The decision to extract: Part H. Analysis stated reasons for extraction

of clinicians'

Sheldon Baumrind, DDS, MS, ~ Edward L. Korn, PhD, b Robert L. Boyd, DDS, MEd, c and Raymond Maxwell, DDS d

San Francisco, Calif., and Bethesda, Md.

In a recently reported study, the pretreatment records of each subject in a randomized clinical trial of 148 patients with Class I and Class II malocclusions presenting for orthodontic treatment were evaluated independently by five experienced clinicians (drawn from a panel of 14). The clinicians displayed a higher incidence of agreement with each other than had been expected with respect to the decision as to whether extraction was indicated in each specific case. To improve our understanding of how clinicians made their decisions on whether to extract or not, the records of a subset of 72 subjects randomly selected from the full sample of 148, have now been examined in greater detail. In 21 of these cases, all five clinicians decided to treat without extraction. Among the remaining 51 cases, there were 202 decisions to extract (31 unanimous decision cases and 20 split decision cases). The clinicians cited a total of 469 reasons to support these decisions. Crowding was cited as the first reason in 49% of decisions to extract, followed by incisor protrusion (14%), need for PrOfile correction (8%), Class II severity (5%), and achievement of a stable result (5%). When all the reasons for extraction in each clinician's decision were considered as a group, crowding was cited in 73% of decisions, incisor protrusion in 35%, need for profile correction in 27%, Class II severity in 15% and posttreatment stability in 9%. Tooth size anomalies, midline deviations, reduced growth potential, severity of overjet, maintenance of existing profile, desire to close the bite, periodontal problems, and anticipation of poor cooperation accounted collectively for 12% of the first reasons and were mentioned in 54% of the decisions, implying that these considerations play a consequential, if secondary, role in the decision-making process. All other reasons taken together were mentioned in fewer than 20% of cases. In this sample at least, clinicians focused heavily on appearance-related factors that are qualitatively determinable by physical examination of the surface structures of the face and teeth. They appear to have made primary use of indicators available on study casts and facial photographs and relatively little use of information that is available only on cephalograms or that involves the application of specialized orthodontic theories. (AM J ORTHOD DENTOFAC ORTHOP 1996;109:393-402.)

I n a recent article,' we reported findings to the effect that the decision-making judgments of a group of skilled orthodontists showed stronger agree- ment than had been anticipated with respect to the question of whether to extract in the correction of Class I and Class II malocclusions. When the pretreat- ment records of 148 patients in a prospective clinical

Supported by NIDR-NIH grant no. DE08713. aprofessor Emeritus of Growth and Development, Radiology and Orthopedic Surgery, University of California, San Francisco; Clinical Professor, Orthodon- tics, University of Medicine and Dentistry of New Jersey, Newark, N.J. bHead, Clinical Trials Section, Biometric Research Branch, National Cancer Institute, Bethesda, Md. CProfessor and Chair, Division of Orthodontics, Department of Growth and Development, University of California, San Francisco. dFormerly Resident in Orthodontics, Division of Orthodontics, Department of Growth and Development, University of California, San Francisco; in the private practice of Orthodontics in Tacoma, Wash. Copyright © 1996 by the American Association of Orthodontists. 0889-5406/96/$5.00+ 0 8/1/70122

trial of conventional orthodontic treatment were exam- ined independently by five experienced clinicians, there was unanimous agreement among the clinicians on the appropriateness or inappropriateness of extrac- tion for two-thirds of the subjects (97/148 = 66%). Split decisions among the judges occurred in the remaining third of the cases and were considered to be objective evidence that those cases were of "border- line" status. Beating in mind that agreement does not assure correctness, we proceed in this article to exam- ine the clinicians' stated reasons for their decisions to extract. With data from a subset of subjects drawn at random from the previously reported sample, we now present findings addressing the following questions:

• What reasons did clinicians give most frequently for their decisions to extract?

• Were the reasons given for extracting for adoles- cents different from those given for adults?

393

394 Baumrind et aL American Journal of Orthodontics and Dentofacial Orthopedics April 1996

• Were the reasons g iven for extract ing in unani-

mous agreement cases different f rom those g iven

in "bo rde r l i ne" (i.e., split decision) cases?

