Table 2.

Summary of the studies included in the systematic review (n = 10).

Studies	Sample and type of diagnosis	Instrument	Postural variables measured	Results	Conclusions
Okuro et al.,12 Cross-sectional	8–11 years 45 Mouth breathing 16 F–29 M 62 Nose breathing 23 M–39 F Clinical diagnosis	New York Postural Rating (NYPR)	Neck posture: anterior head position with flexion of the lower portion and extension of the upper portion of the spine Alignment of the head: anterior tilting of the head	Mouth breathing: 36 (80%) and nose breathing: 30 (48.4%) OR = 4.27 [95% CI: 1.63–11.42], p < 0.001 of having altered head posture. Mouth breathing: 18 (40%) and nose breathing: 33 (53.2%) OR = 0.59 [95% CI: 0.25–1.37], p = 0.176 of having altered body posture	Mouth breathing children presented cervical postural changes compared to nose breathing children
Conti et al.,11 Cross-sectional	5–14 years 323 Mouth breathing 124 Nose breathing Clinical diagnosis	New York Postural Rating (NYPR) assessed observationally of 13 body segments and scored as severe, moderate and normal	Full body alignment: posterior and lateral view neck, shoulders, spine, abdomen, hips, feet and arches Detailed description of the measurements were not provided	Mouth breathing: 60.74% normal posture, 29.63% moderate, 9.63% severe postural abnormalities Nose breathing: 56.20% normal posture, 42.98% moderate posture, 0.83% severe postural abnormalities Posterior view: head, shoulder, feet and arches significantly different between groups (p ≤ 0.0002) Lateral view: thorax, shoulder, spine, trunk and abdomen significantly different between groups (p ≤ 0.0003). Neck posture did not differ between groups in the lateral view (p = 0.260) Odds ratio (95% CI) of the mouth breathing group for the score of full body alignment: Severe × Normal: odds ratio of 24.99 (95% CI: 3.127–194.127) Moderate × Normal: odds ratio of 2.911 (95% CI: 1.775–4.774)	The study showed an association between mouth breathing and body posture in children and adolescents
Bolzan et al.,4 Cross-sectional	8–11 years 22 Obstructive mouth breathing 10 F–10 M 15 Habitual mouth breathing 9 F–13 M 15 Nose breathing 13 F–2 M Diagnosis by video nasofibroscopy	Photography Postural Software Analysis (SAPo v0.68®)	Lateral view: Head posture measured through the angle formed by the tragus, seventh cervical vertebra and the horizontal line	Head posture: Nose breathing: 46.15° ± 4.27° Obstructive mouth breathing: 45.71° ± 4.34° Habitual mouth breathing: 45.09° ± 5.42° No difference among groups (p = 0.45)	The study showed that head posture seems to be not influenced by breathing pattern
Silveira et al.,3 Cross-sectional	8–12 years 17 Mouth breathing 7 F–10 M 17 Nose breathing 9 F–11 M Clinical diagnosis	Photography Postural Software Fisiometer®	Sagittal view: Head projection: distance from a straight line drawn perpendicular to the ground and passing behind and near to the body to markers placed at temporomandibular joint Shoulder projection: distance from a straight line drawn perpendicular to the ground and passing behind and near to the body to markers placed at the acromioclavicular joint Neck lordosis: distance from a straight line drawn perpendicular to the ground and passing behind and near to the body to markers placed, not clearly specified, on the neck region. Lumbar lordosis: distance from a straight line perpendicular to the ground and passing behind and near to the body to markers placed, not clearly specified, on the lumbar region.	Head projection: Greater distance between the posterior line and the marker at the temporomandibular joint in the mouth breathing group (14.3 cm) × nose breathing (11.7 cm) group, p = 0.005 Neck lordosis: Greater distance between the posterior line and the neck in the mouth breathing (7.3 cm) × nose breathing (5.4 cm) group, p = 0.016 No differences were found for the shoulder projection distance 13.5 cm × nose breathing 11.1 cm, p = 0.2 and for the lumbar lordosis distance (mouth breathing 6.3 cm × nose breathing 5.9 cm, p = 0.49	Mouth breathing children have head projection and neck hyperlordosis
