Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Daytime sleepiness
RCT Crossover design	20 people (AHI 12–93; see table 2 )	Subjective measures of daytime sleepiness (ESS score; see table 3 ) 2–3 months 6.7 with oral appliance 6.0 with CPAP	Reported as not significant P value not reported		Not significant
Intermediate outcomes
Systematic review	232 people 7 RCTs in this analysis	Change in AHI (see table 2 ) with oral appliance with nasal CPAP Absolute results not reported	change in AHI –7.97 episodes/hour 95% CI –9.56 episodes/hour to –6.38 episodes/hour	Effect size not calculated	nasal CPAP
RCT Crossover design	20 people (AHI 12–93)	Sleep-disordered breathing (AHI) 2–3 months 5.3 with oral appliance 0 with CPAP	Reported as not significant P value not reported		Not significant
Quality of life
Systematic review	128 people 2 RCTs in this analysis	Quality of life (assessed using the Functional Outcomes Sleep Questionnaire; see table 3 ) with oral appliance with nasal CPAP Absolute results not reported	Difference in score –0.18 95% CI –0.42 to +0.07		Not significant