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Contemporary trends in orthodontic practice: A national survey
SPECIAL ARTICLE
Contemporary trends in orthodontic practice: A national survey Brian M. P. O'Connor, BDS, MS Dublin, Ireland This study involved the development of a questionnaire to elicit information about current trends in orthodontic practice compared with trends of 5 years ago, The subjects addressed included the use of fixed appliances, functional appliances, extraction therapy, orthodontics and the temporomandibular joint, current diagnostic aids, and medicolegal implications of orthodontic treatment. The questionnaire was mailed to 1400 orthodontic specialists who were randomly selected from across the United States. There were 814 questionnaires returned, representing a 58.14% response rate. The major results of this survey are as follows: (1) The reported extraction rate has declined from a mean of 37.74% 5 years ago to 29.28% today. (2) TMJ concerns (or medicolegal implications thereof) have had a considerable impact in this decline, with 26.4% of orthodontists being influenced, to some extent, to extract fewer teeth because of this factor. (3) The use of functional appliances has remained somewhat static over the last 5 years, after a period of rapid growth in the 5 years previous to that. (4) The preadjusted edgewise appliance is by far the most popular fixed appliance in tJse today, being chosen by 72.6% of respondents. Analysis of the overall results lead to the following conclusions: (1) Fixed appliance therapy is the therapy of choice of the overwhelming majority of orthodontists. The use, benefits, and role in orthodontics of functional appliance therapy is considerably less defined. (2) Treatment modalities, notably on the use of extraction and its relationship to the health of the temporomandibular joint, should be determined by research, not by legal fears or unsubstantiated allegation. (AMJ ORTHOODENTOFAC ORTHOP 1993;103:163-70.)
Factual information relating to changing trends in orthodontics is somewhat sparse. To avoid a fruitless repetition of past mistakes, it is important that any learned specialty document the various ebbs and flows of its progress. An individual member of that specialty should be able to make a considered judgment, not least on an historic basis, as to the efficacy of a particular appliance or concept of treatment that is offered to him. Is the appliance or concept new? How has it been tested? Is it accepted widely by his peers? At a time when the individual practitioner is confronted by a plethora of miracle devices, each promising to deliver the Holy Grail of orthodontic success, the present day orthodontist needs as much factual information as possible. In this context the present study was undertaken. Three main objectives were identified: (1) to assemble and document data on current trends in orthodontic practice, (2) to compare these trends with
Based on a thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry, Department of Orthodontics, St. Louis University. Copyright 9 1993 by the American AssoCiation of Orthodontists. 0889-5406193151.00 + 0.10 811131352
those of 5 years ago, and (3) to analyze the underlying reasons for any changes that might have occurred. The subjects addressed included the use of fixed appliance therapy, functional appliance therapy, extraction therapy, orthodontics and the temporomandibular joint (TMJ), current diagnostic aids, and medicolegal implications of orthodontic treatment.
MATERIALS AND METHODS A questionnaire was developed to elicit information about current trends in orthodontic practice compared with trends of 5 years ago. The questionnaire was mailed to 1400 active orthodontic specialists selected at random from the 1989 Director 5' o f Members o f the American Association o f Orthodontists. The sample ~vas regionally distributed, and the num-
ber sampled represents approximately 1 in 5 (20.68%) of the entire active AAO membership of the United States. The questionnaires were mailed in November 1989, and those returned by January 31, 1990, were accepted for the study. Special mention was made of the assurance of anonymity, and that it was unnecessary to sign the completed questionnaire. The questionnaire was four pages in length and consisted of 29 questions. In addition to asking the age, year of graduation, and state in which they practiced, each respondent was asked about the type of fixed orthodontic training they
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American Journal of Orthodontics and Dentofacial O,rthopedics February 1993
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Table I. Number and percentage of respondents from each age group
Table Ill. Number and percentage of
respondents by region of the United States Region
9Age group O'r)
Number
Percentage
27-40 41-50 51-60 >60
253 322 187 46
31.3 39.9 23.1 5.7
Valid responses to question no. l: 808. glean age: 45.69.
Great Lakes Middle Atlantic Midwestem Northeastern Pacific Coast Rocky Mountain Southern Southwestern
I
Number
I
Percentage
94 69 97 124 146 5! 155 76
I 1.6 8.5 12.0 15.3 17.9 6.3 19.0 9.4
Valid responses to question no. 3:81 I.
Table II. Number and percentage of respondents by years in practice Years in practice 0-5 6-10 11-20 >20
Number 49 168 354 2 3 7 , .:..
Percentage 6. ! 20.8 43.8 29.3
Valid responses to question no. 2: 808. Mean number of years in practice: 16.29.
received and what appliance(s) they currently used; their use and opinion of functional appliances; use of headgear; extraction frequency and rationale of use; etiology of TMJ and treatment; current diagnostic aids, and attitude to defensive practice. Where appropriate, comparisons were made with attitudes on similar topics 5 years ago. Responses on the returned questionnaires were analyzed at the Saint Louis University Medical Center. Data analysis was performed with the Statistical Package for the Social Sciences (SPSS). Descriptive statistics that were compiled included frequencies and means (where appropriate) of responses. Crosstabulations of selected variables (response options) were done, and where indicated, chi-square analyses were performed to determine whether these variables were independent of each other. In the analysis of questions that required quantitative responses, analysis of variance was used. A twotailed t test was used to compare the present extraction rate with that of 5 years ago. In all analyses,statistical significance was judged at the level p < 0.05. RESULTS
Of the 1400 questionnaires mailed to the randomly selected orthodontic specialists, 814 were returned, representing a 58.14% response rate. Data from the 814 returns were consolidated and statistically analyzed. Tables I through XXV depict frequency responses, means (where appropriate) and cross-tabulations. Frequency responses, unless otherwise stated, are given as a percentage of those respondents who replied to a
Table IV. Type of fixed orthodontic training mainly received Respondents Appliance
Number
I
Percentage
Begg Standard edgewise Preadjusted edgewise (straightwire) Johnson twin-wire 9Labial-lingual Lingual Other
183 674 271
22.6 83.1 33.5
61 59 22 31
7.5 7.3 2.7 3.8
particular question (i.e., the valid response) and not as a percentage of the whole sample. As there is some crossover of response to certain questions, with respondents possibly replying to more than one part of a question, percentages will not always total 100%. Practitioners were asked their present age, year of completion of specialist orthodontic training, and the state in which they practiced. Table I describes the number and percentage of respondents by age group (the mean age of respondents was 45.69 years). Table II describes the number and percentage of respondents by years in practice and shows a mean of 16.29 years. Because of the nature of the study the age group 0-5 may b~ underrepresented. Regional response rate is given in Table Ill. Table IV lists the type of fixed orthodontic training mainly received by respondents. Standard edgewise (83.1%) was by far the most common training modem for the sample overall, with preadjusted edgewise (33.5%) and Begg (22.6%) second and third, respectively. However, from Table V, it is clear that preadjusted edgewise (72.6%) is the strong favorite of respondents with standard edgewise (29%) being second, and Begg (5.6%) a remote third. Tables VI through XI are related to questions about
AmericanJournalof Orthodonticsand DentofacialOrthopedics Volume 103, No. 2 V. Type of fixed orthodontic treatment mainly us'ed at present
Table
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Table VII. Use of functional appliances
5 years ago
Respondents
Respondents Appliance
Number
Begg Standard edgewise Preadjusted edgewise Johnson twin-wire Labial-lingual Lingual Other
45 234 588 5 3 6 27
[
Percentage 5.6 29.0 72.6 0.6 0.4 0.7 3.3
Frequency of use
Number
Routinely Occasionally Rarely Never
198 358 133 93
[
Percentage 24.8 44.8 16.5 13.9
Valid responses: 800.
