Table 2. Results of available comparisons regarding the primary and secondary outcomes in adult patients with obstructive sleep apnea.

	Outcome	Trials	Patients	Effect (95% CI)	p value	Sign.	Heterogeneity				Largest trial	Egger’s test
							τ2	I2	Comment	Consistent	Effect (95% CI)	Sign.
Intraoral appliance versus placebo appliance
A	AHIcon*1	12	525	MD: −11.7 [−15.38; −8.01]	<0.001	**	20.2	93.6 %	High	Yes	−9.3 [−12.00; –6.60]	NS
B	ESS*2	11	475	MD: −1.18 [−2.38; 0.03]	0.055		2.1	60.6 %	Moderate	No	−2. 01 [−2.70; −1.32]	NS
C	Min satur*3	6	286	MD: 3.33 [1.38; 5. 28]	0.007	*	2.2	96.8 %	High	Yes	1.90 [0.51; 3.29]	–
Intraoral appliance versus no appliance
D	AHIcon	1	24	MD: –14.30 [−21.59; −7.01]	<0.001	**	–	–	–	–	Same	–
E	AHIbin	1	23	RR: 0.37 [0.15; 0.90]	0.029	*	–	–	–	–	Same	–
F	ESS	1	23	MD: –1.00 [–3.77; 1.77]	0.479		–	–	–	–	Same	–
Intraoral appliance1 versus intraoral appliance2
G	AHI	1	23	MD: –2.00 [–6.51; 2.51]	0.385		–	–	–	–	Same	–
Intraoral appliance1 versus intraoral appliance2
H	ESS	1	67	MD: – 6.00 [−8.41; −3.59]	<0.001	**	–	–	–	–	Same	–

AHI. apnea hypopnea index; con. continuous; bin. binary; CI. confidence interval; ESS. Epworth Sleepiness Scale; MD. mean difference; Min Satur. mimimum oxygen saturation;

Sign.. statistically significant at 5%.

intraoral appliance₁ intraoral appliance with 4 mm opening; intraoral appliance₂. intraoral appliance with 14 mm opening

*¹ 95% Predictive Intervals; Estimate: –22.55.–0.85; Consistent: Yes

*² 95% Predictive Intervals; Estimate: –4.76.2.40; Consistent: No

*³ 95% Predictive Intervals; Estimate: –1.62.8.28; Consistent: No