• To what extent did different cl inicians tend to

give similar reasons for their decis ions to ex-

tract?

• In cases in which there was unanimous agree-

ment to extract, how wel l did the different clini-

cians agree on the reasons for extract ion on a

case by case basis?

• H o w frequent ly were the different reasons ci ted

in combina t ion with each other to support a

c l in ic ian ' s decis ion to extract?

MATERIALS AND METHODS

Data were available for 148 subjects (100 growing and 48 nongrowing), who had presented at the University of California-San Francisco Graduate Orthodontic Clinic re- questing treatment for correction of Class I or Class II malocclusions. Before defining the treatment plan for each subject, all records (including head films, dental x-ray film, study casts, facial and intraoral photographs, cephalometric tracings, and all written chart materials) had been examined by five orthodontic specialists drawn from a 14-member pool of clinical instructors. Each clinician (all were men) exam- ined the records for each patient without consultation with the other clinicians, recorded his treatment preference and the reasons for it on an individual Clinician's Case Analysis form (CCAF). A typical CCAF is shown in Fig. 1. These CCAFs provided us with five independent judgments as to whether extraction or nonextraction treatment was preferable for each individual subject. The 740 CCAFs (148 subjects times 5 CCAFs per subject) constitute the primary informa- tion source for this article and for the previously published first part of this study. ~

We had deliberately chosen not to restrict clinician responses to a prescribed set of choices and had instead solicited free-form statements "in approximate order of importance." This strategy produced a data set that was free from the impact of our own antecedent biases but that was relatively difficult to order and interpret. Given the nature of the data, it appeared wisest to conduct this first investigation in a descriptive/exploratory mode rather than by testing hypotheses that would necessarily have been ill formed. Consistent with this line of thinking, the sample was split into two subsamples with the aid of a table of random numbers. In the current study, we explore the properties of one subsample with the intention of developing from the data an intuitively reasonable set of testable hypotheses. In a subsequent study, we expect to test those hypotheses against the other subsample. Later, we will be able to test the generalizability of the surviving hypotheses against a third sample that has been generated by a different set of judges at the University of the Pacific.

The unit of analysis in this study is a single clinician's decision to extract in a single case, represented by a single CCAF. All reasons and comments on the 360 CCAFs for the 72 cases in the selected subsample were entered into a corn-

puter spreadsheet. This process resulted in a listing of 849 reasons, an average of 2.36 reasons per decision per judge (SD = 0.86). In 21 cases, all five clinicians chose to treat on a nonextraction basis; in 31 cases, the unanimous choice was extraction; and in the remaining 20 cases, the five clinicians split their decisions. Among the 51 cases in which choices for extraction had been made, there were 202 decisions to extract, supported by a total of 469 reasons (mean = 2.32).

On the basis of the inherent characteristics of the re- sponses and without establishing a priori groups, a single investigator (R.M.) distributed the 849 reasons into 41 cat- egories. The resulting categorization assignments were re- viewed and somewhat consolidated by a second investigator (S.B.), reducing the final number of categories to 14 groups of extraction reasons and 15 groups of nonextraction reasons. (Responses grouped within each category are treated as a single "reason.") This article focuses entirely on the data summarized from the 202 CCAFs in which clinicians de- cided to extract.

Because this study is primarily descriptive in nature, most of the statistical presentation is enumerative. However, with regard to the second and third questions listed in the Introduction, it was possible to make comparisons of dif- ferences between two groups of cases (i.e., between ado- lescents and adults or between unanimous and "borderline" cases). Because of the rather complicated structure of the data, the following method was used to identify differences greater than chance in the proportion of cases in which each particular reason was cited in the two groups of each comparison. First, for each of the 51 cases, the proportion of clinicians citing each particular reason was calculated. Second, a permutation t test 2 was used to test the null hypothesis that the underlying distribution of proportions for a particular reason was the same for the two groups. All p values reported are two-sided and unadjusted for the multiple comparisons being made. These tests do account for the fact that the reasons stated for each given case by different clinicians can be expected to be correlated, due to the specific characteristics of that particular case. They do not, however, make use of the information about which clinicians or how many clinicians opted for extraction in each individual case.