VIII. Use of functional appliances 10 years ago Table
9Table VI. Current use of functional appliances
Respondents Frequency o f Ilse
Number
Routinely Occasionally Rarely Never
200 367 149 93
[
Percentage 24.7 45.4 f. 18.4 11.5
Frequency of use Routinely Occasionally Rarely Never
Respondents [ Number Percentage 66 199 148 250
9.9 30.0 22.4 37.7
Valid responses: 809.
Valid responses: 664.
the use of functional appliances. Table VI shows that they are used routinely by approximately 1 in 4 orthodontists and never by approximately 1 in 10. This Osage is almost identical to that of 5 years ago (Table VII) but markedly different from 10 years ago (Table VIII). At that time, only 1 in 10 orthodontists used functional appliances routinely, whereas 1 in 3 never used them. The bionator was the functional appliance of choice of approximately one in two practitioners who use functional appliances (Table IX), being considerably more popular than any other appliance. The vast majority of respondents believe that in~;truction in the use of functional appliances is desirable in formal specialist training (Table X). The suggestion that functional appliances offer a definite alternative to fixed appliances is overwhelmingly rejected by respondents (Table XI). Rather, functiona ! appliances are viewed as either a frequently usefuladjunct to fixed theratB' (one in four respondents), or an occasionally useful one (one in two respondents). - Table XII shows that the use of headgear as an aid in Class II molar correction is very common, being used either routinely or occasionally by about 9 of every 10 orthodontists. Tables XIII through XV address one of the most important questions in this study, the use of extraction. Table XIII compares current frequency of extraction with 5 years ago, and shows that over half the respon-
dents extract fewer teeth now than they did then, whereas just 3.1% extract more. The extent of the drop is illustrated in Table XIV. From a mean reported extraction rate of 37.74% 5 years ago, the current extraction rate now stands at 29.28%, representing a highly significant drop of 22.41% (Pr = 0.000). The major reasons for the decline in the use of extraction (Table X V ) a r e given as a desire for improved facial esthetics (36.7% of the entire sample), orTMJ concems (14.9% of entire sample), or medicolegal concerns (9.8% of entire sample). Other reasons given by 17.9%. of respondents for extracting fewer teeth included better mechanotherapy, use of brackets versus bands, use of expansion, and use of early treatment. Tables XVI, XVII, and x V I I I relate specifically to the temporomandibular joint. Table XVI gives the mean number of TMJ cases treated per respondent in 1989 (17.88). Table XVII compares the number and percentage of respondents who treat more, the same, or fearer patients than 5 years ago, and Table XVIII lists the respondents choices as to the main cause of temporomandibular disorder (TMD) (79.6% believe that the cause is multifactorial). Table XIX compares the current use of diagnostic aids with their use 5 years ago. It is clear that there has been a major increase in the use of diagnostic aids specifically orientated toward the temporomandibular joint. TMJ palpation, range of motion records, and TMJ
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AnzericanJournalof OrthodonticsantiDentofacialOrthopedics February1993
Table IX. Functional appliance most commonly used by respondents
Appliance
Number of users
Activator Bionator Frankel 2 Sagittal Herbst Other
112 353 107 88 62 75
I
Table Xl. Respondents opinion of
functional appliances
Respondents
Percentage Opinion 16.6 51.2 15.9 12.8 9.2 I1.1
Table • Desirability of including instruction in
the use of functional appliances in formal specialist training
Respondents Opinion Definitely desirable Of moderate benefit Unnecessary An interest to be pursued in continuing education courses
Number 539 . : . 212 "'" 18 32
[ Percentage 67.3 26.5 2.2 4.0
Valid responses: 801.
auscultation all show significant increases. Every radiographic technique that is used in TMJ diagnosis shows an increase in use over the last 5 years. Table XX reports the opinions of respondents on a potential link between premolar extraction and subsequent development of TMD. The possibility of such a development occurring routinely is overwhelmingly rejected by 98.5% of respondents. Two in three believe that it .may occasionally occur, whereas one in three believes that it never occurs. Table XXI reports on the use of second molar extraction as an alternative to premolar extraction. This alternative is rarely or never chosen by respondents. Table XXII reports the number and percentage of respondents who practice more defensively now than 5 years ago (four bf five orthodontists), whereas Table XXIII details how those respondents practice more defensively. " , Table XXIV gives the number and percentage of respondents who report that they are influenced to extract fewer teeth than 5 years ago by a combination of TMJ concerns, medicolegal concerns, or as a defensive measure, 26.4% (just Over one in four of all respondents) are so influenced. Table XXV is a cross-tabulation of those who are
A definite alternative to fixed treatment An occasionally useful adjunct to fixed treatment A frequently useful adjunct to fixed treatment A treatment modality of little proven value. Inherently inferior to fixed appliance therapy
Number
I
Perceniage
6
0.8
491
61.6
195
24.4
105
13.2
Vali d responses: 797.
