Long-term Skeletal Changes with Rapid Maxillary Expansion: A Review of the Literature

Evidence-based dentistry is currently a high priority in the clinical practice of orthodontics. Treatment decisions are made using evidence-based information whenever it is available to the clinician. The focus of this article is to evaluate the current literature available on the long-term stability of rapid maxillary expansion. The literature was reviewed from 1979 to 2009, and all systematic reviews and meta-analyses were included in this evaluation. Clinical trials, retrospective or prospective, were also reviewed, even though they did not always meet the inclusion criteria set forth. This review of the literature shows that, based on the evidence provided by 2 trials, there is a lack of strong evidence of the long-term stability of maxillary expansion in adolescent patients with posterior crossbites at the initiation of orthodontic therapy. Factors responsible for this include high attrition rates, lack of adequate control groups, unclear diagnosis and ill-defined study end points, and lack of standardization of studies. The conclusions that can be drawn from our review are as follows: there is a clear need for well-designed and well-controlled retrospective or prospective clinical trials for the evaluation of stability of maxillary expansions. At the present time, orthodontists must accept that some treatment modalities do not yet have a high level of evidence for treatment effectiveness.