RESULTS

The findings of this study are organized as tabu-

lated responses to the six quest ions cited at the begin-

ning o f this article. A separate table was prepared in

answer to each quest ion but to save space, only

abbreviated vers ions of the data are printed here. Ful ler

tabulations are avai lable in other publ icat ions 3'4 or on

request. With respect to each question, the data for the

13 mos t p rominen t categories of reasons for extract ion

were tallied. These categories are l isted in descending

order o f inc idence in Table I, in which all other reasons

g iven to support decis ions to extract are grouped in a

fourteenth ca tegory des ignated "Othe r . " Figs. 2, 3, and

4 show the images presented to the cl inicians for three

representat ive patients for w h o m different decis ions

American Journal of Orthodontics and Dentoj~zcial Orthopedics B a u m r i n d et al. 3 9 5 Volume 109, No. 4

Patient Name Patient # IL~_~_~% Date ~__.l~g'/-3J [ ] Adult ~ ] Adolescent (Youth_) \ Resident Name Initial Assigned Faculty ILL, --

Form 02.2 8/27t90 u

Department of Growth and Development Graduate Orthodontic Clinic - Prospective Orthodontic Study

DE#08713

C L I N I C I A N ' S C A S E A N A L Y S I S F O R M m l m m m m ~ a m m m u N B m m l = u m m m m m n m = n m m m m * a m m m * m m m m

Clinician's Name _ ~

Please review the record for this patient and answer the following questions. Please do not discuss this patient with the othe[ case evatuators until all evaluators have completed their independent reviews.

2.

The patient's Angle classification patient is:

[ ] classl [ ] c~m 12/ class,1 [ ] c ~ [ ] Class 11.2

I believe this patient would be best treated with a plan that: J'x: # / ~ ,v',~,,,/~ ,'~

IncltJdes extractions other than third molars.

Please indicate probable preferred extraction pattern:

D e s e rTe I - ~ Other (Indicate)

[ ] Does not include extractions (except possitby third rn~lars).

P~ease estimate the likelihood that extraction may be indicated later.

[ ] Highly Improbable

[ ] Possible but not probable

[ ] Quite p~ssiNe (more than 3 chances in 10)

3. Treatment for this patient:

[ ] Should inlcude orthognathic surgery. [2~ Should not INcude orthognathic surgery.

6. My decision to extract or not extract is based on the following considerations in approximate order of importance:

l~/,q~T~/~" - /~ ,~'l,~ ,r,Q ~ ,W~ ca/ ,~c, ,,4~ ,'/,6 ~,,~ .{ ~ - ~ ,~,z a~-.

b) /V'o f~o-a~O~

e) ,'¢.~. , ~ ¢ . ~ , a / k - , x ~ , , - , ¢

o~

(Please seal this form Into the accompanying envelope before returning It to the resident.)

Fig. 1, Representative clinician's case analysis form.

were made. The clinician decisions for these three cases are listed in full in Table II.

Question 1: What reasons were most frequently given for deciding to extract?

The distribution of the 469 reasons given for the 202 extraction decisions for all 51 subjects for whom such recommendations were tabulated. Numerical and percentage data were listed for both first replies and all replies.

Among first replies, crowding was cited on almost half of all CCAFs (49%), followed by incisor protru-

sion (14%), desire to improve profile appearance (8%),

and concern over Class II severi ty or anteroposter ior discrepancy (5%). Concern f o r pos t t rea tment stabili ty was cited as the first reply on 5% of CCAFs all the CCAFs citing stability were contributed by a single clinician). Taken together, the first five reasons ac- counted for 84% of the first replies. Beyond the five most commonly cited reasons, no single reason was cited as a first reply on more than 2% of the CCAFs.