Table Xll. Use of headgear for Class II molar correction
Respondents
Frequency of use
Nttmber
Percentage
Routinely Occasionally Rarely Never
470 244 60 35
58.1 30.2 7.4 4.3
Valid responses: 809.
influenced to extract fewer teeth than 5 years ago for either TMJ concerns, medicolegal concerns, or as a defensive measure and those who responded to the question of premolar extraction as a possible contributory cause of TMD. A little more than l in 20 orthodontists are influenced to extract fewer teeth for the above reasons even though they believe that premolar extraction and subsequent incisor retraction n e v e r cause TMD. -" Cross-tabulation of respondents by age reveals the following: practitioners in practice more than 20 years are far more likely to provide Begg or standard edg ewise therapy and less likely to provide preadjusted edgewise than their younger colleagues (0 to 20 years in practice).Regarding the use of functional appliances the position is varied with no strong between-gr0up differences emerging.-There is a trend (which misses significance) for younger practitioners in the 0 to 5year group to extract fewer teeth than their older counterparts with the range varying from 25.81% by those
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American Journal of Orthodontics and Dentofacial Orthopedics Volume 103, No. 2
Table Xlll. Number and percentage o f respondents who extract more, the same, or fewer teeth than 5 years ago
Respondents
Amount
Table XVI. Mean number and range o f TMJ patients treated in 1989
glean number. Range
17.88 0-250
of extraction
Number
[
Percentage
More teeth The same Fewer teeth
25
3.1
344 433
42.9 54.0
Valid responses: 802.
Percentage Present mean' extraction rate Mean extraction of respondents 5 )'ears ago Difference Percentage drop in extraction rate in last 5 years
29.28 37.74 "ii 8.46 . -22.41
Valid responses for present extraction rate: 800. Valid responses for.extraction rate 5 )'ears ago: 794. t value: -20.64: two-tail probability: 0.000.
Table XV. Reason for extracting fewer teeth than 5 years ago
Improved facial esthetics TMJ concerns Medicolegal
Number of respondents
Percentageof entire sample
299
36.7
122 80
14.9 9.8
73 147
8.9 17.9
concerns
Greater stability Other
Table XVII. Number and percentage of respondents who treat more, the same, or fewer TMJ patienis than 5 years ago
TMJ patients treated
Table • Present extraction rate (%) of respondents compared with their extraction rate 5 years ago
Reason
Valid responses: 632.
in practice 0 to 5 years to 31.09% by those in practice more than 20 years. Regional analysis reveals tlae following: Begg treatment is significantly more popular in the Middle Atlantic and the Northeast than other regions. Siandard edgewise use shows no regional variation, whereas preadjusted edgewise shows significant regional variation, being most popu!ar in the Southwestern region (82.9%) and least in the Great Lakes region (61.7%). No significant regional differences emerge with regard to use o f functional appliances or rate of extraction.
grote The same Fewer
Respondents Number
I
Percent.age
354 297 82
48.3 40.5 11.2
Valid responses: 733.
Table XVIII. Opinion as to chief cause o f TMJ symptoms
Respondents Chief cause
Number
Stress Occlusion Muscular dysfunction Multifactorial Other
110 23 15 642 17
[ I
Percentage 13.6 2.9 1.9 79.6 2.1
Valid responses: 807.
DISCUSSION The objective o f this study Was to assemble data on a wide range of issues that would help to give a Clearer picture of current trends in orthodontics. For this purpose, a questionnaire was designed and mailed to 1400 orthodontists listed as active members in the 1989 issue of the AAO Directory of members. The use o f a questionnaire has both advantages and disadvantages. Advantages include 9 efficiency in measuring simple ch~/~,~cteristics o f large populations, access to special interest groups with high concern for the subject matter, relatively low cost, and freedom from :possible interview bias as th~ questionnaire is being completed. ~Major disadvantages are the potential for an inadequate response rate and nonresponse bias. With a return rate o f 58.14%, the present study exceeds that of most questionnaires. Other limitations o f a questionnaire study include the impossibility o f determining whether respondents were entirely accurate, and also
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AmericanJournalof Orthodonticsand DentofacialOrthopedics February1993
Table XlX. Current use of diagnostic aids by respondents as compared with 5 years ago
(% of total response)
Respondent usage (%)
,.,ore
Diagnostic aid Study models Extraoral photographs Intraoral photographs Periapicals (FMX) Panoramic radiographs Cephalometric x-ray films Transcranial x-ray films Tomographic x-ray films Computed tomography Arthrography MRI Wrist x-ray films ROM records TMJ palpation Auscultation EMG
,esomel'-es,
3.6 3.7 4.2 5.9 10. I 4.8 10.9 19.0 5.7 6.6 12.4 3.9 26.2 46.7 18.6 2.2
88.0 85.6 79.9 44.8 78.3 79.9 7.1 8.6 3.9 4.8 2.3 18.6 12.8 35.7 13.3 3.2
IRore'
0.9 1.8 2.6 7.9 0.7 1.7 2.6 2.0 1.2 2.0 0.5 6.3 1.2 0.5 1.6 0.2
,,.,elooo',,,,e 0. ! 1.0 2.5 16.7 0.7 1.7 19.3 21.3 16.0 19.3 16.2 18.7 8.4 3.6 12.2 7. I
0.1 0.4 2.1 13.0 1.6 3.8 48.8 38.6 60.7 55.0 55.2 42.3 39.7 4.3 43.2 73. l
-f.
Table •
Premolar extraction and subsequent maxillary incisor retraction as a possible contributory cause of TMD
Opinion Routine cause May occasionally cause Never causes
[Number
I
Percentage
12 496
1.5 62.4
287
36.1
Table XXl. Use of second molar extraction as
an alternative to premolar extraction
Respondents Frequency of use
Number
Routinely Occasionally Rarely Never
15 142 265 388
I
Percentage 1.9 17.5 32.7 47.9
Valid responses: 795. Valid responses: 810.
the subjective nature of some responses (for example, routinely versus occasionally). Notwithstanding the disadvantages of questionnaire use, it is a widely used method of gathering information, and the nature and distribution of a population may lend itself to no better method of research. Discussion of the results centers on the following issues. Current use of fixed appliance therapy
This survey confirms the preadjusted edgewise mechanism as theappliance of choice of the substantial majority 0f orthodontic specialists..lts use is not without drawbacks, perhaps the most serious being the claim of unwanted anchorage loss, 2-~ possibly leading to a fuller facial profile than might be desirable, especially in nonextraction cases. However, despite these criticisms, it seems clear that the popularity of the preadjusted appliance is set to continue and, considering the age demographics noted in this study, its use may possibly increase.
