COVER STORY
JADA Continuing Education
Evidence-based orthodontics for the 21st century
MARC ACKERMAN, D.M.D.
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ABSTRACT
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Background. This article examines some of the data-driven advances in clinical orthodontics and how they might influence the decision-making process in the specialty.
Types of Studies Reviewed. Nearly 100 years of orthodontic study has focused on two issues: one-phase versus two-phase treatment of Class II malocclusion and extraction versus nonextraction treatment of arch perimeter deficiencies. The author addresses these issues by presenting data from the first randomized clinical trial in orthodontics and from a survey of the current literature.
Results. The clinical trial involved subjects who had Class II malocclusion. The researchers who conducted the trial found no difference in the quality of the dental occlusion between the children who had early treatment and those who did not, as judged by both an occlusal index (Peer Assessment Rating scores) and the percentages of the subjects with excellent and less-than-optimal outcomes. Early treatment did not reduce the eventual need for orthognathic surgery. In a separate study, a researcher reported that the maxillary arch perimeter could be increased by 3 to 4 millimeters by using rapid palatal expansion, or RPE, providing space for incisor alignment to resolve crowding. The author concluded that any added benefit of RPE treatment in patients without a crossbite might be "challenging to define."
Clinical Implications. The challenge facing orthodontists in the 21st century is the need to integrate the accrued scientific evidence into clinical orthodontic practice.
As dentistry in the 21st century struggles with the philosophical issue of evidence-based practice, the specialty of orthodontics, too, stands at a crossroads. Historically, orthodontics has uncomfortably straddled the fence separating oral health care and elective cosmetology. While societal and cultural mores increasingly have shifted toward facial and anterior tooth esthetics, dentists have continued to view the primary goal of orthodontics as correcting tooth alignment and occlusion. This article examines some of the data-driven advances in clinical orthodontics and how they might influence the decision-making process in that specialty.
The challenge facing orthodontists in the 21st century is the need to integrate the accrued scientific evidence into clinical orthodontic practice.
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DEFINING AND REDEFINING ORTHODONTICS
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The American Association of Orthodontists defines orthodontics, or dentofacial orthopedics, as the area of dentistry concerned with the supervision, guidance and correction of the growing and mature dentofacial structures. This definition includes conditions that require movement of teeth or correction of mal-relationships and malformations of related structures by adjusting relationships between and among teeth and facial bones by applying forces or by stimulating and redirecting the functional forces within the craniofacial complex. Major responsibilities of orthodontic practice include the diagnosis, prevention, interception and treatment of all forms of malocclusion of the teeth and associated alterations in their surrounding structures; the design, application and control of functional and corrective appliances; and the guidance of the dentition and its supporting structures to attain and maintain optimum relations in physiologic and esthetic harmony among facial and cranial structures.1
Although this definition addresses the occlusal, functional and esthetic components of malocclusion, there is no mention of the psychosocial aspect of malocclusion and the role of orthodontics in its treatment. Studies have demonstrated that well-aligned teeth and a pleasing smile afford positive social status, whereas irregular or protruding teeth are attached to negative status.2,3 A "handicapping malocclusion" not only implies a severe structural or functional deviation from the optimal state, but also underscores the psychosocial impact of the perceived dentofacial disharmony.
According to data from the Third National Health and Nutrition Examination Survey, or NHANES III,4 which was conducted between 1989 and 1994, malocclusions falling into categories outside the limit of orthodontic correction alone (severe Skeletal Class II and III) occurred in about 4 percent of the population. By contrast, malocclusions related to severe or extreme incisor irregularity in adolescents and adults existed in about 15 percent of the surveyed population. Hence, it is exceedingly difficult to describe the prevalence of handicapping malocclusion owing to the many occlusal, skeletal, esthetic and psychosocial components involved. Another confounding variable is the disparity that exists between the lay public’s view and the orthodontic specialty’s view of what constitutes a malocclusion in need of treatment.