When "all replies" were considered, crowding was found to have been cited in support of 146 of the 202 of decisions favoring extraction (i.e., on 72% of the CCAFs), incisor protrusion in 35%, profile improve- ment in 27%, and anteroposter ior d iscrepancy or Class

396 Baumr ind et al. American Journal of Orthodontics and Dentofacial Orthopedics April 1996

Table I. Reasons most frequently cited by clinicians for deciding to extract

Reason no. Reason

Number of CCAFs*

First replies All replies

1 Crowding 98 2 Incisor protrusion 29 3 To improve the profile 17 4 Class lI severity/A-P discrepancy 10 5 Stability of outcome l 1 6 Tooth size or shape anomaly 5 7 Midline deviation 3 8 Reduced or no growth potential 4 9 Overjet 4

10 To maintain the profile 4 11 To close the bite 2 12 Periodontal problem 2 13 Poor cooperation anticipated 3 14 Other 9

Totals 201 t

Percentages of CCAFs

First replies I All replies

146 71 55 29 19 18 18 17 15 12 15 12 4

38

469

49 72 14 35 8 27 5 15 5 9 2 9 1 9 2 8 2 7 2 6 1 7 1 6 I 2 4 19

97 231

*CCAF -- Clinician case analysis form. Total CCAFs = 202 Total cases = 51. ?One clinician did not specify any reason(s) for one decision.

II severity in 15%. No other reason was cited on more than 9% of CCAFs.

It seems clear that the concern of the clinicians was focused heavily on the first four reasons and, in particular, on crowding.

Question 2: Were the reasons given for extracting for adolescents different from those given for adults?

There were 122 CCAFs from 33 adolescent sub- jects and 80 CCAFs from 18 adult subjects. The pattern of "first replies" revealed no evidence of statistically significant differences between adolescents and adults. When "all replies" were examined, mar- ginally significant differences were noted for crowding (p < 0.05). There were also suggestions of possible differences (that is to say p values between 0.05 and 0.10) for Class H severity and maintenance of profile among "first replies" and for Class II severity and stability among "all replies."

The most striking finding, with respect to this question, was that there was little difference between the distribution of reasons given for extraction in adolescents and the distribution of reasons given for extraction in adults. Particularly surprising was the failure to find statistically significant differences with regard to reason no. 9, reduced or no growth potential.

Question 3: Were the reasons for extracting in unanimous agreement cases different from those in "borderline" cases?

The data set included 155 CCAFs from 31 unani- mous agreement subjects and 47 CCAFs from 20 split

decision borderline subjects. Among the "first replies," a strongly significant difference between groups with respect to crowding (p < 0.001l). On the basis of this finding, we may infer with confidence that crowding played a more prominent role in decisions to extract in unanimous agreement cases than it did in borderline cases. The data for first replies also yield evidence of the possibility that midline deviations were a more prominent factor in borderline cases than they were in unanimous cases. No additional information on signif- icant differences between the borderline and the unani- mous agreement cases was found when the pooled data for "all replies" was considered.

Question 4: To what extent did different clinicians tend to give different reasons for their decisions to extract?

The intent of this question was to find out whether different clinicians based their decisions to extract on the same or on different criteria. For the purpose of answering this question, the three clinicians in the 14-member panel who made fewer than nine extraction decisions were dropped from consideration. Among the remaining 11 clinicians, crowding was the reason most commonly cited by 10, ranging between 64% and 86% of cases per clinician. For each of these 10 clinicians, either incisor protrusion, profile improvement, or Class II severity was the second most commonly cited reason for the decision to extract.

Only one clinician, (clinician 11), failed to list crowding as a reason for extraction in at least half of his decisions to extract. Interestingly, this clinician was the only one who cited concerns about stability as a

American Journal o/'Orthodontics and Dentqlhcial Orthopedics Baumrind et al, 397 Volume 109, No. 4

Fig. 2. Subset drawn from images presented to five clinicians for use in making their extrac- tion/nonextraction decision for subject 63. Decisions of five judges may be seen in Table II. A, Facial photographs. B, Intraoral photographs. C, Cast molds. D, Radiographs.

reason for extraction. Indeed, clinician 11 cited stabil- ity more frequently than any other reason, listing it in 19 (86%) of his 22 extraction decisions. (It is of some interest to note that despite these apparent dissimilari- ties in criteria, clinician l l ' s decisions for and against extraction concorded well with those of his peers, indeed at a slightly better than average rate.)

Another surprising finding from the responses to this question is that only 6 of the I l clinicians indicated that the issue of residual growth potential had played a role in their extraction decisions. Indeed, only one of

these six (clinician 8) noted growth-related issues in as many as a quarter of the cases he evaluated.