Current use of functional appliances
The results of this stud2r indicate that the extent of use of functional appliances has remained somewhat static in the last 5 years, after a period of rapid growt h in the 5 years previous to that. Itis clear that significant differences exist among orthodontists regarding their use, with about equal numbers rarely or neyer using them compared with those who routinely use them. Such e-vidence that does exist would seem to indicate that functional appliances, when they are successful, produce results that are quite similar, both quantitatively and qualitatively to fixed appliances in an anteroposterior plane. 4 As Bishara and Ziaja ~ point out, while functional appliances may be one of many effective ways of treating a Class II malocclusion, a second period of fixed appliance therapy is usually necessary to ensure proper alignment and interdigitation of the dentition. Certainly, the suggestion that functional appli-
AmericanJournal of Orthodonticsand DentofacialOrthopedics Volume 103, No. 2 Table XXII. Practice more defensively now than 5 years ago
I
Respondents
Response
Number
Yes No
670 138
I
Percentage 82.9 17.1
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Table XXIV. Number and percentage of respondents who extract fewer teeth than 5 years ago and whose decision is influenced by either TMJ concerns, medicolegal concerns, or as a defensive measure
I Decision Extraction of fewer teeth
Valid responses: 808
169
Number of respondents 215
l
Pcrcentageof entire sample 26.4
Valid responses: 814
Table XXlll. Method of practicing more defensively
I Method
Number of respondents
Percentageof entire sample
423
52.0
545
67.0
440
54.1
188 487
.. 23.1 59.8
9 242
1. ! 29.7
39
6.3
More detailed record-taking More careful rccord-keeping More detailed consent form Fewer extractions Better patient communication More extractions More careful patient selection Other
ances offer a definite or better alternative to fixed appliances is overwhelmingly rejected by respondents to this survey. It is clear that a substantial pool of patients treated with functional appliances is now available for retrospective assessment, presumably with the same level of documentation that has accompanied fixed appliance therapy in the United States. Such assessment appears mandatory if the role of functional appliances in orthodontic therapy, their place in postgraduate education, and the design, selection, and use of appliances best fitted to that role are to be adequately defined. Current use of extraction
One of the most important objectives of this study was tO help clarify the present position regarding the use of extraction. Analysis of'the data reveals that the use of extraction has declined considerably with more than half the respondents now extracting fewer teeth than they did 5 years ago. The reported extraction rate has declined from a mean of 37.74% 5 years ago to 29.28% today, representing a percentage drop of 22.41%. (Previously reported surveys of orthodontic specialists gave extraction rates of 34.9% 6 and 39.0%, 7 respectively.)
Table • Cross-tabulation of premolar extraction and subsequent incisor retraction as a possible cause of TMD with extraction of fewer teeth than 5 years ago for either TMJ concerns, medicolegal concerns, or as a defensive measure
Extract fewer teeth for TMD medicolegal or defensive reasons Believe that premolar extraction may be linked to TMD Routinely Occasionally Never
Number
Percentage of total respondents
6 156 47
0.8 19.7 5.9
X2 = 30.1095. d f = 2. Significance 0.0000.
The validity of using reported extraction rates to estimate overall extraction rate has been questioned. 7 Overall, it is certain that any method of determining extraction rate will be imprecise. However, an overall trend should be detectable, especially if the respon- 9 dent's individual reported rates are compared with their reported rate from the recent past (in this case 5 years). Analysis of why orthodontists extract fewer teeth allows some quantification of ihe impact of TMJ concems or medicolegal implications thereof. 26.4% (or a little more than one in four orthodontists) report that their decision to extract fewer teeth than 5 years ago was influenced by a combination of TMJ concerns, medicolegal concerns, or as a deferisive measure. Although a routine causative link between premolar extraction and subsequent development of TMD is overwhelmingly rejected, a majority of respondents believe that such a link may occasionally exist. It should be noted that there is little or no evidence, beyond anecdotal conjecture, to link premolar extraction and TMD.
"170 O ' C o n n o r
On the contrary, several retrospective studies, for example, Sadowsky and Begole, 8 Janson and Hasund, 9 Sadowsky and Poison, ~~consistently fail to demonstrate a causative link between orthodontic treatment (including premolar extraction) and T M D . The impact of this "occasional" belief in the deleterious effect o f extraction is substantial, with 19.7% of orthodontists subscribing to it sufficiently to decrease their extraction rate. Clear evidence of intimidation may be interpreted from the finding that a further 5.9% (approximately 1 in 20) orthodontists are influenced to extract fewer teeth for TMJ or medicolegal concerns even though they believe that premolar extraction and subsequent incisor retraction n e v e r cause TMD. CONCLUSIONS
1. This study shows that claims that the extraction o f teeth may be deleterious to the health o f the temporomandibular joint have had a substantial impact on the rate o f extraction. This is despite the fact that little or no evidence, beyond anecdotal conjecture, exists to support these claims and.:that several retrospective studies have consistently failed to demonstrate such a link. 2. Fixed appliance therapy is the therapy o f choice o f the overwhelming majority of orthodontists. The benefits and role in orthodontics of functional appliance therapy is considerably less defined. 3. Significant differences are evident in the specialty's approach to a wide range Of issues. These differences may reflect training experience, postgraduate experience, age, or regional disharmony, and are not necessarily contradictory. 4. The role o f the orthodontic specialist in the community is dependent on his presenting rigorous intellectual and clinical justification, both to his nonspe-
American Journal of Orthodontics and Dentofacial Orthopedics February 1993
cialist colleagues and to the public at largel as to his particular fitness to be the primary source o f orthodontic care. Treatment modalities should be determined by research, not by legal fears or unsubstantiated allegation.
REFERENCES 1. Baekstrom CH, Hursh-Cesar G. Survey Research. New York: John Wiley & Sons, 1981. 2. Magness WB. The straight-wire concept. AM J ORTttOD 1978;73:541-50. 3. Creekmore TD. JCO interviews Dr. Thomas D. Creekmore on torque. J Clin Orthod 1979;13:305-10. 4. Johnston LE Jr. A comparative analysis of Class II treatments. In: MeNamara JA Jr, Carlson DS, Vig PS Ribbens KA, eds. Science and clinical judgement in orthodontics. Monograph No. 18, Craniofacial Grovdh Series. Ann Arbor: Center for tluman Growth and Development, The University of Michigan, 1986. 5. Bishara SE, Ziaga RR. Functional appliances: a review. AM J ORTnOD DENTOFACORTtlOP 1989;95:250-8. 6. Gottlieb EL, Nelson AH, Vogels DS. 1986 JCO study of orthodontic diagnosis and treatment procedures. Part 1. Overall results. J Clin Orthod 1986;20:612-25. 7. Weintraub JA, Vig PS, Brown C, Kowalski CJ. The prevalence of orthodontic extractions. AM J ORTHOD DFM'rOFACORTIIOP 1989;96:462-6.
