Contribution of pretreatment radiographs to orthodontists’ decision making Kathryn A. Atchison, DDS, MPH,” Larry S. Luke, DDS, MS,b and Stuart C. White, DDS. PhD,c Los Angeles, Calif. UNIVERSITY OF CALIFORNIA, LOS ANGELES, SCHOOL OF DENTISTRY A study was conducted to determine the amount of diagnostic and treatment planning information gained by orthodontists when pretreatment radiographs are added to a set of orthodontic records. Thirty-nine orthodontists evaluated six test cases and formulated a diagnosis and treatment plan. Information was collected about the participants’ certainty with their diagnoses and treatment plans, the impact of the radiographs, the number and type of radiographs that were selected, and the difficulty of each case. Results showed that orthodontists were approximately 75% confident of their diagnosis before reviewing any radiograph. There were 741 radiographs ordered, of which 192 produced changes to the diagnostic process. The lateral cephalometric radiograph was the most productive. Panoramic and full-mouth series were productive but provided largely duplicative information. (ORAL SURC ORAL MED ORAL PATHOL 1991;71:238-45)
B
efore initiating orthodontic treatment, an orthodontist typically performs a medical and dental history and a comprehensive clinical examination. Additional orthodontic records assembledfor patients include photographs, study models, and a radiographic examination. The primary purpose of the radiographic examination is to provide additional information that may not be evident clinically. A review of orthodontic textbooks revealed that most texts do not make recommendations for a standard radiographic survey; rather, they describe films that may be useful in diagnosis and treatment planning.lV6The most frequently recommendedviews are full-mouth periapical and bitewing radiographs (FMX) and/or a panoramic radiograph and a lateral cephalometric (LC) radiograph. Other projections less frequently suggestedincluded the 45degree LC radiograph, occlusal radiograph, hand-wrist radiograph, lateral jaw radiograph, posterior-anterior cephalometric (PAC) radiograph, and temporomandibular (TMJ) projections. Recently published American Association of Orthodontists guidelines’ recommend that an LC and a panoramic or complete intraoral radiographs should be used for orthodontic aAssistant Professor, Section of Public Health Dentistry. bCIinical Professor, Sections of Pediatric Dentistry and Orthodontics. cProfessor,Section of Oral Radiology. 7/M/20721 238
diagnosis and treatment planning of comprehensive cases. A survey of practicing orthodontists confirmed that these recommendations are generally followed. A questionnaire distributed to dental schools and individual orthodontic practitioners by Atchison* in 1985 reported that more than 90% of the orthodontists responded that they order an LC and panoramic radiograph for their patients with permanent dentition. Approximately 70% reported ordering them on patients in the primary and early mixed dentition. The remainder of the radiographs were ordered 40% of the time or less for patients. The results further showed that the number of pretreatment radiographs ordered dependedon the orthodontist’s type of practice (educator vs private practitioner) and age of the patient. Educators reported ordering 1.4 times as many radiographs as private practitioners. More orthodontists reported ordering radiographs for patients older than 10 years of age than for younger patients. Nieberg and Sinclair9 found similar results in a survey of predoctoral orthodontic programs. They report that the majority of the schools report requesting FMX, a panoramic, and an LC radiograph as part of the diagnostic records for some or all their patient cases. It is not clear, however, how much radiographs contribute to the orthodontist’s diagnostic and treatment planning process.Recent concern expressedby the public as well as by clinicians about accruing ion-
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Table I. Patient characteristics for the six test cases
AgeWI Case
sex
A B C D E F
12/M 13/M 19/M 18/M 26/F
8/F
Skeletal classification
I 11 II I I II
Midline deviation
Posterior crossbites
Lower face height
Molar crowding
No Yes No No Yes
None None None Bilateral Bilateral Unilateral
Normal Long Short Long Normal Normal
Yes Yes No Yes No No
izing radiation has spurred an evaluation of diagnostic radiation use to determine the contribution of radiographs to the clinician’s management of patients. The intent of such evaluations is to examine the efficacy of radiographs, alone and in combinations, in terms of their contribution to diagnosis and treatment planning.‘O The purpose of this study was to determine quantitatively the amount of diagnostic and treatment planning information gained by orthodontists when radiographs are added to a set of orthodontic records and a previously charted medical and dental history and oral examination. MATERIAL AND METHODS Overview
In the present study, orthodontists were shown six casesand asked to diagnose (enumerate the problems presented in) each caseand describe a treatment plan (solution for problems). Each orthodontist then estimated the gain in confidence resulting from examination of successive,selectedradiographs until they felt confident they had all diagnostic information they needed to proceed with patient care. Study cases
The study models and records of six patients seen for orthodontic consultation at the University of California-Los Angeles orthodontic clinic were selected and duplicated (maintaining the patients’ confidentiality). The cases,as seenin Table I, were chosen to represent common malocclusion problems treated by orthodontists. These included two casesof asymmetry, three molar crowding, three posterior crossbites,and one anterior open bite case.The initial records consisted of a medical and dental history, study models, intraoral and extraoral photographs, a charting of the patient’s oral examination, and the radiographs chosen by the supervising faculty orthodontist. The minimum set of radiographs consisted of an FMX, a panoramic, maxillary and mandibular occlusals, LC and PAC views, a carpal index (CI), and lateral TMJ or transcranial tomograms. In addi-
tion, several caseshad a submental vertex radiograph present, which was duplicated and included with the minimum set. Participants
A letter was sent to members of the Pacific Coast Society of Orthodontists who resided in the west Los Angeles and the near San Fernando Valley. Orthodontists were asked to return a form with their telephone number if they were willing to participate in a research project dealing with the radiographs usedfor orthodontic diagnosis. A letter was also sent to the faculty of two orthodontic programs. The authors telephoned 40 responding orthodontists and explained that participation involved a 2-hour interview during which the participant would evaluate patient cases. Orthodontists were assured that we were not testing the accuracy of their diagnosis or treatment plan but, rather, were evaluating the specific information orthodontists use to formulate their diagnosis and treatment plans. Interview
format
A standardized interview schedule was developed and pilot tested on four faculty orthodontists, and appropriate refinements were made. For each case the participant was presented first with the study models, intraoral and extraoral photographs, and the charting of the oral examination. They were asked to formulate a diagnosis and describe it to the interviewer. They were then asked to estimate their degree of certainty that the diagnosis was accurate and complete. This was recorded on a percent confidence visual analog scale ranging from 0% confidence (basically a pure guess) to 100% confidence (absolute certainty) that the diagnosis was correct. This process was repeated for the treatment plan. The interviewer then informed the participant that radiographs could be requested individually if needed to complete the diagnosis or treatment plan. The Ricketts, Downs, Steiner, Wits, Harvold, and Sassouni analyses were presented when an LC radiograph was requested. Some participants did their own analysis. The FMX
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was given whenever a portion of it was requested, although the part specified was recorded. Each participant was asked to describe the reasons for ordering each radiograph. After examining the radiograph, the orthodontist summarized the diagnostic information gleaned from the radiograph and noted whether it caused a change, confirmation, or enhancement to the diagnosis. The participant’s new certainty with the diagnosis was recorded. He or she was then asked whether the radiograph caused any change, confirmation, or enhancement to the treatment plan and to estimate his or her new certainty with the treatment plan. The processwas repeated for each additional radiograph the participant requested until the participant felt comfortable that all the information about the patient, short of seeing the patient personally, had been gathered. At this point the participant’s final certainty with both diagnosis and treatment plan was recorded. He or she was then asked to estimate the difficulty of the case and describe any additional records that would be needed for this patient. This processwas repeated for the remaining five cases.One case,selected by the authors as an easily diagnosedcase,was always presentedfirst and the order of the remaining five cases was randomized to prevent a possible fatigue effect. Data analysis
