of a rational base for our deliberations.

Medical College of Georgia School of Dentistry