8. SadowskyC, BeGole E. Long-term statusoftemporomandibular function and functional occlusion after orthodontic treatment. A.',t J OR'ntOD 1980;78:201-12. 9. Janson M, ttasund A. Functional problems in orthodontic patients out of retention. Eur J Orthod 1981;3:!73-9. 10. Sadowsky C, Polson ANt. Temporomandibular disorders and functional occlusion after orthodontic treatment: results of two long-term studies. Ar,i J ORTHOD1984;86:386-90. Reprint requests to:
Dr. Brian O'Connor Charlemont Clinic Charlemont Mall Dublin 2 Ireland
Contemporary trends in orthodontic practice: A national survey Brian M. P. O'Connor, BDS, MS Dublin, Ireland This study involved the development of a questionnaire to elicit information about current trends in orthodontic practice compared with trends of 5 years ago, The subjects addressed included the use of fixed appliances, functional appliances, extraction therapy, orthodontics and the temporomandibular joint, current diagnostic aids, and medicolegal implications of orthodontic treatment. The questionnaire was mailed to 1400 orthodontic specialists who were randomly selected from across the United States. There were 814 questionnaires returned, representing a 58.14% response rate. The major results of this survey are as follows: (1) The reported extraction rate has declined from a mean of 37.74% 5 years ago to 29.28% today. (2) TMJ concerns (or medicolegal implications thereof) have had a considerable impact in this decline, with 26.4% of orthodontists being influenced, to some extent, to extract fewer teeth because of this factor. (3) The use of functional appliances has remained somewhat static over the last 5 years, after a period of rapid growth in the 5 years previous to that. (4) The preadjusted edgewise appliance is by far the most popular fixed appliance in tJse today, being chosen by 72.6% of respondents. Analysis of the overall results lead to the following conclusions: (1) Fixed appliance therapy is the therapy of choice of the overwhelming majority of orthodontists. The use, benefits, and role in orthodontics of functional appliance therapy is considerably less defined. (2) Treatment modalities, notably on the use of extraction and its relationship to the health of the temporomandibular joint, should be determined by research, not by legal fears or unsubstantiated allegation. (AMJ ORTHOODENTOFAC ORTHOP 1993;103:163-70.)
Factual information relating to changing trends in orthodontics is somewhat sparse. To avoid a fruitless repetition of past mistakes, it is important that any learned specialty document the various ebbs and flows of its progress. An individual member of that specialty should be able to make a considered judgment, not least on an historic basis, as to the efficacy of a particular appliance or concept of treatment that is offered to him. Is the appliance or concept new? How has it been tested? Is it accepted widely by his peers? At a time when the individual practitioner is confronted by a plethora of miracle devices, each promising to deliver the Holy Grail of orthodontic success, the present day orthodontist needs as much factual information as possible. In this context the present study was undertaken. Three main objectives were identified: (1) to assemble and document data on current trends in orthodontic practice, (2) to compare these trends with
Based on a thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry, Department of Orthodontics, St. Louis University. Copyright 9 1993 by the American AssoCiation of Orthodontists. 0889-5406193151.00 + 0.10 811131352
those of 5 years ago, and (3) to analyze the underlying reasons for any changes that might have occurred. The subjects addressed included the use of fixed appliance therapy, functional appliance therapy, extraction therapy, orthodontics and the temporomandibular joint (TMJ), current diagnostic aids, and medicolegal implications of orthodontic treatment.
MATERIALS AND METHODS A questionnaire was developed to elicit information about current trends in orthodontic practice compared with trends of 5 years ago. The questionnaire was mailed to 1400 active orthodontic specialists selected at random from the 1989 Director 5' o f Members o f the American Association o f Orthodontists. The sample ~vas regionally distributed, and the num-
ber sampled represents approximately 1 in 5 (20.68%) of the entire active AAO membership of the United States. The questionnaires were mailed in November 1989, and those returned by January 31, 1990, were accepted for the study. Special mention was made of the assurance of anonymity, and that it was unnecessary to sign the completed questionnaire. The questionnaire was four pages in length and consisted of 29 questions. In addition to asking the age, year of graduation, and state in which they practiced, each respondent was asked about the type of fixed orthodontic training they
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American Journal of Orthodontics and Dentofacial O,rthopedics February 1993
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Table I. Number and percentage of respondents from each age group
Table Ill. Number and percentage of
respondents by region of the United States Region
9Age group O'r)
Number
Percentage
27-40 41-50 51-60 >60
253 322 187 46
31.3 39.9 23.1 5.7
Valid responses to question no. l: 808. glean age: 45.69.
Great Lakes Middle Atlantic Midwestem Northeastern Pacific Coast Rocky Mountain Southern Southwestern
I
Number
I
Percentage
94 69 97 124 146 5! 155 76
I 1.6 8.5 12.0 15.3 17.9 6.3 19.0 9.4
Valid responses to question no. 3:81 I.
Table II. Number and percentage of respondents by years in practice Years in practice 0-5 6-10 11-20 >20
Number 49 168 354 2 3 7 , .:..
Percentage 6. ! 20.8 43.8 29.3
Valid responses to question no. 2: 808. Mean number of years in practice: 16.29.
received and what appliance(s) they currently used; their use and opinion of functional appliances; use of headgear; extraction frequency and rationale of use; etiology of TMJ and treatment; current diagnostic aids, and attitude to defensive practice. Where appropriate, comparisons were made with attitudes on similar topics 5 years ago. Responses on the returned questionnaires were analyzed at the Saint Louis University Medical Center. Data analysis was performed with the Statistical Package for the Social Sciences (SPSS). Descriptive statistics that were compiled included frequencies and means (where appropriate) of responses. Crosstabulations of selected variables (response options) were done, and where indicated, chi-square analyses were performed to determine whether these variables were independent of each other. In the analysis of questions that required quantitative responses, analysis of variance was used. A twotailed t test was used to compare the present extraction rate with that of 5 years ago. In all analyses,statistical significance was judged at the level p < 0.05. RESULTS
Of the 1400 questionnaires mailed to the randomly selected orthodontic specialists, 814 were returned, representing a 58.14% response rate. Data from the 814 returns were consolidated and statistically analyzed. Tables I through XXV depict frequency responses, means (where appropriate) and cross-tabulations. Frequency responses, unless otherwise stated, are given as a percentage of those respondents who replied to a
Table IV. Type of fixed orthodontic training mainly received Respondents Appliance
Number
I
Percentage
Begg Standard edgewise Preadjusted edgewise (straightwire) Johnson twin-wire 9Labial-lingual Lingual Other
183 674 271
22.6 83.1 33.5
61 59 22 31
7.5 7.3 2.7 3.8
particular question (i.e., the valid response) and not as a percentage of the whole sample. As there is some crossover of response to certain questions, with respondents possibly replying to more than one part of a question, percentages will not always total 100%. Practitioners were asked their present age, year of completion of specialist orthodontic training, and the state in which they practiced. Table I describes the number and percentage of respondents by age group (the mean age of respondents was 45.69 years). Table II describes the number and percentage of respondents by years in practice and shows a mean of 16.29 years. Because of the nature of the study the age group 0-5 may b~ underrepresented. Regional response rate is given in Table Ill. Table IV lists the type of fixed orthodontic training mainly received by respondents. Standard edgewise (83.1%) was by far the most common training modem for the sample overall, with preadjusted edgewise (33.5%) and Begg (22.6%) second and third, respectively. However, from Table V, it is clear that preadjusted edgewise (72.6%) is the strong favorite of respondents with standard edgewise (29%) being second, and Begg (5.6%) a remote third. Tables VI through XI are related to questions about
AmericanJournalof Orthodonticsand DentofacialOrthopedics Volume 103, No. 2 V. Type of fixed orthodontic treatment mainly us'ed at present
Table
O' Coltttor "165
Table VII. Use of functional appliances
5 years ago
Respondents
Respondents Appliance
Number
Begg Standard edgewise Preadjusted edgewise Johnson twin-wire Labial-lingual Lingual Other
45 234 588 5 3 6 27
[
Percentage 5.6 29.0 72.6 0.6 0.4 0.7 3.3
Frequency of use
Number
Routinely Occasionally Rarely Never
198 358 133 93
[
Percentage 24.8 44.8 16.5 13.9
Valid responses: 800.