Analysis was conducted on each patient case individually (six groups). In addition, all caseswere combined. The information sought from each case included (1) the participant’s level of initial and final certainty with the diagnosis and treatment plan, (2) the impact of the radiographs on diagnosis and the treatment plan, (3) the number, type, and order in which radiographs were selected, (4) the difficulty of each case, (5) the information sought from each radiograph, and (6) the information provided by the radiographs. An impact was defined as either a change or confirmation to the diagnosis or treatment plan. The difficulty of each casewas assessedby the participant, at completion of the caseas a 1 for an easycase, 2 for a typical case, and 3 for a difficult case. A diffculty index was calculated for each patient caseby calculating the mean number assessedper case. Four separate lines of analysis were used to evaluate the contribution of the radiographs to the diagnosis and treatment plan. The first analysis assessedthe change in the participant’s confidence or certainty as clinical and radiographic information about the patient was received. We expected that additional information should act to increase the participants’ certainty with their diagnoses and treatment plans until they would declare themselvessatisfied with the information and ready, hypothetically, to treat the patient. Distributions of individual participants’ di-
agnostic and treatment certainty were plotted by case and in total. Analysis of variance with repeated measures was used to test whether participants’ initial diagnostic certainty (before reviewing any radiographs) varied by case,and whether the difficulty of the case was reflected in the participants’ certainty. This was repeated for the treatment certainty. Next, the number of radiographs ordered and which individual radiographs were ordered for each caseby a participant were evaluated. A greater number of radiographs suggestedto us a greater requirement for diagnostic information to analyze the case. Further, examinations that are requested more frequently would reasonably be expectedto contribute to the diagnostic process. Descriptive statistics were calculated by case, by participant, and in total. A never-use indicator was also derived to assesshow widespread the use of individual radiographic examinations are among the orthodontists studied. This indicator was computed by tabulating the percentage of participants who never ordered a particular projection for any of the six test cases.Analysis of variance with repeated measures, with the number of radiographs ordered as the dependent variable and the patient case and the orthodontist as controlling variables, was conducted. Analysis of covariance, with the difficulty index as the covariate, was also conducted. To determine the degree to which orthodontists agree on which radiographs to order for patients, a homogeneity value was developed and calculated for each radiograph. The homogeneity value considers the degree of agreement among orthodontists regarding whether to order a particular radiograph for each case.Scorescan range from 0 to 1. The optimal score of 1 is reached when all orthodontists agree either in favor of ordering the radiograph or not, whereas a scoreof 0 indicates that half the orthodontists ordered the film and half did not. A score of lessthan 0.7 signifies substantial disagreement among the orthodontists on when the radiograph is indicated. The equation for the homogeneity value is
H=
[
2, c=
x1
W)l
1 /
(42)
where H = homogeneity value, x = the number of participants who ordered a radiograph for the specific case, n = the number of participants, and i = the number of cases. Descriptive statistics were also used to evaluate the impact of individual radiographs. The percentage of radiographs that caused a change in either the diagnosis or treatment plan was determined, to evaluate the efficacy or productivity of each type of film. To test
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Orthodontist % Certainty
24 1
.O- Treatment
_Clln. Rev.
5
;
6
Number radiographs requested
Fig. 1. Distribution represents certainty of average practitioner regarding diagnosis and treatment plan both before and after reviewing radiographs. Standard deviation is shown in parentheses (n = 39).
Of the 40 orthodontists who began the interview, 39 completed all six cases. The final participant had completed three casesat the end of 2 hours and did not wish to donate further time to the project. The data analysis is based on only the 39 complete sets of data.
the radiographic examination. This group reported a higher mean certainty before reviewing any radiographs. Difficulty scorescould range from 1 for an easycase to 3 for a difficult case.The mean difficulty rating assigned to each case by the orthodontists and the certainties for the various casesare compared in Table II. The initial diagnostic certainty after clinical review but before reviewing any radiographs varied among the six caseswhen examined using analysis of variance. Case A, with a high of 80% certainty, was significantly different from caseD, which had a mean certainty of 69%. The use of difficulty rating as a covariate did not explain this difference. The average final diagnostic certainty, based on all diagnostic information present, was approximately 88%. Certainty values for treatment plans were consistently less than for diagnosis, but in only two cases,D and E, was the difference between treatment plan and diagnosis significant at the 0.05 (Ylevel.
Change in participants’
Number and type of radiographs
for a difference in the proportion of changes made to diagnosis versus treatment plan, McNemar’s test of symmetry’ ’ was used. Finally, the sequenceof ordering the radiographic examinations was examined to seewhether sequence affected the outcome of the casein terms of certainty or number of films ordered. To do that, we examined how many additional radiographs an orthodontist ordered after the first radiograph, when the first radiograph was an LC, a panoramic, or an FMX. The increasein certainty after the first radiograph was also examined. RESULTS
certainty
The certainty distribution for each test case was examined. Finding a similar trajectory for each case, the caseswere grouped together for easeof presentation. Fig. 1 shows that the participants were on average 75% certain of their diagnosis and 70% certain of their treatment plan before reviewing any radiographs. Further, participants gained the majority of their confidence on the basis of information observed on the first two or three radiographs. When gains in confidence for individual participants were examined, two unique distributions for the participants were found. Most of the participants followed the trajectory projected in Fig. 1. Approximately 30% of the participants (ranging from 6 to 14 participants, depending on the case), however, never changed their certainty as a result of a radiograph. Thus for these orthodontists the certainty with the diagnosis and treatment expressed after examining the initial records represented the same certainty at the end of
ordered
Participants ordered a total of 741 radiographs to complete diagnoses and treatment plans for the six cases. The total number of radiographs ordered by participants for the casesranged from 12 to 3 1, or an average of 3.2 radiographic examinations per case. The number of examinations ordered varied significantly only between cases D and F (Table II). The fewest radiographs were ordered for casesA and F. The difficulty of the casedid not explain the variation between casesin terms of the number of radiographs requested by the participant. As seenin Table III, the LC was ordered most frequently, followed by the panoramic and the FMX. Other radiographic examinations were ordered much lessfrequently (one fourth or less of the available opportunities). Another indication of thevariation in the ordering behavior is how many orthodontists never use a particular radiograph for any patient. The never-use indicator in Table III shows that the LC, pan-
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Table II. Description of case difficulty, number of radiographs ordered, and initial and final certainty with diagnosis and treatment plan -
Case
Mean dificulty rating
A B C D E F *Significant
1.6 2.6 2.8 2.8 2.7 2.3
% diagnostic certainty (mean k SD) Initial 80* 76 76 69* 75 75
+ rt k k * +
% treatment plan certainty (mean k SD)
Final
17.4 19.2 18.3 25.4 19.3 22.9
91 88 86 85 87 88
+ + k + + 2
Initial
14.4 15.6 17.6 15.6 15.8 16.8
16 69 70 61 65 68
Final
+ 20.6 t 24.1 -+ 19.2 + 25.3 +- 23.8 r 22.9
91 84 83 82 81 86
k 14.6 k 19.7 f 17.8 + 18.2 + 18.5 -+ 15.7
Mean No. of radiographs
No. of diagnosis changes
I
3.0 3.4 3.1 3.5* 3.2 3.0*
25
10 20 29 29
No. of treatmeni changes 18 34 18 35
I5 28
differences among cases; p < 0.05.
