ONLINE RESOURCE 1. Summary of eligible studies’ demographics, inclusion/exclusion criteria and risk of bias.

Reference / Gender (M/F) and average age of the participants / Inclusion criteria / Exclusion criteria / Results Measuring Technique / Summary of Risk of Bias
Aarab et al, 2011 [35] / Gender completed study:
CPAP: 12/6
MAD: 16/4
Placebo: 14/5
Age:
CPAP: 55.4±9.8
MAD: 50.3±9.1
Placebo: 51.3±10.1 / Age >18 years, and apnea-hypopnea index (AHI) between 5 and 45 events per hour, and a report of excessive daytime sleepiness (Epworth Sleepiness Score 10) or at least two of the symptoms suggested by the American Academy of Sleep Medicine Task Force, e.g. unrefreshing sleep and daytime fatigue. /
  • Medical: Respiratory/sleep disorder other than OSA
  • BMI > 40
  • Medication usage that could influence respiration or sleep Periodic limb movement disorder
  • Previous treatment with CPAP or MAD
  • Reversible morphological upper airway abnormalities (e.g. enlarged tonsils)
  • Other medical conditions, e.g. psychiatric disorders
  • Dental: Temporomandibular disorders
  • Untreated periodontal problems
  • Dental pain
  • Lack of retention possibilities for an oral appliance
/ Baseline PSG and 6 ± 2 months after treatment. / Unclear Risk
Barnes et al, 2004 [24] / Gender:
80% M/20% F
Age: 47.0+ 0.9 years / All subjects had been referred for investigation of symptomatic sleep-disordered breathing. Subjects were middle aged (47.0 ± 0.9 years), predominantly male (80%), and overweight (interquartile range body mass index, 27.8–32.8 kg/m2), with mild to moderate OSA (AHI, 5–30 per hour). / If they did not have at least 2 teeth in their upper and lower jaws on both left and right sides to enable adequate retention of the MAS. If dental caries were found. / Baseline PSG and after each 3 months: neurobehavioral testing, 24-hour BP and echocardiography. / Unclear Risk
Clark et al, 1996 [36] / Gender: 23 M/0F
Age: 47.1+8.07years /
  • Have successfully completed an all-night PSG that demonstrated an OSA disorder.
  • Be between 21 and 75 years of age.
  • Have and AHI score greater than or equal to 15 events per hour of sleep.
  • Have adequate nasal airflow capacity as determined by a clinical examination from a qualified otolaryngologist.
  • Be in good health and willing to be randomly assigned to both treatment conditions.
  • Have at least 7 mm of protrusive jaw movement from a position of maximum intercuspation.
/
  • Exhibit frequent central sleep apnea events (more than two per hour).
  • Present with more than one missing tooth per quadrant, excluding third molars (fixed bridges were not considered missing).
  • Have substantial visual clinical evidence of periodontal disease or dental caries.
  • Have substantial evidence of a temporomandibular joint (TMJ) disorder, including painful or loud noises, restricted mouth opening (<40 mm of interincisal opening), or any site of severe TMJ or muscle tenderness in their masseter and/or temporalis muscles.
  • Use alcohol, narcotics, or psychoactive medications daily.
  • Have serious nasal passage obstruction or allergies that would prevent the use of the CPAP device.
Have previously failed CPAP or dental device treatment for OSA. / Baseline PSG and sleep questionnaires at the end of each 2-week treatment period / High Risk
Dal-Fabbro et al, 2014 [37] / Gender: 24 M/ 5 F
Age: 47.0±8.9 years /
  • Moderate-to-severe OSA (clinical criteria and an apnea and hypopnea index (AHI)20).
  • Either gender
  • Body mass index (BMI) under 35 kg/m2,
  • 25-65 years of age
  • Dentition in good condition
  • Minimum mandibular protrusion of 7 mm
  • AHI of more than 20 was considered to include truly moderate OSA patients according to the variability of the AHI.
/
  • Patients with periodontal disease
  • Severe temporomandibular disorder
  • Other sleep disorders
  • Disturbances that interfere in CPAP use
  • Alcohol or drug abuse
Previous treatment for OSA / PSG, ESS, 24-h ambulatory BP, oxidative stress parameters, and Heart Rate Variability were assessed at baseline and after 1 month of treatment / High Risk
Engleman et al, 2002 [28] / Gender: 39 M/ 12 F
Age: 46±9 years / Patients aged 18–70 years with AHI of 5 or more and two or more symptoms of SAHS, including sleepiness. / Patients with fewer than four teeth remaining in either arch, coexisting narcolepsy or periodic limb movements of more than 10 per hour, major medical illness, shift work, or living more than 50 miles away from Edinburgh / Baseline and 8 weeks: Sleep study, objective lab tests, questionnaires, and portable EEG. / Unclear Risk
Ferguson et al, 1997 [38] / Gender: 19 M/5 F
Age:
44±10.6 years / Patients with symptomatic mild to moderate OSA (AHI 15–55/hour of sleep during diagnostic polysomnography) were recruited for this prospective crossover study. / Patients were unselected apart from a requirement that they had at least 10 teeth in each of the maxillary and mandibular arches, and lived in the metropolitan Vancouver area. / PSG and questionnaire before and after 4 months of treatment. / High Risk
Gagnadoux et al, 2009 [25] / Gender: 46 M/13 F
Age:
50.3±9.1years / AHI between 10 and 60 events per hour
Two or more symptoms of OSAHS, including snoring, witnessed apnoea or complaint of daytime sleepiness. /
  • Previous treatment for OSAHS
  • Body mass index >35 Km.m2
  • Coexisting sleep disorders other than OSAHS
  • Inadequate dental structure or temporomandibular joint disease contraindicating MAD treatment as assessed by a dentist.
