Background: The authors were not able to identify any systematic reviews or meta-analysis on the dental or skeletal changes associated with slow maxillary expansion (SME). Therefore, they conducted a study to evaluate skeletal and dental changes after fixed SME treatment in orthodontic patients with constricted arches.
Methods: The authors included in their evaluation clinical trials that assessed skeletal and dental arch changes through measurements on dental casts or cephalometric radiographs. The authors did not consider trials involving surgical or other simultaneous treatment interventions during the active expansion period.
Results: With the help of a health sciences librarian, the authors searched the following electronic databases: PubMed, MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, Evidence Based Medicine Reviews (Cochrane Database of Systematic Reviews, American College of Physicians Journal Club, Database of Abstracts of Reviews of Effects and Cochrane Central Register of Controlled Trials), EMBASE Excerpta Medica, Thomsen's ISI Web of Sciences and LILACS. Eight articles met the initial inclusion criteria. The authors found that a significant deficiency in the studies was the lack of a control group to factor out changes in the dental arch and skeletal structures associated with normal growth.
Conclusions and clinical implications: The authors found only a lower level of evidence. Therefore, they could make no strong conclusions on dental or skeletal changes that occurred after SME treatment. Clinicians need to rely on their clinical experience, experts' opinions and the presented limited evidence concerning SME treatments.