VIII. Use of functional appliances 10 years ago Table
9Table VI. Current use of functional appliances
Respondents Frequency o f Ilse
Number
Routinely Occasionally Rarely Never
200 367 149 93
[
Percentage 24.7 45.4 f. 18.4 11.5
Frequency of use Routinely Occasionally Rarely Never
Respondents [ Number Percentage 66 199 148 250
9.9 30.0 22.4 37.7
Valid responses: 809.
Valid responses: 664.
the use of functional appliances. Table VI shows that they are used routinely by approximately 1 in 4 orthodontists and never by approximately 1 in 10. This Osage is almost identical to that of 5 years ago (Table VII) but markedly different from 10 years ago (Table VIII). At that time, only 1 in 10 orthodontists used functional appliances routinely, whereas 1 in 3 never used them. The bionator was the functional appliance of choice of approximately one in two practitioners who use functional appliances (Table IX), being considerably more popular than any other appliance. The vast majority of respondents believe that in~;truction in the use of functional appliances is desirable in formal specialist training (Table X). The suggestion that functional appliances offer a definite alternative to fixed appliances is overwhelmingly rejected by respondents (Table XI). Rather, functiona ! appliances are viewed as either a frequently usefuladjunct to fixed theratB' (one in four respondents), or an occasionally useful one (one in two respondents). - Table XII shows that the use of headgear as an aid in Class II molar correction is very common, being used either routinely or occasionally by about 9 of every 10 orthodontists. Tables XIII through XV address one of the most important questions in this study, the use of extraction. Table XIII compares current frequency of extraction with 5 years ago, and shows that over half the respon-
dents extract fewer teeth now than they did then, whereas just 3.1% extract more. The extent of the drop is illustrated in Table XIV. From a mean reported extraction rate of 37.74% 5 years ago, the current extraction rate now stands at 29.28%, representing a highly significant drop of 22.41% (Pr = 0.000). The major reasons for the decline in the use of extraction (Table X V ) a r e given as a desire for improved facial esthetics (36.7% of the entire sample), orTMJ concems (14.9% of entire sample), or medicolegal concerns (9.8% of entire sample). Other reasons given by 17.9%. of respondents for extracting fewer teeth included better mechanotherapy, use of brackets versus bands, use of expansion, and use of early treatment. Tables XVI, XVII, and x V I I I relate specifically to the temporomandibular joint. Table XVI gives the mean number of TMJ cases treated per respondent in 1989 (17.88). Table XVII compares the number and percentage of respondents who treat more, the same, or fearer patients than 5 years ago, and Table XVIII lists the respondents choices as to the main cause of temporomandibular disorder (TMD) (79.6% believe that the cause is multifactorial). Table XIX compares the current use of diagnostic aids with their use 5 years ago. It is clear that there has been a major increase in the use of diagnostic aids specifically orientated toward the temporomandibular joint. TMJ palpation, range of motion records, and TMJ
166
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AnzericanJournalof OrthodonticsantiDentofacialOrthopedics February1993
Table IX. Functional appliance most commonly used by respondents
Appliance
Number of users
Activator Bionator Frankel 2 Sagittal Herbst Other
112 353 107 88 62 75
I
Table Xl. Respondents opinion of
functional appliances
Respondents
Percentage Opinion 16.6 51.2 15.9 12.8 9.2 I1.1
Table • Desirability of including instruction in
the use of functional appliances in formal specialist training
Respondents Opinion Definitely desirable Of moderate benefit Unnecessary An interest to be pursued in continuing education courses
Number 539 . : . 212 "'" 18 32
[ Percentage 67.3 26.5 2.2 4.0
Valid responses: 801.
auscultation all show significant increases. Every radiographic technique that is used in TMJ diagnosis shows an increase in use over the last 5 years. Table XX reports the opinions of respondents on a potential link between premolar extraction and subsequent development of TMD. The possibility of such a development occurring routinely is overwhelmingly rejected by 98.5% of respondents. Two in three believe that it .may occasionally occur, whereas one in three believes that it never occurs. Table XXI reports on the use of second molar extraction as an alternative to premolar extraction. This alternative is rarely or never chosen by respondents. Table XXII reports the number and percentage of respondents who practice more defensively now than 5 years ago (four bf five orthodontists), whereas Table XXIII details how those respondents practice more defensively. " , Table XXIV gives the number and percentage of respondents who report that they are influenced to extract fewer teeth than 5 years ago by a combination of TMJ concerns, medicolegal concerns, or as a defensive measure, 26.4% (just Over one in four of all respondents) are so influenced. Table XXV is a cross-tabulation of those who are
A definite alternative to fixed treatment An occasionally useful adjunct to fixed treatment A frequently useful adjunct to fixed treatment A treatment modality of little proven value. Inherently inferior to fixed appliance therapy
Number
I
Perceniage
6
0.8
491
61.6
195
24.4
105
13.2
Vali d responses: 797.