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MYTHOLOGY REGARDING NEED FOR TREATMENT
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It would appear logical that malocclusion would have a causal relationship with both dental decay and periodontal disease. Theoretically, satisfactory oral hygiene for a maloccluded dentition would be more difficult to achieve than it would with a dentition that boasts an ideal occlusion. Recent data suggest that a person’s willingness and motivation to maintain oral hygiene have a greater impact on the occurrence of dental disease than does tooth alignment.5
Two studies conducted in the late 1970s that examined a large number of orthodontically treated patients 10 to 20 years after treatment provide some insight on long-term relationships between malocclusion and oral health.6,7 In both studies, patients who underwent orthodontic treatment demonstrated a similar periodontal status to that of untreated subjects in the same age group, despite the better functional occlusions of the orthodontically treated group. There was no evidence of a beneficial effect of orthodontic treatment on future periodontal health. Conversely, these long-term studies gave no indication that orthodontic treatment increased the chance of later periodontal manifestations.
Some dentists have suggested that even minor deviations from a canine-protected occlusion will trigger parafunctional habits such as bruxism and clenching. If this indeed were the case, most people’s occlusion would need treatment to prevent symptomatology in the masticatory muscles. Data suggest that because a large portion of the population has moderate malocclusions (roughly 50–75 percent) and this number far exceeds the number of people in the population who have temporomandibular dysfunction (5–30 percent, depending on the symptoms examined), it seems unlikely that occlusal patterns alone are the cause of hyperactivity of the masticatory muscles associated with temporomandibular joint dysfunction.8
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MYTHOLOGY REGARDING TREATMENT OUTCOME
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Nearly 100 years of orthodontic study has focused on the issues of one-phase versus two-phase treatment of Class II malocclusion and extraction versus nonextraction treatment. With greater emphasis on data-driven dental treatment, there is good evidence in the orthodontic literature to put to rest these age-old debates. It would appear that some of the most strongly held orthodontic treatment strategies are severely flawed when viewed in light of efficiency and efficacy.
Proffit9 stated:
In the 1990s, the first randomized clinical trial in orthodontics studied preadolescents with Class II malocclusion versus Class II treatment in adolescents.10 The central question was whether early orthodontic treatment of a patient with a Class II malocclusion was sufficiently more effective than later treatment to justify the longer time in treatment and the greater economic cost. In the clinical trial, which was conducted at the University of North Carolina at Chapel Hill, researchers carried out Phase 2 treatment (comprehensive orthodontic treatment) for untreated control subjects and for subjects who had completed Phase 1 treatment.10 The result was no difference in the quality of dental occlusion between the children who underwent early treatment and those who did not, as judged by both the Peer Assessment Rating index11 and the percentages of the groups with excellent and less-than-optimal outcomes.
All treatment needs to be evaluated from two perspectives. The first is its effectiveness, defined as how well it works, i.e., how successful it is in overcoming the patient’s problems. Since nothing works perfectly all the time and unlikely things occasionally succeed, effectiveness must be considered in terms of the average amount of improvement, or probably better in clinical studies, the proportions of patients with excellent, good, fair, and poor outcomes. Effective treatment produces large average improvement, and a high percentage of the patients have an excellent outcome. The second is efficiency, defined as how much benefit the patient receives relative to the costs and risks of treatment. In this sense, cost is broader than just money. There are also a host of factors—time in treatment, number of patient visits, discomfort or morbidity, emergency appointments to deal with problems—that impact both the patient and the doctor. Efficient treatment produces large benefits with minimal cost (in both senses of the word) and minimal risk.
Another finding in the clinical trial was that early treatment did not reduce the number of children who needed premolar extraction in Phase 2 treatment. The extraction percentages during Phase 2 treatment were almost identical between the groups, regardless of whether they had had Phase 1 treatment. Early treatment did not reduce the eventual need for orthognathic surgery. The Phase 1 treatment generally reduced the length of Phase 2 treatment by roughly 25 percent, although there was great variability. The two phases of treatment took longer than one phase in almost all cases. Proffit9 concluded that preadolescent treatment for most children with Class II malocclusion is no more effective than later treatment, and it is less efficient.
