Nocturnal enuresis and rapid maxillary expansion : – long-term effect, prognostic variables, respiration during sleep and quality of life

Abstract: Background:The orthodontic technique rapid maxillary expansion (RME) has been reported to have a potentially curative effect on nocturnal enuresis (NE). The mechanism behind this is unknown but could possibly be due to placebo and/or effects on respiration during sleep. Aim: This thesis aims to approach an answer to the following questions, with a randomized, placebo-controlled method: 1) Does rapid maxillary expansion have a curative effect on therapy-resistant NE? 2) Is the potential curative effect due to respiratory events that can be measured during sleep? 3) Do enuretic children have an impaired quality of life (QoL)?  Subjects & Methods: In study I we evaluated the QoL in enuretic children while assessing the test re-test reliability of a Swedish version of an established QoL questionnaire. Study II and IV assess respiration during sleep in children with NE; in study II comparisons are made with healthy control children and in study IV we evaluate the respiratory effects of RME. Study III is a randomized placebo-controlled study investigating whether RME is a useful therapy for NE and if the treatment effect is due to placebo.Results: Study I:The Swedish version of the questionnaire proved to be a reliable tool (Chronbach’s alpha 0.87) with excellent test-retest stability (ICC = 0.762). Enuresis affects the children’s QoL and interactions with peers.Study II:The hypopnea index (HI) and the oxygen desaturation index were both significantly higher in the enuretic children compared to the healthy controls, (p=0.04 and p=0.05) but all values fell within the normal range.Study III:RME resulted in a significant reduction in wet nights i.e. the mean number of wet nights out of 14 was 11.4 before and 9.2 after RME. (p=0.003) This was not observed in the placebo group (p=0.40).Study IV:There was a significant reduction of sleep efficiency during RME. (p=0.001) The mean HI was also affected. (p=0.005)Conclusions: • Children with nocturnal enuresis have an impaired self-esteem and their quality of life is affected in their relationship with friends.• There were no major differences in respiration during sleep between enuretic children and controls.• Rapid maxillary expansion reduces the number of wet nights in children with enuresis, but the effect is of limited clinical value.• The antienuretic effect does not seem to be due to a placebo effect of the appliance.• The majority of the children in our study sample did not have sleep disordered breathing as a co-morbidity to their nocturnal enuresis.