Table 2.

Descriptive studies.

Author	Sample	Study	PAP mask	Follow up	Evaluation	Results
Li et al. (2000)	One case 15 years	Case report	Nasal mask	10 years	Lateral teleradiography (without mensures)	Hypoplasia of midface and skeletal class III;
						No baseline measures were reported.
Villa et al. (2002)	One case 7 years	Case report	Nasal mask	7 years, 10 h/day (mean)	Lateral teleradiography	Maxillary hypoplasia (ANB = −2.7; SNA = 82.4; SNB = 85.1)
						No baseline measures were reported
						After orthopedic treatment (Delaire mask) associated with PAP there was an improvement in cephalometric measurements
Fauroux et al. (2005)	3 groups:	Cross-sectional	Nasal mask	15 months (mean), at least 6 h/day	Clinical evaluation	68% of the sample had global facial flattening
	OSA group, n = 16 10 years (mean)					43% had flattening of the forehead; 38% had flattening of the malar area and 28% had flattening in the maxilla
	Neuromuscular disturbance group, n = 14 11.8 years (mean)					Concave face was present in 12% of the patients
						Flattening was associated with more than 10 h of use
	Cystic fibrosis group, n = 10 15.8 years (mean)					No baseline measures were reported.
Korayem et al. (2013)	2 groups:	Cross-sectional	Nasal mask	6 months (mean), 5.9 h/day (mean)	Lateral teleradiography by CBCT (SN, BaSN, SNA, PP-SN, CoANS, ANS-PNS, U1-PP, Anperp, OLp-A, SNB, ArFome, FoMe, ANB, Wits)	There were no differences between groups in relation to cephalometric measurements
	OSA CPAP group, n = 12 9 years (mean)					No baseline measures were reported.
	OSA control group, n = 11 10 years (mean)
Roberts et al. (2016)	2 groups:	Retrospective cohort	Nasal mask	2.6 years (mean), more than 20 h/week	Lateral teleradiography (SNA, SN, ANS-PNS, SN-PP, Ba-S-N, A-SN7, A-SN71, U1-SN, U1-PP)	PAP compliant group showed less positive annual cephalometric changes than the PAP non-compliant group (SNA, ANS-PNS, SN-PP, A-SN7, A-SN71, U1-SN, U1-PP), after adjusting for age, gender, and primary craniofacial diagnosis;
	CPAP compliance, n = 50 10 years (mean) CPAP;
	CPAP noncompliant, n = 50 <20 h/week for <6 months 9 years (mean)					The PAP compliant group had more midface retrusion, flaring of the upper incisor and counter-clockwise tipping of the palatal plane than the control.

CBCT, cone beam computer tomography; CPAP, continuous positive airway; OSA, obstructive sleep apnea; PAP, positive airway pressure; ANB (degrees), A-point–nasion–B-point: relative position of mandible to maxilla; A-NPerp (mm), A-point-perpendicular to Frankfort horizontal at N: maxillary projection; ANS-PNS (mm), anterior nasal spine-posterior nasal spine: length of palate; ANS-PNS (mm), length of maxilla; ArGoMe (degrees), articulare–gonion–menton: angle of mandible; A-SN7 (mm), effective maxillary height, vertical distance from anterior maxilla to the SN7 (7° below S-N) line; A-SN7⊥ (mm), effective maxillary length, anteroposterior distance from anterior maxilla to a line perpendicular to the SN7 line; Ba-S-N (degrees), degree of flexure of cranial base; Co-ANS (mm), condylion-ANS: maxillary anteroposterior projection; Go-Me (mm), gonion–menton: length of mandibular body Maxilla-mandible; OLp-A (mm), linear distance between A-point and a line drawn perpendicular to the occlusal plane at sella (OLp); S-N (mm), length of anterior cranial base; SNA (degrees), anteroposterior projection of anterior maxilla relative to anterior cranial base; SNB (degrees), sella–nasion–basion: mandibular anteroposterior projection; SN-PP (degrees), angulation of palatal plane relative to anterior cranial base; U1-SN (degrees), inclination of upper incisor relative to anterior cranial base; U1-PP (degrees), angulation of maxillary incisor to palatal plane; U1-PP (degrees), inclination of upper incisor relative to palatal plane; Wits (mm), distance between perpendiculars to occlusal plane at Points A and B.