Roggia et al.,14 Cross-sectional	8–12 years 51 Mouth breathing 20 F–31 M 58 Nose breathing 34 F–24 M Clinical diagnosis	Photography Postural Software Analysis (SAPo v0.68®)	Full body alignment comparing the right and left sides of the head, pelvis, line of gravity, knee and ankle segments of boys and girls. Horizontal alignment of the head: angle between the tragus, C7 spinous process and the horizontal. The smaller the angle, the greater the forward head posture. Vertical alignment of the body: the angle between acromion, vertical and lateral malleolus. Positive angular measure: body leaning forward, and negative, backward. Horizontal alignment of the pelvis: the angle between the anterior superior iliac spine, posterior–superior and horizontal. Negative angular measurement: concavity close to zero: rectification, less negative closer to normal. Knee angle: angle between the greater trochanter, the knee joint line and lateral malleolus Ankle angle: angle between the knee joint line, lateral malleolus and horizontal. Measure angle >90°: tibia tilted back, if <90°: tibia bending forward	Full Body alignment left × right views: knee angle statistically different between right and left side views of mouth breathing boys (R side: 3.70 ± 6.28 and L side: −0.41 ± 6.03, p = 0.0143); no difference found in the group of nose breathing boys and mouth breathing and nose breathing girls Comparisons between groups: Females: significantly difference in the horizontal head alignment angle, with greater forward head posture of the female mouth breathing group (46.95° ± 5.65°) × Nose breathing group (49.49° ± 6.01°), p = 0.0486; but no difference in the other measurements Males: significantly difference in ankle angle between males of the Mouth breathing × nose breathing (mouth breathing: 84.74° ± 3.12° and nose breathing: 83.1° ± 2.74°, p = 0.0034); but no difference in the other measurements	Mouth breathing school boys presented hyperextended knee and decreased ankle angle compared to mouth breathing boys, suggesting an adaptation due to the excess of knee extension Mouth breathing school girls presented forward head posture compared to nose breathing girls
Neiva et al.,10 Cross-sectional	8–12 years 21 Mouth breathing 21 Nose breathing Diagnosis by Video nasofibroscopy	Qualisys ProReflex system MATLAB for data analysis	Scapular elevation: obtained from vertical distance in millimeters from the marker positioned over C7 to the centroid point of the scapula. Greater scapular elevation indicated a lesser distance between markers Protrusion of the shoulders: angle obtained from the intersection of a straight line passing through the posterior angle of the acromion and C7 with a straight horizontal line intercepting the posterior acromion on the sagittal plane. An increased angle indicates that the shoulder is projected forward in relation to C7 Anterior tilt of the scapula: angle obtained from the intersection of a straight line passing through C7 and T7 markers and a straight line passing through markers on the posterior angle of the acromion and centroid of the scapula Scapular abduction: corresponds to the horizontal distance in millimeters from the centroid point of the scapula to the spinal column Forward head position: obtained from the angle formed by the intersection of a straight line passing through the marker on the tragus of the ear and C7 and a straight horizontal line intercepting C7 on the sagittal plane. This angle described the position of the head in relation to C7 Thoracic kyphosis: measured as the sum of the angles formed by the intersection of a straight line passing through T2 and the marker positioned 4.5 cm below T2 with a vertical axis and the angle formed by the intersection of a straight line passing through T12 and a marker positioned 4.5 cm above T12 with the same vertical axis Upward rotation of the scapula: angle obtained from the intersection of a straight line passing through the C7 and T7 markers and a line passing through the markers over the medial edge of the root of the scapular spine and the inferior angle of the scapula Internal rotation of the scapula: obtained from the intersection of a horizontal rod positioned in the abdominal region (frontal plane) with a straight line passing through markers located on the root of the scapula spine and the posterior angle of the acromion.	