Table Ill. Number of radiographs ordered and resulting changes produced in participant’s diagnosis and treatment plan Radiographs
No. ordered
LC Panoramic FMX PAC TMJ Occlusal CI Submental vertex Total *Two additional
230
178 170 59 58 28 13 3
741*
No. of changes
No. producing ~1 change
Diagnostic
71 59 35 13
10 1 1
Treatment
Total
46 32 26 7 8
55 50 26 8 6
101
0 0
I 1 1 148
1 1
2
2
192
120
82 52 15 14
2
Never use (%)
0 10 3 44 49 12 82 92
Homogeneity 0.97 0.52 0.45 0.50 0.50 0.76 0.89 0.97
268
radiographs were ordered, a lateral jaw and a serial lateral head plate, which were not available for examining.
oramic, and the FMX were ordered by 90% or more of the orthodontists. Slightly less than half the participants never ordered PAC or TMJ projections. The remaining three radiographs were ordered by 30% or fewer of the participants. Seventeenof the 39 participants (44%) never ordered a PAC, and 32 participants (82%) never ordered a CI. The homogeneity value quantifies the amount of agreement among the participants on when each specific radiograph was indicated for an individual case. Table III shows that the LC and the CI both showed good agreement among participants as to when they are indicated. The LC wasordered almost universally, and the CI was rarely ordered. Radiographs such as the panoramic, FMX, PAC, and TMJ showed poor agreement as to when they are indicated. For the panoramic and FMX, one was always ordered, but the participants did not agree on which to order. To test whether the patient case or the individual orthodontist was more important in determining how many total radiographs were ordered for the cases,we compared the variability in number of radiographs ordered among orthodontists with the variability of radiographs for the cases. The mean number of radiographs ordered by the participants ranged from
2.0 to 5.7 radiographs per case.The comparable range for the mean number of radiographs per test casewas 3.0 to 3.5 radiographs. Thevariation (as measured by the standard deviation) associatedwith the individual orthodontist was approximately 1.6 times greater than that associated with the patients case. Because an LC examination and either a panoramic or an FMX were ordered nearly universally, a separate analysis was performed on the ordering of lessfrequently ordered radiographs, the supplemental radiographs. A mean of 0.7 supplementary radiographs were ordered per patient. We compared the variability among orthodontists and patient casesfor the number of supplemental radiographs. The mean number of supplementary films ranged from 0 to 2.5 radiographs for the participants. For the test casesit varied from 0.4 to 0.9 radiographs. The proportion of variation (as measuredby the standard deviation) associated with the orthodontist was appruximately 1.2 times greater than that of the patient case. Thus for both total number of radiographs and the supplementary radiographs the individ~lorthodontistwas more important than the patient case in explaining the variance associated with the number of radiographs ordered during the diagnostic process.
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Table IV. Use of panoramic and FMX examinations for a single patient Times both PAN and Fh4X used together
Patient
Times both PAN and FMX changed diagnosis or treatment when ordered together
7 (9) 13 (22) 7 (9) 7 (13) 9 (12)
0 0 0 1 0 1 2
22 19 21 19 16 14 7-i-l
A B C D E F Total PAN, Panoramic
Times PAN or FMX produced 21 change when ordered together (total changes)
radiograph.
Table V. Analysis of effect of sequenceof ordering radiographs on changes to diagnosis and treatment plan
in certainty or number of radiographs, by choice of first radiograph Radiograph ordered first
Median No. of participants in group
LC Panoramic FMX
Impact of the radiographs process
No. of additional radiographs ordered
20 11 5
2 2 2
on the diagnostic
Table III shows that only 192 of the 741 radiographs, or 26%, produced a change in either the participant’s diagnosis, treatment plan, or both. These 192 radiographs produced a total of 268 changes,because one radiograph could effect diagnosis, treatment plan, or both. There were on average 1.1 changes made to a diagnosis or treatment plan by each participant per case. When diagnosis and treatment were considered together, the number of changes varied from a low of 25 for case A to a high of 59 for case B (Table II). McNemar’s test of symmetry showed that significantly more changes were produced in treatment plans than in diagnoses (x2 = 6.75, p < 0.05). Of the 549 films that did not influence diagnosis or treatment, the participants reported that 528 of the radiographs confirmed information for their diagnosis and 448 confirmed part or all of their treatment plan. The LC radiograph produced the greatest number of changes, followed by the panoramic radiograph (Table III). Approximately 30% of the LC and panoramic radiographs produced one or more changes. Productivity dropped to a low of one change of 28 for occlusal radiographs or 3.6% productivity. Each casereceived either a panoramic or an FMX, or both. The panoramic and FMX were ordered together in 114 instances. To test the utility of ordering both a panoramic and an FMX on the same patient, we examined the number of changes that
Increase in certainty
Certainty
unchanged
(%1
f%6)
9.9 5.8 4.4
38 60 62
occurred as a result of the panoramic and FMX when they were both ordered for the samepatient. In Table IV, we see that, of those 111 instances, one or more changes resulted from 49 of the panoramic and/or FMX radiographs. However, in only two instancesdid both the panoramic and the FMX produce a change when ordered together. For patient D one orthodontist usedthe panoramic to “stage the treatment for the extraction of third molar” and the FMX to “inform the patient of root resorption potential.” For patient F the reasonsfor change were “the maxillary incisors are immature, wait for development before bonding” (FMX) and “the maxillary second molars are high, wait before using a high-pull headgear” (panoramic). Sequence of ordering radiographs
The LC radiograph was the first radiograph requested by participants 5 1% of the time, followed by the panoramic and FMX. Only these three examinations were chosenregularly as the first radiograph ordered. Becausethe first two radiographs produced the greatest certainty, we wished to determine whether any particular sequencewould provide the most beneficial information to the participant. First, we tested whether choosing any specific one of the three would influence the total number of radiographs that the orthodontist ordered. As seen in Table V, there was no difference among the three examinations in this respect. Orthodontists were equally as likely to order two additional radiographs regardless of which radiograph they ordered first. Next, the question as to
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whether any of the three radiographic examinations produced the greatest burst in confidence after interpretation was examined. To do this, the percentage of those participants who, having ordered the radiograph, did not change their certainty and the percent increase in certainty for those participants who did increase their certainty were evaluated. Table V demonstratesthat the LC examination produced both the largest percent increase for those who did change their certainty and the fewest participants who did not change their certainty. DISCUSSION
Examining the contribution of the radiographs to the orthodontist’s certainty, one is struck by the confidence of the orthodontists in diagnosing and planning treatment on the basis of the nonradiographic records. Despite the unfamiliar task of formulating a diagnosis and treatment plan when using another orthodontist’s records, and without the benefit of seeing the patient, the orthodontists were on average 75% certain of their diagnosis before reviewing any radiographs. The certainty with the treatment plan, although lower, was 69%. The fact that the orthodontists were less confident of their treatment plan than of their diagnosis may reflect their experience that understanding the problem does not always ensure a successful solution. Although one might question whether a participant’s certainty can be equated with accuracy, diagnoseswere, with a couple of minor exceptions, consistent with those prepared in the dental school clinic. These data are substantiated by Han et al l2 who compared the accuracy of diagnostic decisions formulated on the basis of information by using several permutations of initial records, ranging from solely study models to study models, facial photographs, and radiographs. They found that 54.9% of the treatment decision was afforded by the study models alone, reinforcing the expressedcertainty reported by our participants. The degree of uncertainty that the orthodontists were willing to accept before being comfortable and ready to begin treatment of a patient is also somewhat surprising. The average final certainty was far less than 100% for either diagnosis or treatment plan. In part this may be due to the artificial nature of the study, but participants expressedno special reservations of this nature. It may demonstrate the degree to which orthodontists believe patient compliance or behavior may affect the treatment plan and treatment response,factors over which they had no knowledge in this test, and the lack of a patient examination. Two distinct certainty patterns were noted among the orthodontists. Although the majority reported confidence gains from viewing radiographs, a minority of approximately 30% of the orthodontists ex-
