Meta-analysis of immediate changes with rapid maxillary expansion treatment.

BACKGROUND The authors conducted a literature review to evaluate immediate transverse, anteroposterior, and vertical dental and skeletal changes produced by rapid maxillary expansion (RME). TYPES OF STUDIES REVIEWED The authors reviewed clinical trials that assessed immediate dental and/or skeletal changes after RME using cephalometric analysis, model casts or both. No surgical or other simultaneous treatment was accepted during the evaluation period. RESULTS The authors searched electronic databases and found 31 articles that met the initial inclusion criteria. The authors later rejected 12 of these articles because they did not report immediate changes, three because they lacked detailed descriptions of their results and two because of their nonconventional appliance designs. Fourteen articles satisfied th final inclusion criteria; however, they had methodological deficiencies. CLINICAL IMPLICATIONS The greatest changes resulting from RME in the studies analyzed were dental and skeletal transverse changes. Few vertical and anteroposterior immediate changes were statistically significant, though they probably are not clinically important.