Quest ion 5: In cases in which there was unanimous agreement to extract, how well did the

different clinicians agree on the reasons for extraction on a case by case basis?

Here we consider agreement on among first replies separately from agreement on all replies. Crowding was cited first by all five clinicians in five cases and no other reason was cited first by all judges in any case.

398 Baumrind et al. American Journal of Orthodontic:s" and Dentofacial Orthopedics April 1996

Fig. 3. Subset drawn from images presented to five clinicians for use in making their extrac- tion/nonextraction decision for subject 120. Decisions of five judges may be seen in Table li. A, Facial photographs. B, Intraoral photographs. C, Cast molds. D, Radiographs.

Four of the five clinicians gave the same first reply in

nine additional cases (citing crowding in seven cases, incisor protrusion in one, and Class I1 severity in one). Three of the five clinicians gave the same first reply in a total of nine additional cases (citing crowding in six, incisor protrusion in one, profile improvement in one, and anticipated poor cooperation in one). Thus it can be said that a majori ty of participating cl inicians

cited the same reason first in 22 of the 31 cases. In

addition, two of the five clinicians cited the same reason first in six cases (crowding in three cases and incisor protrusion in three cases). In all but three cases, crowding was cited as a first reply by at least one clinician. In only one case did more than one clinician give a first reply that was not one of the four most frequently cited reasons. In only four cases did any

American Journal of Orthodotltics and Dentqt~tcial Orthopedics B a u m r i n d et al. 399 Volume 109, No. 4

Fig. 4, Subset drawn from images presented to five clinicians for use in making their extrac- tion/nonextraction decision for subject 150. Decisions of five judges may be seen in Table II. A, Facial photographs. B, Intraoral photographs. C, Cast molds. D, Radiographs.

clinician designate a reason in the Other category as his first reply.

When all replies on each CCAF were considered, the number of clinicians who cited the same reason for their decisions to extract was seen to increase. Crowd- ing remained the reason for which the largest number

of unanimous or near unanimous agreements among clinicians was found. (All five clinicians cited crowd-

ing in 10 cases and four of the five clinicians cited crowding in an additional 14 cases . ) lncisorprot rus ion is also cited unanimously in three cases and by four of the five clinicians in four additional cases. However, beyond these two most frequently cited reasons, agree- ment among all clinicians was not seen for any reason in any case, and agreement among four of the five

clinicians was observed in only 10% of the cases in the

400 Baumrind et aL American Journal of Orthodontics and Dentofacial Orthopedics April I996

T a b l e II. Reasons g iven for judges ' decis ions to extract or not to extract in three specific representat ive cases

I Judge no. [ Decision

Case 63. Growing female. Unanimous agreement n o t to extract 5 NX

8 NX

10 NX

11 NX

13 NX

Case 120. Nongrowing female. Unanimous agreement to extract 3 All four first premolars 6 All four first premolars

7 All four first premolars

11 Upper second premolars, lower first premolars

12 All four first premolars

Case 150. Nongrowing male. Disagreement (3 : 2 split decision) 2 All four first premolars

5 All four first premolars

7 NX

9 NX

13 NX

Reasons

1 Minimal crowding 2 Root length 1 Root length 2 Open bite 1 Class II is mild 20verjet is moderate 1 Minimal crowding 2 Profile 3 Reduced anterior CR ratio 1 Adequate arch length 2 Anterior roots are very short

1 Crowding 1 Moderate crowding 2 Bimax protrusive 3 Lip fullness 1 Protrusion 2 Arch length problem 1 Stability 2 For better facial balance 1 Arch length deficiency 2 Protrusive upper and lower dentition

1 Profile 2 Crowding 1 Amount of crowding 2 Vertical skeletal pattern with open bite 3 Age (growth potential) 1 Adequate arch length 2 Straight profile 1 Adequate length 2,Narrow maxillary arch 1 Lower arch length discrepancy is slight 2 Straight profile

NX, not to extract. These answers are transcribed without modification from the answers given to the sixth question on the CCAF shown in Fig. 1.

sample (i.e., on Class II severity in two cases and on

the anticipation o f p o o r cooperation in one case).