MB children presented significantly increased superior scapular position of the right (72.39 ± 10.71 mm) and left scapula (75.24 ± 10.45 mm) compared to the right (81.0 ± 9.85 mm) and left scapular position (82.64 ± 8.40 mm) of the nose breathing group (p < 0.05) Shoulder protrusion: no difference in the right (141.54° ± 11.2°) and left (138.31° ± 13.74°) of the mouth breathing group compared to the right (139.02° ± 11.2°) and left (132.63° ± 9.87°) of the nose breathing group (p > 0.05) Anterior tilt of the scapula: no difference in the right (49.56° ± 6.42°) and left (49.27° ± 7.34°) of the mouth breathing group compared to the right (50.8° ± 7.39°) and left (48.46° ± 9.95°) of the nose breathing group (p > 0.05) Scapular abduction: no difference in the right (95.11 ± 7.46 mm) and left (96.13 ± 6.03 mm) of the mouth breathing group compared to the right (96.3 ± 6.3 mm) and left (101.09 ± 10.96 mm) of the nose breathing group (p > 0.05) Forward head position: no difference in the right (48.9° ± 4.4°) and left (48.10° ± 6.8°) of the \mouth breathing group compared to the right (47.59° ± 4.6°) and left (48.50° ± 6.30°) of the nose breathing group (p > 0.05) Thoracic kyphosis: no difference in the mouth breathing group (31.96° ± 10.97) compared to the nose breathing groups (30.82° ± 16.93°) (p > 0.05) Upward rotation of the scapula: no difference in the right (1.01° ± 6.84°) and left (−3.42° ± 6.15°) of the mouth breathing group compared to the right (2.98° ± 3.91°) and left (−2.61° ± 5.86°) of the nose breathing group (p > 0.05) Internal rotation of the scapula: no difference in the right (35.24° ± 4.2°) and left (33.81° ± 5.69°) of the mouth breathing group compared to the right (38.43° ± 6.01°) and left (35.55° ± 6.72°) of the nose breathing group (p > 0.05)	Increased superior scapular position may be due to the forward head, clinically observed in mouth breathing children, that leads to altered position of the mandible
Yi et al.,13 Cross-sectional	5–12 years 30 Mouth breathing 22 Nose breathing Diagnosis by video nasofibroscopy	Photography Postural Software Analysis (SAPO) v0.68®)	Cervical lordosis: angle formed by the tragus of the ear, the acromion and C7. The larger the angle, the further forward the position of the head and the lower the degree of cervical lordosis. Thoracic kyphosis: angle formed by the acromion to L1 and from L1 to T7, where L1 was the apex of the angle. The larger the angle, the greater the degree of thoracic kyphosis. Lumbar lordosis: angle drawn between three anatomic points: L1, ASIS and the greater trochanters, where ASIS was the apex of the angle. The smaller the angle, the greater the degree of lumbar lordosis. Pelvic position: angle drawn between the ASIS, the midpoint of the knee joint on the lateral face and the greater trochanters where the midpoint of the joint line was the apex of the angle. The greater the angle, the greater the pelvic tilt.	Cervical lordosis: significantly difference between mouth breathing (60.36° ± 9.54°) × nose breathing (52.27° ± 8.58°), p = 0.003, with reduced cervical lordosis found on the mouth breathing group. Lumbar lordosis: significantly difference between mouth breathing (102.52° ± 9.67°) × nose breathing (119.84° ± 5.35°), p = 0.001, with increased lumbar lordosis found on the mouth breathing group. Thoracic kyphosis: significantly difference between mouth breathing (45.89° ± 5.26°) × nose breathing (41.33° ± 4.64°), p = 0.002, with increased thoracic kyphosis found on the mouth breathing group. Pelvic position: significantly difference between mouth breathing (9.98° ± 1.49°) × nose breathing (6.93° ± 1.00°), p = 0.001, with increased anterior tilt of the pelvis found on the mouth breathing group.	Mouth breathing children project their heads forward to facilitate airflow. In addition, the children presented decreased cervical lordosis due to the forward projection of the head, increased lumbar lordosis, thoracic kyphosis and anterior pelvic till