presseda certainty based on the clinical information alone and never changed their certainty even though they continued to request and examine radiographs. This group’s initial mean certainty was considerably higher than that of those who changed certainty on the basis of the radiographic information. Neither the proportion of changes to the diagnostic process nor the content of the diagnosis or treatment plan was different from the group whose certainty changed on the basis of the radiographs. Therefore the contribution of the radiographs to this group’s diagnostic processis not clear and may have indicated a lack of desire to play the game we were imposing on them. As expected, on the basis of previous work,s orthodontists ordered the LC, panoramic, and FMX examinations most frequently. Theseexaminations were generally among the first radiographs ordered and accounted for a large proportion of the gain in certainty expressed by the participants. The examinations also accounted for the majority of the changes produced to the diagnostic process.The remaining or supplemental radiographs were each ordered in 25% or fewer of the available opportunities. The sequence chosenby the participants did not affect the efficiency of the examinations, in terms of number of radiographs. The individual orthodontist and the specific case were both important factors in explaining differences in the total number of radiographs ordered, with the individual orthodontist as the more important variable. The difficulty of the case, as assessedby the orthodontist, did not appear to explain the difference in number of radiographs ordered. This finding suggests that for ordering radiographs, variations in training or experience are important variables to consider. It suggeststhat ordering patterns may be based on predetermined factors rather than on patient characteristics. The diagnosesand treatment plans underwent only 268 changesas a result of information procured from the radiographic examinations, or approximately 1.1 change per case. The majority of the radiographs, 74%, did not cause a change in either the diagnosis or treatment plan. Most of these radiographs confirmed information previously available and may have contributed to the participant’s confidence. Although this is certainly an important benefit to the practitioner, it is not clear that the information provided additional benefit in terms of the overall management of the patient. Radiographs that bolster clinicians’ confidence in their decisions are valuable. However, radiographs ordered to document clinical findings, with no concomitant increase in confidence, are not valuable. Factors such as medical-legal concerns could lead a practitioner to order radiographs in the absence of clinical evidence of need. This does not offer an out-
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right benefit to patient management and is not sufficient reason to order radiographs. The development of guidelines to protect the practitioner from ordering radiographs for such reasons would benefit patient and practitioner alike. Examining the impact of a combination of radiographs (panoramic and FMX) that provide largely duplicative information when they were ordered together, we found that the percentage of radiographs not productive of changeswas even higher. In 98% of the combinations, at least one of the radiographs was unproductive. This is supported by the work of White et a1.,13who found that of 814 general dental patients who received both a panoramic and an FMX, in only one case did the panoramic supply information beyond the FMX that resulted in a change to the treatment plan. Critical evaluation of the orthodontist’s rationale for ordering the pair must be conducted to determine the justification for ordering apparently redundant examinations. On the basis of the findings of this study, it appears not justified to routinely order both a FMX and a panoramic radiograph for pretreatment orthodontic records, Perhaps it would be appropriate to order a panoramic and supplemental anterior periapical views, because the anterior teeth are often poorly visualized on panoramic views. Clearly, too many radiographic views in an orthodontic examination are unproductive. What is the cost of these unproductive radiographs? For the patient, cost can be measured two ways. One cost involves the additional expense related to the orthodontic treatment. The second cost relates to the biologic risk associated with the exposure to radiation implied through the exposure of the radiographic examination. In the interest of reducing these costs while maintaining a high level of productivity among radiographic examinations, additional work is needed to identify patient characteristics that suggest that a specific radiograph will be productive in aiding clinical management. The frequency of unproductive radiographs may thus be reduced from orthodontic diagnosis. CONCLUSIONS
1. Orthodontists showed great aptitude at discerning orthodontic problems on the basis of the information apparent in nonradiographic orthodontic records. 2. Approximately three fourths of the radiographs exposed for orthodontic evaluations did not
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contribute original information pertaining to the patient’s diagnosis or treatment plan. 3. The LC, panoramic, and FMX radiographic examinations are the most commonly ordered and the most productive examinations. 4. The panoramic and FMX provided duplicative information, and rarely did both contribute original diagnostic information. 5. Development of patient selection criteria for ordering pretreatment orthodontic radiographs may aid in selection of which radiographs should be ordered for patient problems and reduce the frequency of unproductive films. We acknowledgethe generoustime and effort of the orthodontistswhoparticipatedin this study,andthe statistical assistanceof Drs. Jeff Gornbeinand Jack Lee. REFERENCES 1. Graber TM. Orthodontic principles and practices. 3rd ed.
Philadelphia: WB Saunders, 1972:397-402. 2. Jarabak JR, Fizzell JA. Technique and treatment with light-
wire edgewise appliances; vol 1. 2nd ed. St Louis: CV Mosby, 1972~13%56. 3. Moyers RE. Handbook of orthodontics. 2nd ed. Chicago: Year Book Medical Publishers, 1963:209-20. 4. Proffit WR, Ackerman JL. Diagnosis and treatment planning in orthodontics In: Graber TM, Swain BF. Orthodontics: current principles and techniques. St Louis: CV Mosby, 1985: 45-85. 5. Renfro EW. Edgewise. Philadelphia: Lea & Febiger, 1975: 272-88. 6. Salzmann JA. Orthodontics in daily practice. Philadelphia: JB
Lippincott, 1974:167-96. 7. American Association of Orthodontists. Guidelines for quality
8. 9. 10.
11. 12.
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assessmentof orthodontic care. St. Louis: American Association of Orthodontists, 1988. Atchison KA. Radiographic examinations of orthodontic educators and practitioners. J Dent Ed 1986:50:651-5. Neiberg LG, Sinclair PM. A survey of predoctoral orthodontic education. J Dent Ed 1988;52:205-7. Food and Drug Administration. The selection of patients for x-ray examinations. US Department of Health, Education and Welfare, Publication, 80-8104, 1980:5-17. Woolson RF. Statistical methods for the analysis of biomedical data. New York: John Wiley & Sons, 1987:205. Han U, Vig P, Weintraub J. Consistency of orthodontic treatment decisionsrelative to diagnostic records [Abstract]. J Dent Res 1989;68:233. White SC, Forsythe AB, Joseph LP. Patient-selection criteria for panoramic radiography. ORAL SURG ORAL MED ORAL PATHOL1984;57:681-90.
