Evidence Based Orthodontics

Excerpts from article in Journal of American Dental Association
"Evidence-Based Orthodontics for the 21st Century"
(JADA 135 (2004): 162-167)
Marc Ackerman, D.M.D.

Although this article was written several years ago, it provides excellent, evidence-based research results on a topic about which enormous confusion still exists.

Abstract
Mythology - Treatment Need
Mythology - Treatment Outcome
Communication Is Paramount
Conclusion - The Future

Abstract

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 lessthan- 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.

Mythology Regarding Need For Treatment

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.

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. 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.

Mythology Regarding Treatment Outcome

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.

Proffit stated:

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.

In the 1990s, the first randomized clinical trial in orthodontics studied preadolescents with Class II malocclusion versus Class II treatment in adolescents. 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. 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 index and the percentages of the groups with excellent and less-than-optimal outcomes.

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.

Communication: Paramount In Orthodontic Care

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 Conduct 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, Chiccone 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).

Conclusion: The Future

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.