Association between Rapid Maxillary Expansion and Nocturnal Enuresis in Children: A Pilot Study for a Randomized Controlled Clinical Trial

Objectives: This pilot study was conducted to test the protocol of a randomized controlled trial evaluating whether rapid maxillary expansion (RME) can relieve nocturnal enuresis (NE) and improve breathing in children, after ruling out a placebo effect, and investigating whether the effects of RME and NE are related to the morphology of the upper airway. Methods: Seventy 6–15-year-old patients with NE were assessed for eligibility (e.g., constricted maxilla). Enrolled subjects were randomized to immediate treatment with RME (Group 1) or to have the same treatment (RME) delayed for at least six weeks (Group 2). Outcomes comprised the number of wet nights per week, the nocturnal urine production, and the scores of a pediatric sleep questionnaire at baseline, after active treatment (Group 1) or delayed treatment (Group 2), and after 3 months’ retention. Cone beam computed tomographies were taken at baseline and after retention. Results: Six patients were randomized: three in each group. In four of six patients, the number of wet nights per week decreased. Moreover, in responders, nocturnal urine production was reduced following RME. Conclusions: This pilot study suggested that RME might reduce the severity of NE and showed that the protocol of this randomized controlled clinical trial was appropriate.