Reprint requests to:
Kathryn Atchison, DDS, MPH UCLA School of Dentistry Center for the Health Sciences Los Angeles, CA 90024-1668
B
efore initiating orthodontic treatment, an orthodontist typically performs a medical and dental history and a comprehensive clinical examination. Additional orthodontic records assembledfor patients include photographs, study models, and a radiographic examination. The primary purpose of the radiographic examination is to provide additional information that may not be evident clinically. A review of orthodontic textbooks revealed that most texts do not make recommendations for a standard radiographic survey; rather, they describe films that may be useful in diagnosis and treatment planning.lV6The most frequently recommendedviews are full-mouth periapical and bitewing radiographs (FMX) and/or a panoramic radiograph and a lateral cephalometric (LC) radiograph. Other projections less frequently suggestedincluded the 45degree LC radiograph, occlusal radiograph, hand-wrist radiograph, lateral jaw radiograph, posterior-anterior cephalometric (PAC) radiograph, and temporomandibular (TMJ) projections. Recently published American Association of Orthodontists guidelines’ recommend that an LC and a panoramic or complete intraoral radiographs should be used for orthodontic aAssistant Professor, Section of Public Health Dentistry. bCIinical Professor, Sections of Pediatric Dentistry and Orthodontics. cProfessor,Section of Oral Radiology. 7/M/20721 238
diagnosis and treatment planning of comprehensive cases. A survey of practicing orthodontists confirmed that these recommendations are generally followed. A questionnaire distributed to dental schools and individual orthodontic practitioners by Atchison* in 1985 reported that more than 90% of the orthodontists responded that they order an LC and panoramic radiograph for their patients with permanent dentition. Approximately 70% reported ordering them on patients in the primary and early mixed dentition. The remainder of the radiographs were ordered 40% of the time or less for patients. The results further showed that the number of pretreatment radiographs ordered dependedon the orthodontist’s type of practice (educator vs private practitioner) and age of the patient. Educators reported ordering 1.4 times as many radiographs as private practitioners. More orthodontists reported ordering radiographs for patients older than 10 years of age than for younger patients. Nieberg and Sinclair9 found similar results in a survey of predoctoral orthodontic programs. They report that the majority of the schools report requesting FMX, a panoramic, and an LC radiograph as part of the diagnostic records for some or all their patient cases. It is not clear, however, how much radiographs contribute to the orthodontist’s diagnostic and treatment planning process.Recent concern expressedby the public as well as by clinicians about accruing ion-
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Table I. Patient characteristics for the six test cases
AgeWI Case
sex
A B C D E F
12/M 13/M 19/M 18/M 26/F
8/F
Skeletal classification
I 11 II I I II
Midline deviation
Posterior crossbites
Lower face height
Molar crowding
No Yes No No Yes
None None None Bilateral Bilateral Unilateral
Normal Long Short Long Normal Normal
Yes Yes No Yes No No
izing radiation has spurred an evaluation of diagnostic radiation use to determine the contribution of radiographs to the clinician’s management of patients. The intent of such evaluations is to examine the efficacy of radiographs, alone and in combinations, in terms of their contribution to diagnosis and treatment planning.‘O The purpose of this study was to determine quantitatively the amount of diagnostic and treatment planning information gained by orthodontists when radiographs are added to a set of orthodontic records and a previously charted medical and dental history and oral examination. MATERIAL AND METHODS Overview
In the present study, orthodontists were shown six casesand asked to diagnose (enumerate the problems presented in) each caseand describe a treatment plan (solution for problems). Each orthodontist then estimated the gain in confidence resulting from examination of successive,selectedradiographs until they felt confident they had all diagnostic information they needed to proceed with patient care. Study cases
The study models and records of six patients seen for orthodontic consultation at the University of California-Los Angeles orthodontic clinic were selected and duplicated (maintaining the patients’ confidentiality). The cases,as seenin Table I, were chosen to represent common malocclusion problems treated by orthodontists. These included two casesof asymmetry, three molar crowding, three posterior crossbites,and one anterior open bite case.The initial records consisted of a medical and dental history, study models, intraoral and extraoral photographs, a charting of the patient’s oral examination, and the radiographs chosen by the supervising faculty orthodontist. The minimum set of radiographs consisted of an FMX, a panoramic, maxillary and mandibular occlusals, LC and PAC views, a carpal index (CI), and lateral TMJ or transcranial tomograms. In addi-
tion, several caseshad a submental vertex radiograph present, which was duplicated and included with the minimum set. Participants
A letter was sent to members of the Pacific Coast Society of Orthodontists who resided in the west Los Angeles and the near San Fernando Valley. Orthodontists were asked to return a form with their telephone number if they were willing to participate in a research project dealing with the radiographs usedfor orthodontic diagnosis. A letter was also sent to the faculty of two orthodontic programs. The authors telephoned 40 responding orthodontists and explained that participation involved a 2-hour interview during which the participant would evaluate patient cases. Orthodontists were assured that we were not testing the accuracy of their diagnosis or treatment plan but, rather, were evaluating the specific information orthodontists use to formulate their diagnosis and treatment plans. Interview
format
A standardized interview schedule was developed and pilot tested on four faculty orthodontists, and appropriate refinements were made. For each case the participant was presented first with the study models, intraoral and extraoral photographs, and the charting of the oral examination. They were asked to formulate a diagnosis and describe it to the interviewer. They were then asked to estimate their degree of certainty that the diagnosis was accurate and complete. This was recorded on a percent confidence visual analog scale ranging from 0% confidence (basically a pure guess) to 100% confidence (absolute certainty) that the diagnosis was correct. This process was repeated for the treatment plan. The interviewer then informed the participant that radiographs could be requested individually if needed to complete the diagnosis or treatment plan. The Ricketts, Downs, Steiner, Wits, Harvold, and Sassouni analyses were presented when an LC radiograph was requested. Some participants did their own analysis. The FMX
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was given whenever a portion of it was requested, although the part specified was recorded. Each participant was asked to describe the reasons for ordering each radiograph. After examining the radiograph, the orthodontist summarized the diagnostic information gleaned from the radiograph and noted whether it caused a change, confirmation, or enhancement to the diagnosis. The participant’s new certainty with the diagnosis was recorded. He or she was then asked whether the radiograph caused any change, confirmation, or enhancement to the treatment plan and to estimate his or her new certainty with the treatment plan. The processwas repeated for each additional radiograph the participant requested until the participant felt comfortable that all the information about the patient, short of seeing the patient personally, had been gathered. At this point the participant’s final certainty with both diagnosis and treatment plan was recorded. He or she was then asked to estimate the difficulty of the case and describe any additional records that would be needed for this patient. This processwas repeated for the remaining five cases.One case,selected by the authors as an easily diagnosedcase,was always presentedfirst and the order of the remaining five cases was randomized to prevent a possible fatigue effect. Data analysis