In the past two decades, the orthodontic pendulum has swung toward treatment strategies aimed at avoiding the extraction of permanent teeth in the case of arch perimeter deficiencies.
Rapid palatal expansion.
In the past two decades, the orthodontic pendulum has swung toward treatment strategies aimed at avoiding the extraction of permanent teeth in the case of arch perimeter deficiencies. One of the most visible mechanotherapies has been the use of rapid palatal expansion, or RPE, in the absence of posterior crossbites, to gain arch perimeter and avoid extractions. This treatment, which often is initiated in the mixed dentition, raises some questions related to efficiency and efficacy.
Gianelly,12 in a recent article, raised and answered two important questions. First, with the absence of a posterior crossbite, is RPE necessary to gain the needed arch perimeter to avoid extractions? If yes, then is maxillary arch perimeter the primary determinant in the decision-making process about whether to extract? He stated that the maxillary arch perimeter can be increased by 3 to 4 millimeters, providing space for incisor alignment. Since this has a negligible effect on the perimeter of the mandibular arch, some type of space-gaining procedure must be initiated to prevent Brodie syndrome (maxillary transverse excess and concomitant buccal crossbite) and to resolve mandibular arch perimeter deficiency when needed. It should be pointed out, though, that data indicate that the transverse expansion of the mandibular arch in selected areas is unstable.13
Brennan and Gianelly14 recommended an alternative approach to resolving crowding by simply maintaining arch length during the transitional period of dentitional development. When they preserved the "E" space (the discrepancy between the widths of the primary second molar and the permanent second premolar) in a sample of patients with an average of 4 to 5 mm incisor crowding, they found that 68 percent of the patients had adequate space for alignment, and another 19 percent had adequate space with only marginal arch length increase (up to 1 mm per side).14 In such patients, Brennan and Gianelly found that the maxillary arch could be properly positioned over the mandibular arch without the use of RPE. Gianelly12 concluded that any added benefit of RPE treatment in patients without a crossbite might be "challenging to define." Overall, the decision between extraction and nonextraction for any given patient is multi-factorial. The clinician should view arch perimeter deficiency from the standpoint of a patient’s well-being in functional, esthetic and psychosocial areas.
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COMMUNICATION: PARAMOUNT IN ORTHODONTIC CARE
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A shift that has occurred in the last 15 years of dental practice is the evolution of patient autonomy and informed consent and the departure from paternalism in the decision-making process. A conflict for today’s orthodontist is, on the one hand, to adhere to the obligation set forth in the American Dental Association Principles of Ethics and Code of Professional Conduct15 to perform the highest quality service within his or her power to perform, yet, on the other hand, to observe the patient’s right to decide on which treatment alternative is best suited to his or her needs. The alternative of no treatment always is an option as long as the risks are explained to the patient.
To satisfy the doctrine of informed consent, Chiccone16 recommended discussing the following points with the patient:
- – a diagnosis, presented in language the patient can understand;
- – a comprehensive treatment plan, explaining what procedures are recommended and how they will be performed;
- – an overview of reasonable alternative treatments that are available regardless of who is the clinician who performs them;
- – the probable sequelae of electing not to have treatment;
- – the potential risks, consequences and likelihood of secondary treatment (typically, it is the complication not discussed with the patient that triggers a liability claim);
- – the predicted outcome of treatment including how the patient will benefit and the probability of success. Realistic goal setting should always supersede optimism.
He added that three caveats must be heeded in implementing the doctrine of informed consent:
- – the greater the potential injury—even if the risk is minimal—the greater the obligation to inform the patient (such as the risk of death resulting from anesthesia);
- – the greater the chance of complications occurring—even if the injury would be minimal—the greater the obligation to inform the patient (such as the risk of root resorption);
- – the more elective the proposed treatment, the more invasive the bodily intrusion will be considered in the event of an injury—thus, again, the greater the obligation to inform the patient (for example, orthognathic surgery performed for esthetic reasons).