Table Xll. Use of headgear for Class II molar correction
Respondents
Frequency of use
Nttmber
Percentage
Routinely Occasionally Rarely Never
470 244 60 35
58.1 30.2 7.4 4.3
Valid responses: 809.
influenced to extract fewer teeth than 5 years ago for either TMJ concerns, medicolegal concerns, or as a defensive measure and those who responded to the question of premolar extraction as a possible contributory cause of TMD. A little more than l in 20 orthodontists are influenced to extract fewer teeth for the above reasons even though they believe that premolar extraction and subsequent incisor retraction n e v e r cause TMD. -" Cross-tabulation of respondents by age reveals the following: practitioners in practice more than 20 years are far more likely to provide Begg or standard edg ewise therapy and less likely to provide preadjusted edgewise than their younger colleagues (0 to 20 years in practice).Regarding the use of functional appliances the position is varied with no strong between-gr0up differences emerging.-There is a trend (which misses significance) for younger practitioners in the 0 to 5year group to extract fewer teeth than their older counterparts with the range varying from 25.81% by those
O'Connor 167
American Journal of Orthodontics and Dentofacial Orthopedics Volume 103, No. 2
Table Xlll. Number and percentage o f respondents who extract more, the same, or fewer teeth than 5 years ago
Respondents
Amount
Table XVI. Mean number and range o f TMJ patients treated in 1989
glean number. Range
17.88 0-250
of extraction
Number
[
Percentage
More teeth The same Fewer teeth
25
3.1
344 433
42.9 54.0
Valid responses: 802.
Percentage Present mean' extraction rate Mean extraction of respondents 5 )'ears ago Difference Percentage drop in extraction rate in last 5 years
29.28 37.74 "ii 8.46 . -22.41
Valid responses for present extraction rate: 800. Valid responses for.extraction rate 5 )'ears ago: 794. t value: -20.64: two-tail probability: 0.000.
Table XV. Reason for extracting fewer teeth than 5 years ago
Improved facial esthetics TMJ concerns Medicolegal
Number of respondents
Percentageof entire sample
299
36.7
122 80
14.9 9.8
73 147
8.9 17.9
concerns
Greater stability Other
Table XVII. Number and percentage of respondents who treat more, the same, or fewer TMJ patienis than 5 years ago
TMJ patients treated
Table • Present extraction rate (%) of respondents compared with their extraction rate 5 years ago
Reason
Valid responses: 632.
in practice 0 to 5 years to 31.09% by those in practice more than 20 years. Regional analysis reveals tlae following: Begg treatment is significantly more popular in the Middle Atlantic and the Northeast than other regions. Siandard edgewise use shows no regional variation, whereas preadjusted edgewise shows significant regional variation, being most popu!ar in the Southwestern region (82.9%) and least in the Great Lakes region (61.7%). No significant regional differences emerge with regard to use o f functional appliances or rate of extraction.
grote The same Fewer
Respondents Number
I
Percent.age
354 297 82
48.3 40.5 11.2
Valid responses: 733.
Table XVIII. Opinion as to chief cause o f TMJ symptoms
Respondents Chief cause
Number
Stress Occlusion Muscular dysfunction Multifactorial Other
110 23 15 642 17
[ I
Percentage 13.6 2.9 1.9 79.6 2.1
Valid responses: 807.
DISCUSSION The objective o f this study Was to assemble data on a wide range of issues that would help to give a Clearer picture of current trends in orthodontics. For this purpose, a questionnaire was designed and mailed to 1400 orthodontists listed as active members in the 1989 issue of the AAO Directory of members. The use o f a questionnaire has both advantages and disadvantages. Advantages include 9 efficiency in measuring simple ch~/~,~cteristics o f large populations, access to special interest groups with high concern for the subject matter, relatively low cost, and freedom from :possible interview bias as th~ questionnaire is being completed. ~Major disadvantages are the potential for an inadequate response rate and nonresponse bias. With a return rate o f 58.14%, the present study exceeds that of most questionnaires. Other limitations o f a questionnaire study include the impossibility o f determining whether respondents were entirely accurate, and also
168
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AmericanJournalof Orthodonticsand DentofacialOrthopedics February1993
Table XlX. Current use of diagnostic aids by respondents as compared with 5 years ago
(% of total response)
Respondent usage (%)
,.,ore
Diagnostic aid Study models Extraoral photographs Intraoral photographs Periapicals (FMX) Panoramic radiographs Cephalometric x-ray films Transcranial x-ray films Tomographic x-ray films Computed tomography Arthrography MRI Wrist x-ray films ROM records TMJ palpation Auscultation EMG
,esomel'-es,
3.6 3.7 4.2 5.9 10. I 4.8 10.9 19.0 5.7 6.6 12.4 3.9 26.2 46.7 18.6 2.2
88.0 85.6 79.9 44.8 78.3 79.9 7.1 8.6 3.9 4.8 2.3 18.6 12.8 35.7 13.3 3.2
IRore'
0.9 1.8 2.6 7.9 0.7 1.7 2.6 2.0 1.2 2.0 0.5 6.3 1.2 0.5 1.6 0.2
,,.,elooo',,,,e 0. ! 1.0 2.5 16.7 0.7 1.7 19.3 21.3 16.0 19.3 16.2 18.7 8.4 3.6 12.2 7. I
0.1 0.4 2.1 13.0 1.6 3.8 48.8 38.6 60.7 55.0 55.2 42.3 39.7 4.3 43.2 73. l
-f.
Table •
Premolar extraction and subsequent maxillary incisor retraction as a possible contributory cause of TMD
Opinion Routine cause May occasionally cause Never causes
[Number
I
Percentage
12 496
1.5 62.4
287
36.1
Table XXl. Use of second molar extraction as
an alternative to premolar extraction
Respondents Frequency of use
Number
Routinely Occasionally Rarely Never
15 142 265 388
I
Percentage 1.9 17.5 32.7 47.9
Valid responses: 795. Valid responses: 810.
the subjective nature of some responses (for example, routinely versus occasionally). Notwithstanding the disadvantages of questionnaire use, it is a widely used method of gathering information, and the nature and distribution of a population may lend itself to no better method of research. Discussion of the results centers on the following issues. Current use of fixed appliance therapy
This survey confirms the preadjusted edgewise mechanism as theappliance of choice of the substantial majority 0f orthodontic specialists..lts use is not without drawbacks, perhaps the most serious being the claim of unwanted anchorage loss, 2-~ possibly leading to a fuller facial profile than might be desirable, especially in nonextraction cases. However, despite these criticisms, it seems clear that the popularity of the preadjusted appliance is set to continue and, considering the age demographics noted in this study, its use may possibly increase.