Analysis was conducted on each patient case individually (six groups). In addition, all caseswere combined. The information sought from each case included (1) the participant’s level of initial and final certainty with the diagnosis and treatment plan, (2) the impact of the radiographs on diagnosis and the treatment plan, (3) the number, type, and order in which radiographs were selected, (4) the difficulty of each case, (5) the information sought from each radiograph, and (6) the information provided by the radiographs. An impact was defined as either a change or confirmation to the diagnosis or treatment plan. The difficulty of each casewas assessedby the participant, at completion of the caseas a 1 for an easycase, 2 for a typical case, and 3 for a difficult case. A diffculty index was calculated for each patient caseby calculating the mean number assessedper case. Four separate lines of analysis were used to evaluate the contribution of the radiographs to the diagnosis and treatment plan. The first analysis assessedthe change in the participant’s confidence or certainty as clinical and radiographic information about the patient was received. We expected that additional information should act to increase the participants’ certainty with their diagnoses and treatment plans until they would declare themselvessatisfied with the information and ready, hypothetically, to treat the patient. Distributions of individual participants’ di-
agnostic and treatment certainty were plotted by case and in total. Analysis of variance with repeated measures was used to test whether participants’ initial diagnostic certainty (before reviewing any radiographs) varied by case,and whether the difficulty of the case was reflected in the participants’ certainty. This was repeated for the treatment certainty. Next, the number of radiographs ordered and which individual radiographs were ordered for each caseby a participant were evaluated. A greater number of radiographs suggestedto us a greater requirement for diagnostic information to analyze the case. Further, examinations that are requested more frequently would reasonably be expectedto contribute to the diagnostic process. Descriptive statistics were calculated by case, by participant, and in total. A never-use indicator was also derived to assesshow widespread the use of individual radiographic examinations are among the orthodontists studied. This indicator was computed by tabulating the percentage of participants who never ordered a particular projection for any of the six test cases.Analysis of variance with repeated measures, with the number of radiographs ordered as the dependent variable and the patient case and the orthodontist as controlling variables, was conducted. Analysis of covariance, with the difficulty index as the covariate, was also conducted. To determine the degree to which orthodontists agree on which radiographs to order for patients, a homogeneity value was developed and calculated for each radiograph. The homogeneity value considers the degree of agreement among orthodontists regarding whether to order a particular radiograph for each case.Scorescan range from 0 to 1. The optimal score of 1 is reached when all orthodontists agree either in favor of ordering the radiograph or not, whereas a scoreof 0 indicates that half the orthodontists ordered the film and half did not. A score of lessthan 0.7 signifies substantial disagreement among the orthodontists on when the radiograph is indicated. The equation for the homogeneity value is
H=
[
2, c=
x1
W)l
1 /
(42)
where H = homogeneity value, x = the number of participants who ordered a radiograph for the specific case, n = the number of participants, and i = the number of cases. Descriptive statistics were also used to evaluate the impact of individual radiographs. The percentage of radiographs that caused a change in either the diagnosis or treatment plan was determined, to evaluate the efficacy or productivity of each type of film. To test
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Orthodontist % Certainty
24 1
.O- Treatment
_Clln. Rev.
5
;
6
Number radiographs requested
Fig. 1. Distribution represents certainty of average practitioner regarding diagnosis and treatment plan both before and after reviewing radiographs. Standard deviation is shown in parentheses (n = 39).
Of the 40 orthodontists who began the interview, 39 completed all six cases. The final participant had completed three casesat the end of 2 hours and did not wish to donate further time to the project. The data analysis is based on only the 39 complete sets of data.
the radiographic examination. This group reported a higher mean certainty before reviewing any radiographs. Difficulty scorescould range from 1 for an easycase to 3 for a difficult case.The mean difficulty rating assigned to each case by the orthodontists and the certainties for the various casesare compared in Table II. The initial diagnostic certainty after clinical review but before reviewing any radiographs varied among the six caseswhen examined using analysis of variance. Case A, with a high of 80% certainty, was significantly different from caseD, which had a mean certainty of 69%. The use of difficulty rating as a covariate did not explain this difference. The average final diagnostic certainty, based on all diagnostic information present, was approximately 88%. Certainty values for treatment plans were consistently less than for diagnosis, but in only two cases,D and E, was the difference between treatment plan and diagnosis significant at the 0.05 (Ylevel.
Change in participants’
Number and type of radiographs
for a difference in the proportion of changes made to diagnosis versus treatment plan, McNemar’s test of symmetry’ ’ was used. Finally, the sequenceof ordering the radiographic examinations was examined to seewhether sequence affected the outcome of the casein terms of certainty or number of films ordered. To do that, we examined how many additional radiographs an orthodontist ordered after the first radiograph, when the first radiograph was an LC, a panoramic, or an FMX. The increasein certainty after the first radiograph was also examined. RESULTS
certainty
The certainty distribution for each test case was examined. Finding a similar trajectory for each case, the caseswere grouped together for easeof presentation. Fig. 1 shows that the participants were on average 75% certain of their diagnosis and 70% certain of their treatment plan before reviewing any radiographs. Further, participants gained the majority of their confidence on the basis of information observed on the first two or three radiographs. When gains in confidence for individual participants were examined, two unique distributions for the participants were found. Most of the participants followed the trajectory projected in Fig. 1. Approximately 30% of the participants (ranging from 6 to 14 participants, depending on the case), however, never changed their certainty as a result of a radiograph. Thus for these orthodontists the certainty with the diagnosis and treatment expressed after examining the initial records represented the same certainty at the end of
ordered
Participants ordered a total of 741 radiographs to complete diagnoses and treatment plans for the six cases. The total number of radiographs ordered by participants for the casesranged from 12 to 3 1, or an average of 3.2 radiographic examinations per case. The number of examinations ordered varied significantly only between cases D and F (Table II). The fewest radiographs were ordered for casesA and F. The difficulty of the casedid not explain the variation between casesin terms of the number of radiographs requested by the participant. As seenin Table III, the LC was ordered most frequently, followed by the panoramic and the FMX. Other radiographic examinations were ordered much lessfrequently (one fourth or less of the available opportunities). Another indication of thevariation in the ordering behavior is how many orthodontists never use a particular radiograph for any patient. The never-use indicator in Table III shows that the LC, pan-
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Table II. Description of case difficulty, number of radiographs ordered, and initial and final certainty with diagnosis and treatment plan -
Case
Mean dificulty rating
A B C D E F *Significant
1.6 2.6 2.8 2.8 2.7 2.3
% diagnostic certainty (mean k SD) Initial 80* 76 76 69* 75 75
+ rt k k * +
% treatment plan certainty (mean k SD)
Final
17.4 19.2 18.3 25.4 19.3 22.9
91 88 86 85 87 88
+ + k + + 2
Initial
14.4 15.6 17.6 15.6 15.8 16.8
16 69 70 61 65 68
Final
+ 20.6 t 24.1 -+ 19.2 + 25.3 +- 23.8 r 22.9
91 84 83 82 81 86
k 14.6 k 19.7 f 17.8 + 18.2 + 18.5 -+ 15.7
Mean No. of radiographs
No. of diagnosis changes
I
3.0 3.4 3.1 3.5* 3.2 3.0*
25
10 20 29 29
No. of treatmeni changes 18 34 18 35
I5 28
differences among cases; p < 0.05.