  • Unstable medical illness
  • Severe sleepiness which may constitute risk to self or others
/ One-night PSG titration of both effective MAD and CPAP pressure, and then after 8 weeks of treatment. / Unclear risk
Hoekema et al, 2008 [29] / Age > 20 years old / Individuals over age 20 yrs who underwent polysomnography and were diagnosed as having obstructive sleep apnea were eligible.
Participants were selected based on medical, psychological, and dental criteria. / Baseline: physical and neurobehavioral examination.
Second PSG after 8 weeks of CPAP/MAD use; Third PSG at 4 weeks for those whose AHI was still > 5. / Unclear
Risk
Lam et al, 2007 [26] / Gender:
CPAP: 27 M/7 F
MAD: 26M/8F
CM: 26M/7F
Age:
45.7 average years / Apnoea-hypopnea index (AHI) >5-40
Epworth Sleepiness Scale (ESS) >9 for those with AIH 5-20 /
  • Sleepiness which may constitute risk to self or others,
  • unstable medical diseases
  • Coexistence of sleep disorders other than OSA
  • history of previous surgery to upper airway (except those for nasal problems)
  • Pregnant women.
/ Baseline BP during PSG and the next morning. Daytime sleepiness was assessed with ESS. Quality of life assessed with SF-36 and the Sleep Apnoea Quality of Life Index
Same assessments after 10 weeks. / Unclear Risk
Phillips et al, 2013 [27] / Gender:
102M/24 F
Age:
49.5±11.2 years / Patients newly diagnosed OSA (AHI > 10 events per h)
Aged 20 years or older
Greater than or equal to two symptoms of OSA
Willingness to both treatments /
  • Previous OSA treatment
  • need for immediate treatment based on clinical judgment
  • central sleep apnea
  • coexisting sleep disorder
  • regular use of sedatives or narcotics
  • preexisting lung or psychiatric disease
  • contraindication for oral appliance therapy
/ Cardiovascular neurobehavioral, SF-36 were compared between treatments. / High Risk
Schütz et al, 2013 [39] / Gender:
25M/0F
Age:
CPAP: 38.62+8.15
MAD: 42.33+6.20
Exercise Group: 42.28+8.28 / 25 to 55 years of age
Sedentary
Body mass index < 30 kg/m2
AHI > 10 /h
Hemogram, cholesterol, HDL, triglycerides, fasting glucose, creatinine, TSH within the normal range
Lung function test, chest X-rays (For smokers and former smokers), resting and stress electrocardiogram and otorhinolagyngologic examination without significant changes. /
  • Habits or occupations that lead to sleep deprivation or alterations in the sleep-wake cycle
  • History of regular sports activities
  • Inability to perform physical exercise
  • Other sleep disorders
  • Anatomical obstructive upper airway: tonsils grade III and IV and septal deviation grade III (severe) that can affect the outcome of CPAP use
  • Clinical disease decompensation
  • Use of sleeping pills
  • Other treatments for OSA
  • Loss of dental support that subsequently compromises the retention of OA
  • Periodontal disease
  • Dental Crown/tooth root relationship less than or equal to 1
  • Primary dental care (cavities, root canal treatment or retreatment or extensive dental prostheses)
  • Anterior open bite
  • Protrusive displacement less than 5 mm
  • Limited mouth opening
  • Alcoholism
/ Baseline PSG, BP blood samples and daytime sleepiness measurements and after two months of physical exercise or treatment with CPAP or MAD / High
Risk
Tan et al, 2002 [40] / Gender: 20 M/4 F
Age:
50.9 ± 10.1 years / Male or female over the age of 18 years
Adequate dentition and periodontal status
No Temporomandibular joint dysfunction
No medical contraindications /
  • Significant heart disease
  • Myocardial infarction in the last 3 years
  • Angina
  • Uncontrolled hypertension
  • COPD
  • Regular hypnotic use
  • Epilepsy
  • Inadequate dentition
  • Arterial oxygen saturation of less than 60 per cent during the initial sleep study
  • Failure to understand the purpose of the study because of language difficulties.
/ PSG was performed before and after each intervention / Unclear Risk

Abbreviations: EDSI= excessive daytime sleepiness index; PSG= Polysomnography; ESS= Epworth Sleepiness Scale; AHI=Apnea-Hypoapnea Index; OSA= Obstructive Sleep Apnea; SF-36= 36-item Short-Form survey; FOSQ= Functional Outcomes of Sleep Questionnaire; SpO2= Blood oxygen saturation level.