Long-term stability of maxillary and mandibular arch dimensions when using rapid palatal expansion and edgewise mechanotherapy in growing patients.

Objective: The purpose of this study was to assess the long-term stability of rapid palatal expansion (RPE) followed by full fixed edgewise appliances.

Methods: This study included 67 patients treated using Haas-type RPE and non-extraction edgewise appliance therapy at a single orthodontic practice. Serial dental casts were obtained at three different time points: pretreatment (T), after expansion and fixed appliance therapy (T), and at long-term recall (T). The mean duration of the T-T and T-T periods was 4.8 ± 3.5 years and 11.0 ± 5.4 years, respectively. The dental casts were digitized, and the computed measurements were compared with untreated reference data.

Results: The majority of treatment-related increases in the maxillary and mandibular arch measurements were statistically significant ( < 0.05) and greater than expected for the untreated controls. Although many measurements decreased postretention (T-T), the net gains persisted for all of the measurements evaluated.

Conclusions: The use of RPE therapy followed by full fixed edgewise appliances is an effective method for increasing maxillary and mandibular arch width dimensions in growing patients.