Table Ill. Number of radiographs ordered and resulting changes produced in participant’s diagnosis and treatment plan Radiographs
No. ordered
LC Panoramic FMX PAC TMJ Occlusal CI Submental vertex Total *Two additional
230
178 170 59 58 28 13 3
741*
No. of changes
No. producing ~1 change
Diagnostic
71 59 35 13
10 1 1
Treatment
Total
46 32 26 7 8
55 50 26 8 6
101
0 0
I 1 1 148
1 1
2
2
192
120
82 52 15 14
2
Never use (%)
0 10 3 44 49 12 82 92
Homogeneity 0.97 0.52 0.45 0.50 0.50 0.76 0.89 0.97
268
radiographs were ordered, a lateral jaw and a serial lateral head plate, which were not available for examining.
oramic, and the FMX were ordered by 90% or more of the orthodontists. Slightly less than half the participants never ordered PAC or TMJ projections. The remaining three radiographs were ordered by 30% or fewer of the participants. Seventeenof the 39 participants (44%) never ordered a PAC, and 32 participants (82%) never ordered a CI. The homogeneity value quantifies the amount of agreement among the participants on when each specific radiograph was indicated for an individual case. Table III shows that the LC and the CI both showed good agreement among participants as to when they are indicated. The LC wasordered almost universally, and the CI was rarely ordered. Radiographs such as the panoramic, FMX, PAC, and TMJ showed poor agreement as to when they are indicated. For the panoramic and FMX, one was always ordered, but the participants did not agree on which to order. To test whether the patient case or the individual orthodontist was more important in determining how many total radiographs were ordered for the cases,we compared the variability in number of radiographs ordered among orthodontists with the variability of radiographs for the cases. The mean number of radiographs ordered by the participants ranged from
2.0 to 5.7 radiographs per case.The comparable range for the mean number of radiographs per test casewas 3.0 to 3.5 radiographs. Thevariation (as measured by the standard deviation) associatedwith the individual orthodontist was approximately 1.6 times greater than that associated with the patients case. Because an LC examination and either a panoramic or an FMX were ordered nearly universally, a separate analysis was performed on the ordering of lessfrequently ordered radiographs, the supplemental radiographs. A mean of 0.7 supplementary radiographs were ordered per patient. We compared the variability among orthodontists and patient casesfor the number of supplemental radiographs. The mean number of supplementary films ranged from 0 to 2.5 radiographs for the participants. For the test casesit varied from 0.4 to 0.9 radiographs. The proportion of variation (as measuredby the standard deviation) associated with the orthodontist was appruximately 1.2 times greater than that of the patient case. Thus for both total number of radiographs and the supplementary radiographs the individ~lorthodontistwas more important than the patient case in explaining the variance associated with the number of radiographs ordered during the diagnostic process.
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Table IV. Use of panoramic and FMX examinations for a single patient Times both PAN and Fh4X used together
Patient
Times both PAN and FMX changed diagnosis or treatment when ordered together
7 (9) 13 (22) 7 (9) 7 (13) 9 (12)
0 0 0 1 0 1 2
22 19 21 19 16 14 7-i-l
A B C D E F Total PAN, Panoramic
Times PAN or FMX produced 21 change when ordered together (total changes)
radiograph.
Table V. Analysis of effect of sequenceof ordering radiographs on changes to diagnosis and treatment plan
in certainty or number of radiographs, by choice of first radiograph Radiograph ordered first
Median No. of participants in group
LC Panoramic FMX
Impact of the radiographs process
No. of additional radiographs ordered
20 11 5
2 2 2
on the diagnostic
Table III shows that only 192 of the 741 radiographs, or 26%, produced a change in either the participant’s diagnosis, treatment plan, or both. These 192 radiographs produced a total of 268 changes,because one radiograph could effect diagnosis, treatment plan, or both. There were on average 1.1 changes made to a diagnosis or treatment plan by each participant per case. When diagnosis and treatment were considered together, the number of changes varied from a low of 25 for case A to a high of 59 for case B (Table II). McNemar’s test of symmetry showed that significantly more changes were produced in treatment plans than in diagnoses (x2 = 6.75, p < 0.05). Of the 549 films that did not influence diagnosis or treatment, the participants reported that 528 of the radiographs confirmed information for their diagnosis and 448 confirmed part or all of their treatment plan. The LC radiograph produced the greatest number of changes, followed by the panoramic radiograph (Table III). Approximately 30% of the LC and panoramic radiographs produced one or more changes. Productivity dropped to a low of one change of 28 for occlusal radiographs or 3.6% productivity. Each casereceived either a panoramic or an FMX, or both. The panoramic and FMX were ordered together in 114 instances. To test the utility of ordering both a panoramic and an FMX on the same patient, we examined the number of changes that
Increase in certainty
Certainty
unchanged
(%1
f%6)
9.9 5.8 4.4
38 60 62
occurred as a result of the panoramic and FMX when they were both ordered for the samepatient. In Table IV, we see that, of those 111 instances, one or more changes resulted from 49 of the panoramic and/or FMX radiographs. However, in only two instancesdid both the panoramic and the FMX produce a change when ordered together. For patient D one orthodontist usedthe panoramic to “stage the treatment for the extraction of third molar” and the FMX to “inform the patient of root resorption potential.” For patient F the reasonsfor change were “the maxillary incisors are immature, wait for development before bonding” (FMX) and “the maxillary second molars are high, wait before using a high-pull headgear” (panoramic). Sequence of ordering radiographs
The LC radiograph was the first radiograph requested by participants 5 1% of the time, followed by the panoramic and FMX. Only these three examinations were chosenregularly as the first radiograph ordered. Becausethe first two radiographs produced the greatest certainty, we wished to determine whether any particular sequencewould provide the most beneficial information to the participant. First, we tested whether choosing any specific one of the three would influence the total number of radiographs that the orthodontist ordered. As seen in Table V, there was no difference among the three examinations in this respect. Orthodontists were equally as likely to order two additional radiographs regardless of which radiograph they ordered first. Next, the question as to
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whether any of the three radiographic examinations produced the greatest burst in confidence after interpretation was examined. To do this, the percentage of those participants who, having ordered the radiograph, did not change their certainty and the percent increase in certainty for those participants who did increase their certainty were evaluated. Table V demonstratesthat the LC examination produced both the largest percent increase for those who did change their certainty and the fewest participants who did not change their certainty. DISCUSSION
Examining the contribution of the radiographs to the orthodontist’s certainty, one is struck by the confidence of the orthodontists in diagnosing and planning treatment on the basis of the nonradiographic records. Despite the unfamiliar task of formulating a diagnosis and treatment plan when using another orthodontist’s records, and without the benefit of seeing the patient, the orthodontists were on average 75% certain of their diagnosis before reviewing any radiographs. The certainty with the treatment plan, although lower, was 69%. The fact that the orthodontists were less confident of their treatment plan than of their diagnosis may reflect their experience that understanding the problem does not always ensure a successful solution. Although one might question whether a participant’s certainty can be equated with accuracy, diagnoseswere, with a couple of minor exceptions, consistent with those prepared in the dental school clinic. These data are substantiated by Han et al l2 who compared the accuracy of diagnostic decisions formulated on the basis of information by using several permutations of initial records, ranging from solely study models to study models, facial photographs, and radiographs. They found that 54.9% of the treatment decision was afforded by the study models alone, reinforcing the expressedcertainty reported by our participants. The degree of uncertainty that the orthodontists were willing to accept before being comfortable and ready to begin treatment of a patient is also somewhat surprising. The average final certainty was far less than 100% for either diagnosis or treatment plan. In part this may be due to the artificial nature of the study, but participants expressedno special reservations of this nature. It may demonstrate the degree to which orthodontists believe patient compliance or behavior may affect the treatment plan and treatment response,factors over which they had no knowledge in this test, and the lack of a patient examination. Two distinct certainty patterns were noted among the orthodontists. Although the majority reported confidence gains from viewing radiographs, a minority of approximately 30% of the orthodontists ex-