Current use of functional appliances
The results of this stud2r indicate that the extent of use of functional appliances has remained somewhat static in the last 5 years, after a period of rapid growt h in the 5 years previous to that. Itis clear that significant differences exist among orthodontists regarding their use, with about equal numbers rarely or neyer using them compared with those who routinely use them. Such e-vidence that does exist would seem to indicate that functional appliances, when they are successful, produce results that are quite similar, both quantitatively and qualitatively to fixed appliances in an anteroposterior plane. 4 As Bishara and Ziaja ~ point out, while functional appliances may be one of many effective ways of treating a Class II malocclusion, a second period of fixed appliance therapy is usually necessary to ensure proper alignment and interdigitation of the dentition. Certainly, the suggestion that functional appli-
AmericanJournal of Orthodonticsand DentofacialOrthopedics Volume 103, No. 2 Table XXII. Practice more defensively now than 5 years ago
I
Respondents
Response
Number
Yes No
670 138
I
Percentage 82.9 17.1
O'Conttor
Table XXIV. Number and percentage of respondents who extract fewer teeth than 5 years ago and whose decision is influenced by either TMJ concerns, medicolegal concerns, or as a defensive measure
I Decision Extraction of fewer teeth
Valid responses: 808
169
Number of respondents 215
l
Pcrcentageof entire sample 26.4
Valid responses: 814
Table XXlll. Method of practicing more defensively
I Method
Number of respondents
Percentageof entire sample
423
52.0
545
67.0
440
54.1
188 487
.. 23.1 59.8
9 242
1. ! 29.7
39
6.3
More detailed record-taking More careful rccord-keeping More detailed consent form Fewer extractions Better patient communication More extractions More careful patient selection Other
ances offer a definite or better alternative to fixed appliances is overwhelmingly rejected by respondents to this survey. It is clear that a substantial pool of patients treated with functional appliances is now available for retrospective assessment, presumably with the same level of documentation that has accompanied fixed appliance therapy in the United States. Such assessment appears mandatory if the role of functional appliances in orthodontic therapy, their place in postgraduate education, and the design, selection, and use of appliances best fitted to that role are to be adequately defined. Current use of extraction
One of the most important objectives of this study was tO help clarify the present position regarding the use of extraction. Analysis of'the data reveals that the use of extraction has declined considerably with more than half the respondents now extracting fewer teeth than they did 5 years ago. The reported extraction rate has declined from a mean of 37.74% 5 years ago to 29.28% today, representing a percentage drop of 22.41%. (Previously reported surveys of orthodontic specialists gave extraction rates of 34.9% 6 and 39.0%, 7 respectively.)
Table • Cross-tabulation of premolar extraction and subsequent incisor retraction as a possible cause of TMD with extraction of fewer teeth than 5 years ago for either TMJ concerns, medicolegal concerns, or as a defensive measure
Extract fewer teeth for TMD medicolegal or defensive reasons Believe that premolar extraction may be linked to TMD Routinely Occasionally Never
Number
Percentage of total respondents
6 156 47
0.8 19.7 5.9
X2 = 30.1095. d f = 2. Significance 0.0000.
The validity of using reported extraction rates to estimate overall extraction rate has been questioned. 7 Overall, it is certain that any method of determining extraction rate will be imprecise. However, an overall trend should be detectable, especially if the respon- 9 dent's individual reported rates are compared with their reported rate from the recent past (in this case 5 years). Analysis of why orthodontists extract fewer teeth allows some quantification of ihe impact of TMJ concems or medicolegal implications thereof. 26.4% (or a little more than one in four orthodontists) report that their decision to extract fewer teeth than 5 years ago was influenced by a combination of TMJ concerns, medicolegal concerns, or as a deferisive measure. Although a routine causative link between premolar extraction and subsequent development of TMD is overwhelmingly rejected, a majority of respondents believe that such a link may occasionally exist. It should be noted that there is little or no evidence, beyond anecdotal conjecture, to link premolar extraction and TMD.
"170 O ' C o n n o r
On the contrary, several retrospective studies, for example, Sadowsky and Begole, 8 Janson and Hasund, 9 Sadowsky and Poison, ~~consistently fail to demonstrate a causative link between orthodontic treatment (including premolar extraction) and T M D . The impact of this "occasional" belief in the deleterious effect o f extraction is substantial, with 19.7% of orthodontists subscribing to it sufficiently to decrease their extraction rate. Clear evidence of intimidation may be interpreted from the finding that a further 5.9% (approximately 1 in 20) orthodontists are influenced to extract fewer teeth for TMJ or medicolegal concerns even though they believe that premolar extraction and subsequent incisor retraction n e v e r cause TMD. CONCLUSIONS
1. This study shows that claims that the extraction o f teeth may be deleterious to the health o f the temporomandibular joint have had a substantial impact on the rate o f extraction. This is despite the fact that little or no evidence, beyond anecdotal conjecture, exists to support these claims and.:that several retrospective studies have consistently failed to demonstrate such a link. 2. Fixed appliance therapy is the therapy o f choice o f the overwhelming majority of orthodontists. The benefits and role in orthodontics of functional appliance therapy is considerably less defined. 3. Significant differences are evident in the specialty's approach to a wide range Of issues. These differences may reflect training experience, postgraduate experience, age, or regional disharmony, and are not necessarily contradictory. 4. The role o f the orthodontic specialist in the community is dependent on his presenting rigorous intellectual and clinical justification, both to his nonspe-
American Journal of Orthodontics and Dentofacial Orthopedics February 1993
cialist colleagues and to the public at largel as to his particular fitness to be the primary source o f orthodontic care. Treatment modalities should be determined by research, not by legal fears or unsubstantiated allegation.
REFERENCES 1. Baekstrom CH, Hursh-Cesar G. Survey Research. New York: John Wiley & Sons, 1981. 2. Magness WB. The straight-wire concept. AM J ORTttOD 1978;73:541-50. 3. Creekmore TD. JCO interviews Dr. Thomas D. Creekmore on torque. J Clin Orthod 1979;13:305-10. 4. Johnston LE Jr. A comparative analysis of Class II treatments. In: MeNamara JA Jr, Carlson DS, Vig PS Ribbens KA, eds. Science and clinical judgement in orthodontics. Monograph No. 18, Craniofacial Grovdh Series. Ann Arbor: Center for tluman Growth and Development, The University of Michigan, 1986. 5. Bishara SE, Ziaga RR. Functional appliances: a review. AM J ORTnOD DENTOFACORTtlOP 1989;95:250-8. 6. Gottlieb EL, Nelson AH, Vogels DS. 1986 JCO study of orthodontic diagnosis and treatment procedures. Part 1. Overall results. J Clin Orthod 1986;20:612-25. 7. Weintraub JA, Vig PS, Brown C, Kowalski CJ. The prevalence of orthodontic extractions. AM J ORTHOD DFM'rOFACORTIIOP 1989;96:462-6.
8. SadowskyC, BeGole E. Long-term statusoftemporomandibular function and functional occlusion after orthodontic treatment. A.',t J OR'ntOD 1980;78:201-12. 9. Janson M, ttasund A. Functional problems in orthodontic patients out of retention. Eur J Orthod 1981;3:!73-9. 10. Sadowsky C, Polson ANt. Temporomandibular disorders and functional occlusion after orthodontic treatment: results of two long-term studies. Ar,i J ORTHOD1984;86:386-90. Reprint requests to:
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