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Clinical question.
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Does contemporary orthodontic therapy affect periodontal health?
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Review methods.
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The authors conducted a comprehensive search of the literature from January 1980 to June 2006, searching eight databases electronically and six dental journals by hand. This search identified 3,552 titles and abstracts, 12 of which were full articles that met the inclusion criteria. The authors included one randomized controlled trial (RCT), three cohort studies and eight cross-sectional studies in which researchers compared untreated patients with patients who underwent contemporary orthodontic treatment and in which the investigators conducted posttreatment evaluations of periodontal health. The authors included studies involving both fixed and removable treatment modalities, but they excluded studies involving full-banded and orthognathic surgery and distraction osteogenesis. The article describes the reasons for this exclusion.
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Main results.
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There was inconclusive evidence to support any positive association between orthodontic therapy and periodontal health. This finding was due to the absence of direct evidence of the positive effects of orthodontic therapy on periodontal health. Some evidence suggests a small mean worsening of periodontal health after orthodontic therapy.
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Conclusion.
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This comprehensive search indicates an absence of reliable evidence for the positive effects of orthodontic therapy on patients’ periodontal status. The existing evidence does not support the claim that orthodontic therapy results in overall improvement in periodontal health.
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COMMENTARY
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Importance and context.
The American Association of Orthodontists (AAO)1 states in its literature that dental alignment achieved with orthodontic therapy facilitates plaque removal and reduces occlusal trauma, which improves management of periodontal health. While this AAO publication suggests that orthodontic therapy may have an indirect effect by allowing better management of periodontal health, on the basis of this systematic review, we find that a direct positive association of orthodontic therapy with periodontal health is yet to be demonstrated.
Strengths and weaknesses of the systematic review.
The review authors used widely accepted methods to identify studies addressing the clinical questions posed. They established no single a priori periodontal outcome measure. The outcomes evaluated included both patient-oriented and disease-related measures. The inclusion and exclusion criteria were explained and reasonable. The authors recognized the review’s limitations: the low number of included studies, a variety of measured outcomes and a high risk of bias.
Strengths and weaknesses of the evidence.
The pool of 12 studies constitutes a weak body of evidence; 11 studies were cohort and cross-sectional and one was an RCT. The studies differed in the kind of periodontal outcomes that were assessed, although there were enough similarities for the investigators to make preliminary conclusions. Overall, the authors of this review found little evidence to support any positive periodontal effects of orthodontic therapy. In fact, they found some evidence of negative periodontal effects of orthodontic therapy.
Implications for dental practice.
Although the existing evidence comes from poorly designed research with a substantial risk of bias, it suggests that orthodontic treatment may slightly increase the risk of developing periodontal disease, including alveolar bone loss, periodontal pocketing and gingival recession. The strongest evidence in establishing a relationship between orthodontic therapy and periodontal conditions is a randomized clinical trial that compared periodontal status among people who had or had not received orthodontic therapy. The authors stated that they included RCTs; however, they included only one, and its relevance as a basis for comparison may be questioned. In it, the treatment lasted only three months, whereas the norm for orthodontic treatment duration is 12 to 18 months. Further research is needed to assess the association between orthodontic therapy and periodontal health.
TOP
Clinical question.
Review methods.