presseda certainty based on the clinical information alone and never changed their certainty even though they continued to request and examine radiographs. This group’s initial mean certainty was considerably higher than that of those who changed certainty on the basis of the radiographic information. Neither the proportion of changes to the diagnostic process nor the content of the diagnosis or treatment plan was different from the group whose certainty changed on the basis of the radiographs. Therefore the contribution of the radiographs to this group’s diagnostic processis not clear and may have indicated a lack of desire to play the game we were imposing on them. As expected, on the basis of previous work,s orthodontists ordered the LC, panoramic, and FMX examinations most frequently. Theseexaminations were generally among the first radiographs ordered and accounted for a large proportion of the gain in certainty expressed by the participants. The examinations also accounted for the majority of the changes produced to the diagnostic process.The remaining or supplemental radiographs were each ordered in 25% or fewer of the available opportunities. The sequence chosenby the participants did not affect the efficiency of the examinations, in terms of number of radiographs. The individual orthodontist and the specific case were both important factors in explaining differences in the total number of radiographs ordered, with the individual orthodontist as the more important variable. The difficulty of the case, as assessedby the orthodontist, did not appear to explain the difference in number of radiographs ordered. This finding suggests that for ordering radiographs, variations in training or experience are important variables to consider. It suggeststhat ordering patterns may be based on predetermined factors rather than on patient characteristics. The diagnosesand treatment plans underwent only 268 changesas a result of information procured from the radiographic examinations, or approximately 1.1 change per case. The majority of the radiographs, 74%, did not cause a change in either the diagnosis or treatment plan. Most of these radiographs confirmed information previously available and may have contributed to the participant’s confidence. Although this is certainly an important benefit to the practitioner, it is not clear that the information provided additional benefit in terms of the overall management of the patient. Radiographs that bolster clinicians’ confidence in their decisions are valuable. However, radiographs ordered to document clinical findings, with no concomitant increase in confidence, are not valuable. Factors such as medical-legal concerns could lead a practitioner to order radiographs in the absence of clinical evidence of need. This does not offer an out-
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right benefit to patient management and is not sufficient reason to order radiographs. The development of guidelines to protect the practitioner from ordering radiographs for such reasons would benefit patient and practitioner alike. Examining the impact of a combination of radiographs (panoramic and FMX) that provide largely duplicative information when they were ordered together, we found that the percentage of radiographs not productive of changeswas even higher. In 98% of the combinations, at least one of the radiographs was unproductive. This is supported by the work of White et a1.,13who found that of 814 general dental patients who received both a panoramic and an FMX, in only one case did the panoramic supply information beyond the FMX that resulted in a change to the treatment plan. Critical evaluation of the orthodontist’s rationale for ordering the pair must be conducted to determine the justification for ordering apparently redundant examinations. On the basis of the findings of this study, it appears not justified to routinely order both a FMX and a panoramic radiograph for pretreatment orthodontic records, Perhaps it would be appropriate to order a panoramic and supplemental anterior periapical views, because the anterior teeth are often poorly visualized on panoramic views. Clearly, too many radiographic views in an orthodontic examination are unproductive. What is the cost of these unproductive radiographs? For the patient, cost can be measured two ways. One cost involves the additional expense related to the orthodontic treatment. The second cost relates to the biologic risk associated with the exposure to radiation implied through the exposure of the radiographic examination. In the interest of reducing these costs while maintaining a high level of productivity among radiographic examinations, additional work is needed to identify patient characteristics that suggest that a specific radiograph will be productive in aiding clinical management. The frequency of unproductive radiographs may thus be reduced from orthodontic diagnosis. CONCLUSIONS
1. Orthodontists showed great aptitude at discerning orthodontic problems on the basis of the information apparent in nonradiographic orthodontic records. 2. Approximately three fourths of the radiographs exposed for orthodontic evaluations did not
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contribute original information pertaining to the patient’s diagnosis or treatment plan. 3. The LC, panoramic, and FMX radiographic examinations are the most commonly ordered and the most productive examinations. 4. The panoramic and FMX provided duplicative information, and rarely did both contribute original diagnostic information. 5. Development of patient selection criteria for ordering pretreatment orthodontic radiographs may aid in selection of which radiographs should be ordered for patient problems and reduce the frequency of unproductive films. We acknowledgethe generoustime and effort of the orthodontistswhoparticipatedin this study,andthe statistical assistanceof Drs. Jeff Gornbeinand Jack Lee. REFERENCES 1. Graber TM. Orthodontic principles and practices. 3rd ed.
Philadelphia: WB Saunders, 1972:397-402. 2. Jarabak JR, Fizzell JA. Technique and treatment with light-
wire edgewise appliances; vol 1. 2nd ed. St Louis: CV Mosby, 1972~13%56. 3. Moyers RE. Handbook of orthodontics. 2nd ed. Chicago: Year Book Medical Publishers, 1963:209-20. 4. Proffit WR, Ackerman JL. Diagnosis and treatment planning in orthodontics In: Graber TM, Swain BF. Orthodontics: current principles and techniques. St Louis: CV Mosby, 1985: 45-85. 5. Renfro EW. Edgewise. Philadelphia: Lea & Febiger, 1975: 272-88. 6. Salzmann JA. Orthodontics in daily practice. Philadelphia: JB
Lippincott, 1974:167-96. 7. American Association of Orthodontists. Guidelines for quality
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assessmentof orthodontic care. St. Louis: American Association of Orthodontists, 1988. Atchison KA. Radiographic examinations of orthodontic educators and practitioners. J Dent Ed 1986:50:651-5. Neiberg LG, Sinclair PM. A survey of predoctoral orthodontic education. J Dent Ed 1988;52:205-7. Food and Drug Administration. The selection of patients for x-ray examinations. US Department of Health, Education and Welfare, Publication, 80-8104, 1980:5-17. Woolson RF. Statistical methods for the analysis of biomedical data. New York: John Wiley & Sons, 1987:205. Han U, Vig P, Weintraub J. Consistency of orthodontic treatment decisionsrelative to diagnostic records [Abstract]. J Dent Res 1989;68:233. White SC, Forsythe AB, Joseph LP. Patient-selection criteria for panoramic radiography. ORAL SURG ORAL MED ORAL PATHOL1984;57:681-90.
Reprint requests to:
Kathryn Atchison, DDS, MPH UCLA School of Dentistry Center for the Health Sciences Los Angeles, CA 90024-1668