As ide f rom the four leading reasons, there were only

three addit ional reasons for which as many as three

cl inicians agreed within a single case.

Examina t ion of the findings f rom the al ternat ive

perspect ive o f nonagreement be tween judges reveals

that on 92 of the 155 individual C C A F s (60%), a

cl inician specif ied at least one reason that was not

specified by any of the four other cl inicians evaluat ing

the same case.

Finally, looking at the section B findings on a

casewise basis, one notes that crowding was cited by at

least one cl inician in all but 3 of the 31 cases and

profile improvement was cited by at least one cl inician

in all but four cases. Each of the other reasons went

unci ted in at least 13 o f the 31 cases.

Question 6: How frequently were different reasons cited in combination with each other to support a clinician's decision to extract? (i.e., When one reason was cited as a basis for extraction, how often was each other reason also specified?)

To answer this question, we tal l ied the number o f

t imes each pair of reasons was listed together as the

basis for a c l in ic ian ' s decis ion to extract in a single

case. I f the combinat ions among reasons occurred on a

purely r andom basis, then we would expec t the inci-

dence o f each combina t ion o f reasons to be propor-

t ional to the product o f the incidences o f the two

individual reasons that contr ibute to it. For example ,

because crowding was cited on 146 of the 202 C C A F s

(72%) and profile improvement was ci ted on 55 o f the

202 C C A F s (27%), we would expect by chance to see

the two cited in combina t ion on 72% x 27% of the 202

American Journal of Orthodontics and Dentofacial Orthopedics Baumrind et al. 401 Volume 109, No. 4

CCAFs (which is to say, on 39 of them). The actual observed incidence of this pairing of reasons was 33.

Viewed from this perspective, the only pairings in this table that departed from chance expectation were a dramatic association between profile improvement and stability (which results from the responses of a single clinician, clinician 11), and a much less strong asso- ciation between tooth size~shape anomaly and mainte- nance of profile. Given the large number of compari- sons (14 x 14 = 196), the detection this small number of apparently nonrandom events means that there is no substantial evidence of associations stronger than chance among the different reasons.

DISCUSSION

In designing this study, we sought to keep the conditions under which the clinicians were asked to make their decisions as close as possible to the usual conditions of clinical practice. Thus all records were provided to the clinicians simultaneously rather than piecemeal as in the case of another recent study. 5 Similarly, care was taken to secure answers in the clinicians' own words rather than in the form of more constraining checklists. Examining the findings, one is struck by the frequency with which the three leading reasons for extraction were specified. Crowding was cited in 72% of all individual clinician decisions to extract and listed first in 49%. Incisor protrusion was listed first in 14% of all decisions and was mentioned in 35%. Profile improvement was mentioned in 27% of decisions, although it was listed first in only 8%. Either crowding or incisor protrusion was mentioned in 84% of decisions (169 of 202 CCAFs); either crowding or profile improvement was mentioned in 83% of deci- sions (168 of 202 CCAFs). One of the three leading reasons was mentioned first in 71% of all decisions to extract (98 + 29 + 17 CCAFs) and at least one of the three was mentioned in 91% of all decisions (183 CCAFs). It is interesting to note that these three measures also emerged as key criteria leading to the adoption of an extraction strategy in the studies of Paquette, Johnston et al. 6 and that they appeared at the top of the list of extraction predictors in our own preliminary studies. 7'8

On a case by case basis, the greatest agreement among clinicians was again encountered with respect to crowding. Among the 31 cases in which there was a unanimous decision to extract, all five clinicians iden- tified crowding as one of the reasons for their decision in 10 cases and at least four of the five clinicians cited crowding in 24 cases. In 90% of the unanimous extraction cases, crowding was cited by at least one clinician. Incisor protrusion also evoked some unani- mity of decision-making, being agreed on unanimously

in three cases and by four out of five clinicians in four additional cases. Among the remaining reasons, how- ever, the incidence of agreement among clinicians fell dramatically. Aside from crowding and incisor protru- sion, agreement on a single reason by as many as four clinicians was found in only three cases (two for Class H severity and one for anticipated poor cooperation). Even agreement among as many as three clinicians was found for relatively few additional reasons (four cases for profile improvement, two for Class II severity, and one each for tooth size anomaly, midline deviation, and anticipation of reduced growth potential). It is, of course, possible that different clinicians used different wordings to identify similar phenomena (and vice versa), but insufficient data were available to test the extent to which such confounding had occurred.