Corrêa & Bezin7 Non-randomized clinical trial	9–11 years 19 Mouth breathing 8 F–11 M Diagnosed by video nasofibroscopy	Photography Postural Software ALCimagem	Lateral view: Forward head: angle formed between the plumb line and a line passing the ear lobe Forward shoulder: angle formed between a plumb line a line passing over the acromion Flexion/extension head: angle formed between the plumb line and a line passing over the mentum Scapula abduction or winged scapula: angle formed between the plumb line and a line passing over the scapular prominence Frontal view: Head Tilt right/left: angle formed between a vertical line drawn through the manubrium and a line passing through the left/right ear lobe Shoulder elevation right/left: angle formed between a vertical line drawn through the manubrium and a line passing through the left/right coracoid process Posterior view: Scapular abduction left/right: angle formed between a line passing the superior scapular angle, C7 and superior scapular angle	Baseline × Post treatment Forward head: 9.21° ± 4.51° × 5.99° ± 1.49°, p = 0.003 Forward shoulder: 4.18° ± 2.53° × 2.9° ± 3.13°, p = 0.121 Flexion/extension head: 17.68° ± 4.1° × 15.83° ± 3.04°, p = 0.1027 Abducted/winged scapula: 9.74° ± 2.25° × 8.82° ± 2.49°, p = 0.0458 Head tilt right: 30.19° ± 2.6° × 29.66° ± 3.5°, p = 0.379 Head tilt left: 30.96° ± 3.2° × 31.33° ± 2.6°, p = 0.454 Shoulder elevation right: 84.73° ± 3.22° × 86.37° ± 3.53°, p = 0.236 Shoulder elevation left: 85.56° ± 3.14° × 87.07° ± 4.29°, p = 0.113 Scapular abduction right: 47.09° ± 6.61° × 44.14° ± 5.98°, p = 0.0158 Scapular abduction left: 103.89° ± 12.92° × 103.42° ± 10.12°, p = 0.873	The exercise program was effective in reducing the forward head posture, scapular abduction, shoulder elevation and internal rotation of the scapula on the right side of mouth breathing children
Lima et al.20 Cross-sectional	8–10 years 17 Obstructive mouth breathing 26 Functional mouth breathing 19 Nose breathing Clinical Diagnosis	Photography Postural Software ALCimagem	Lateral view: Chin retraction: angle formed between the glabella, external acoustic meatus and mentum Head forward projection: angle formed between the glabella, external acoustic meatus and manubrium sterni Lateral deviation of the cervical, thoracic and lumbar spine: markers located at greatest cervical, thoracic and lumbar curvatures Pelvis and knee alignment: markers at ASIS, gluteal line, and lateral condyles of the femur Frontal View: Horizontalization of the collarbones: coracoid process, condylar angle and a horizontal line Posterior view: Scapular position: angle between the superior and inferior angle of the scapular and T12	Chin retraction (p = 0.014) and head forward projection (p = 0.0036) were significantly different between the obstructive mouth breathing × nose breathing group. The obstructive mouth breathing group showed more chin and head deviations. Cervical deviations were significantly different between obstructive mouth breathing × nose breathing (p = 0.0004) and obstructive mouth breathing × functional mouth breathing (p = 0.0148) Thoracic deviations were significantly different between obstructive mouth breathing × nose breathing (p = 0.0009) and obstructive mouth breathing × functional mouth breathing (p = 0.0073). The authors classified it at altered thoracic convexity. All the other measurements were not significantly different between the three groups. The values of the angles were not reported.	Obstructive mouth breathing and Functional mouth breathing children presented different spine postural alterations; therefore should be treated differently
Krakauer & Guilherme21 Cross-sectional	5–10 years 30 Nose breathing Clinical diagnosis	Polaroid Camera Observational analysis of the photos	Frontal view: symmetry/asymmetry of the shoulder in relation to the ground. Lateral view: head position (anterior, posterior, or normal) in relation to the neck Dorsal view: symmetry/asymmetry of the scapulae in relation to a perpendicular axis passing through the body.	Frontal view: asymmetry observed in 60% mouth breathing children and 44.4% nose breathing children between 5 and 8 years; and 95% and 33.3% of mouth breathing and nose breathing children, respectively, between the ages of 8.1 and 10 years Lateral view: alteration observed in 80% mouth breathing children and 33.3% nose breathing children between 5 and 8 years; and 100% and 25% of mouth breathing and nose breathing children, respectively, between the ages of 8.1 and 10 years Dorsal view: asymmetry observed in 83.3% mouth breathing children and 44.4% nose breathing children between 5 and 8 years; and 70% and 41.7% of mouth breathing and nose breathing children, respectively, between the ages of 8.1 and 10 years	Children with nose breathing, age 8 and above present better posture than those who continue mouth breathing beyond age 8

M, male; F, female; ASIS, anterior superior iliac spine; T12, twelve thoracic vertebrae; C7, seventh cervical vertebrae.