In the absence of objective criteria, orthodontic treatment—as a mode of promoting a patient’s well-being and enhancing quality of life—is a matter of individual judgment. The orthodontist/dentist must share this judgment with the patient by providing adequate information regarding the risks involved in treatment. Thus, when a patient or a parent asks the dentist whether he or she or his or her child "needs braces," the dentist must in turn frame the question in a wider context. Essentially, the question becomes one of whether some form of orthodontic treatment will improve the patient’s overall well-being and quality of life in the functional, esthetic or psychosocial area (Figure 1
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Figure 1. The decision-making process in clinical orthodontics. Interactive discussion between the patient and orthodontist will help elucidate the patient’s esthetic, functional and psychosocial needs. Ultimately, the orthodontist will describe the risks of treatment and the patient will be able to make an informed decision regarding treatment.
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It has been argued that the orthodontic specialty evolved from a guild model in the early 20th century to a commercial model in the second half of the century.17 In the 21st century, orthodontics needs to move to an interactive model, fulfilling the patient’s esthetic, functional and psychosocial needs by providing treatment that is clinically effective and efficient and that preserves the patient’s autonomy by virtue of the doctrine of informed consent. If dentistry in general and orthodontics in particular do not initiate this change, then it most likely will come from the legal profession.
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THE SCOPE OF CONTEMPORARY ORTHODONTICS
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Contemporary orthodontic practice can be summarized as interactive problem-oriented diagnosis and treatment planning between clinician and patient, with the goal of defining mutually desirable treatment objectives coupled with the selection of the most appropriate mechanotherapy to achieve these ultimate goals (Figure 2). The first key to a successful outcome in orthodontic therapy is to follow a systematized method of clinical examination and data collection, which should aid in eliciting the patient’s chief concerns and dento-facial presentation in the four dimensions of the sagittal aspect, the vertical aspect, the transverse aspect and time. Computer imaging has become a tremendously useful communication tool for both the patient and orthodontist in describing dento-facial discrepancies.
Once a diagnostic problem list has been determined, the clinician and the patient should rank each problem in terms of its therapeutic modifiability and its importance to the patient’s esthetic, functional and psychosocial needs. The term "therapeutic modifiability"18 refers to the clinician’s ability to predict the "achievable optimum" for a given patient when attempting to satisfy treatment objectives with a given treatment modality. The greater the effort needed to produce a small improvement in a malocclusion, the lesser the therapeutic modifiability, and vice versa. The clinician and patient must weigh each problem against its therapeutic modifiability so that the clinician can synthesize and initiate a final treatment plan.
At the completion of orthodontic treatment, the clinician removes the orthodontic appliances and the retention phase begins. Traditionally, the orthodontist has served in a supervisory role during this phase; today, however, the orthodontist should take more of an advisory role. If the orthodontist clearly explained the potential risks of relapse before the initiation of treatment, then the onus of following the prescribed retention at the completion of treatment should come as no surprise to the patient. The orthodontist should reiterate the potential manifestations of orthodontic relapse and provide anticipatory guidance in how to prevent them. Lastly, adolescent patients should be advised as to the status of their third molars at the completion of treatment, and the appropriate recommendations should be made in concert with their general dentist.
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CONCLUSION: THE FUTURE
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It is conceivable in 2004 that if a patient seeks orthodontic opinions from 10 orthodontists, he or she may receive 10 different treatment plans. It also is conceivable that all 10 treatment plans could achieve satisfactory results. However, when viewed in light of the principles of effectiveness and efficiency, there might be only one or two treatment alternatives that best satisfy the patient’s esthetic, functional and psychosocial needs. The challenge facing orthodontists in the 21st century is the need to integrate the accrued scientific evidence into clinical orthodontic practice. Until this occurs, orthodontists will not be able to present a forthright and accurate cost/benefit analysis to the patient and, therefore, not obtain truly informed consent.