It seems noteworthy that, in this sample at least, the clinicians focused heavily on appearance-related fac- tors that are qualitatively determinable by physical examination of the visually apparent surfaces of the face and teeth. This is to say that considerable use was made of indicators available on study casts and facial photographs and relatively little use was made of information which is available only on cephalograms or which involves the application of specialized ortho- dontic theories. Only a few of the clinician-specified reasons involved conceptual issues or other parameters not directly observable by the clinicians at the time of intake examination. (These findings are in general agreement with those of Vig and others. 5) Among conceptual and theory-based issues, one may list sta- bility of outcome (mentioned in 9% of decisions but by only a single clinician), reduced or no growth potential (mentioned on 8% of decisions), to close the bite (7%), maintenance of profile (6%), and anticipation of poor cooperation (mentioned in only one case).

CONCLUSION

In evaluating these findings, it should be kept in mind that this study dealt only with how clinicians decide whether to extract or not and did not address such other crucial questions as how they decide whether and when to treat, how they develop and implement detailed plans of treatment, and how they evaluate changes dur- ing and after treatment. It would therefore be inappro- priate to conclude from these findings that cephalo- grams and other diagnostic aids are without a major role in orthodontic decision-making.

Three additional caveats should be kept in mind in evaluating the findings of this study. First, the manner in which we established the categories into which the clinician's free-form answers were distributed was by no means the only possible one. Other investigators may well have chosen different categories for grouping

402 Baumrind et al. American Journal of Orthodontics and Dentofacial Orthopedics April 1996

these data. Second, it should be r emembered that the

data are drawn f rom the analysis o f a single subsample

and that the degree o f genera l iza t ion that is appropriate

f rom that subsample is not yet ent i rely clear. Interested

invest igators who wish to at tempt alterative order ings

o f the raw data are invi ted to contact us. Third,

a l though this study provides useful informat ion on

current c l inician attitudes toward extraction, it is well-

known that such attitudes are known to be subject to

secular trends through time. 9

Finally, it is appropriate to note again that agree-

ment among cl inicians does not assure that the agreed

on posi t ion is the correct one. The correctness o f the

cl inician decis ions reported in this study wil l not be

defini t ively de terminable until wel l after t reatment has

been completed.

REFERENCES

1. Baumrind S, et al. The decision to extract: Part I--Inter-clinician agreement. AM J ORTHOD DEr~TOFAC ORTHOP 1996;109:297-309.

2. CYTEL StatXact users manual. Cambridge: CYTEL Software Corporation, 1991.

3. Baumrind S. Clinical studies in orthodontics: a view from Cali- fornia. Harvard Soc Adv Orthod, [In press.]

4. Banmrind S. The decision to extract: preliminary findings from a prospective clinical trial. In: Orthodontic treatment: outcome and effectiveness. Minneapolis: University of Michigan Press, 1995.

5. Han U, et al. Consistency of orthodontic treatment decisions relative to diagnostic records. AM J ORTHOD DENTOFAC ORTHOP 1991;100:212-9.

6. Paquette DE, Beattie JR, Johnston LE. A long-term comparison of nonextraction and premolar extraction edgewise therapy in "bor- derline" Class II patients. AM J ORTHOI) DENTOFAC ORTHOP 1992; 102:1214.

7. Portalupe RH. An objective screening instrument for the adult borderline crowded group. [MSD Thesis.] Stockton, California: University of the Pacific, School of Dentistry, 1989.

8. Gray BL. Clinical considerations in extraction decisions. [MSD Thesis.] Stockton, California: University of the Pacific, School of Dentistry, 1991.

9. Proffitt WR. Forty-year review of extraction frequencies at a university orthodontic trial. Angle Orthod 1994;64:407-13.

Reprint requests to: Dr. Sheldon Baumrind 1525 Walnut St. Berkeley, CA 94707-1512