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Dr. Ackerman is in the private practice of orthodontics at 931 Haverford Road, Bryn Mawr, Pa. 19010, e-mail "Ackersmile{at}aol.com". Address reprint requests to Dr. Ackerman.
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REFERENCES
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- American Association of Orthodontists. Glossary of dentofacial orthopedic terms. St. Louis: American Association of Orthodontists; 1996.
- Shaw WC. The influence of children’s dentofacial appearance on their social attractiveness as judged by peers and lay adults. Am J Orthod 1981;79:399–415.[Medline]
- Shaw WC, Rees G, Dawe M, Charles CR. The influence of dentofa-cial appearance on the social attractiveness of young adults. Am J Orthod 1985;87:21–6.[Medline]
- Proffit WR, Fields HW, Moray LJ. Prevalence of malocclusion and orthodontic treatment need in the United States: estimates from the NHANES III survey. Int J Adult Orthodon Orthognath Surg 1998;13:97–106.[Medline]
- Helm S, Petersen PE. Causal relation between malocclusion and caries. Acta Odontol Scand 1989;47:217–21.[Medline]
- Sadowsky C, BeGole EA. Long-term effects of orthodontic treatment on periodontal health. Am J Orthod 1981;80:156–72.[Medline]
- Polson AM, Subtelny JD, Meitner SW, et al. Long-term periodontal status after orthodontic treatment. Am J Orthod Dentofac Orthop 1988;93(1):51–8.[Medline]
- Greene CS. Etiology of temporomandibular disorders. Semin Orthod 1995;1:222–8.[Medline]
- Proffit WR. Treatment timing: effectiveness and efficiency. In: 28th Annual Moyers Symposium, Vol. 39 (monograph). Ann Arbor, Mich.: The University of Michigan Department of Orthodontics; 2002:13–24.
- Tulloch JF, Phillips C, Proffit WR. Benefit of early Class II treatment: progress report of a two-phase randomized clinical trial. Am J Orthod Dentofacial Orthop 1998;113:62–72.[Medline]
- Richmond S, Shaw WC, Roberts CT, Andrews M. The PAR Index (Peer Assessment Rating): methods to determine outcome of orthodontic treatment in terms of improvement and standards. Eur J Orthod 1992;14(3):180–7.[Abstract/Free Full Text]
- Gianelly AA. Rapid palatal expansion in the absence of crossbites: added value? Am J Orthod Dentofacial Orthop 2003;124:362–5.[Medline]
- Burke SP, Silveira AM, Goldsmith LJ, Yancey JM, Van Stewart A, Scarfe WC. A meta-analysis of mandibular intercanine width in treatment and postretention. Angle Orthod 1998;68:53–60.[Medline]
- Brennan M, Gianelly AA. The use of the lingual arch in the mixed dentition to resolve incisor crowding. Am J Orthod Dentofacial Orthop 2000;117:81–5.[Medline]
- American Dental Association. ADA principles of ethics and code of professional conduct. Chicago: American Dental Association; 2003. Available at: "www.ada.org/prof/prac/law/code/index.asp". Accessed Nov. 26, 2003.
- Chiccone MU. Informed consent: in perspective. The Dental Rx (publication of the Mid-Atlantic Medical Insurance Company) 1990;3(2).
- Ackerman JL. Ethics and risk management in orthodontics. In: Ghafari JG, Moorrees CF, eds. Orthodontics at crossroads: Trends in contemporary orthodontics. Boston: Harvard Society for the Advancement of Orthodontics; 1993:49–60.
- Moorrees CF, Gron AM. Principles of orthodontic diagnosis. Angle Orthod 1966;36:258–62.[Medline]
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ABSTRACT
DEFINING AND REDEFINING...
