Mouth Puffing Phenomenon and Upper Airway Features May Be Used to Predict the Severity of Obstructive Sleep Apnea

Figures & data

Figure 1 Flowchart summarizing the study procedure.

Abbreviations: PSQI, Pittsburgh Sleep Quality Index; ESS, Epworth Sleepiness Scale; w/o MT, when not mouth-taped; w/ MT, when mouth-taped.

Figure 2 Images to demonstrate how the participants slept with their mouths sealed by the breathable tape throughout the night.

Figure 3 Measurements of the upper airway variables in CBCT images: transverse dimension variables of oral cavity variables in CBCT images.

Abbreviations: (a) MWA, minimum width of the airway; (b) NW, nasal width; (c) U6sW, upper inter-molar width; (d) U3W, the distance between the upper canine tips.

Figure 4 Sagittal and vertical dimension variables of the upper airway, soft tissue, and oral cavity in cephalometric images.

Abbreviations: MTSP, the narrowest dimension between the posterior part of the uvula and the anterior wall of the nasopharynx; MTIP, the narrowest dimension between the posterior part of the tongue and the anterior wall of the oropharynx; UL, length of uvula; MP, the distance between hyoid bone to mandibular plane; SNB, Angle between sella-nasion and nasion-B point; Co-Gn, Mandible length; ANS-Me, Anterior lower facial height; S-Go: Posterior facial height.

Table 1 Compare the ODI Improved Group and the ODI Not-Improved Group After Mouth-Taped

	All (N=58)	ODI Improved Group (n=30)	ODI Not-Improved Group (n=28)	p-value
Gender, male (%)	45 (77.6)	21 (70)	24 (85.7)	0.157
Age (year)	46.02±7.16	44.63±7.84	47.50±6.16	0.129
Body mass index	27.77±4.70	27.17±4.74	28.33±4.68	0.373
Neck circumference	40.41±3.88	39.82±3.78	40.95±3.96	0.292
PSQI	8.06±2.80	8.42±2.80	7.68±2.81	0.349
ESS	10.92±3.58	10.58±3.80	11.28±3.39	0.489
w/o MT_ODI (per hour)	23.79±14.90	24.94±15.72	22.55±14.16	0.546
w/o MT_Mean SpO2 (%)	95.35±1.90	95.60±1.98	95.08±1.82	0.306
w/o MT_Minimum SpO2 (%)	76.47±7.81	75.77±7.46	77.21±8.24	0.485
w/o MT_T 90 (%)	6.18±10.08	6.09±11.36	6.29±8.70	0.939
MT_ODI (per hour)	23.19±17.02	16.37±13.83	30.50±17.30	0.001*
MT_Mean SpO2 (%)	95.26±1.75	95.68±1.64	94.81±1.79	0.058
MT_Minimum SpO2 (%)	75.21±7.84	75.40±7.62	75.00±8.20	0.848
MT_T 90 (%)	6.16±8.86	4.38±8.30	8.06±9.20	0.114
NMP (%)	51.35±25.71	54.47±27.86	48.00±23.21	0.343
IMP (%)	22.64±13.63	19.06±11.88	26.47±14.53	0.037*
CMP (%)	6.97±11.02	8.31±13.28	5.53±7.91	0.341
SMP (%)	19.05±13.66	18.17±14.12	20.00±13.34	0.615

Notes: Data are presented as mean ± SD; * p-value < 0.05.

Abbreviations: w/o MT, when not mouth-taped; MT, when mouth-taped; T90, percentage of SpO₂ under 90; NMP, non-mouth puffing; IMP, intermittent mouth puffing; CMP, complete mouth puffing; SMP, side mouth puffing.

Table 2 Correlation Between the SpO2-Related Variables and MPS Variables of Participants When Not Mouth-Taped

	ODI (Events/Hour)	Mean SpO2 (%)	Minimum SpO2 (%)	T 90 (%)
NMP (%)	−0.45^b	0.50^b	0.27^a	−0.39^b
IMP (%)	0.56^b	−0.55^b	−0.33^a	0.45^b
CMP (%)	0.004	−0.13	−0.08	0.03
SMP (%)	0.29^a	−0.29^a	−0.11	0.25

Note: ^ap < 0.05; ^bp < 0.001.

Abbreviations: ODI, oxygen desaturation index; T90, percentage of SpO₂ under 90; NMP, non- mouth puffing; IMP, Intermittent mouth puffing; CMP, complete mouth puffing; SMP, side mouth puffing.

Table 3 The Data from All the Participants are Categorized into Four MPSs to Assess the Difference in SpO2-Related Variables by Minutes

	All Data (n=19,270)	SMP (n=3526)	CMP (n=1107)	NMP (n=10,357)	IMP (n=4280)	p-value
ODI (events/min)	0.37 ± 0.64	0.41 ± 0.68	0.26 ± 0.56^a	0.27 ± 0.55^a	0.61 ± 0.77^abc	<0.001**
Mean SpO2 (%)	95.29 ± 3.20	95.01 ± 3.20	95.11 ± 2.96	95.91 ± 2.81^ab	94.05 ± 3.71^abc	<0.001**
T90 (%)	3.83 ± 11.55	4.41 ±12.16	3.63 ± 11.74	2.13 ± 8.90^ab	7.51 ± 15.18^abc	<0.001**
SpO2_STD	1.12 ± 1.29	1.19 ± 1.37	0.87 ± 1.07^a	0.90 ± 1.08^a	1.66 ± 1.56^abc	<0.001**

Notes: Data are presented as mean ± SD; n indicates the number of data by minutes; Analysis of variance and Scheffe’s post-hoc tests are used. ^aCompared with side mouth puffing (SMP); ^bCompared with complete mouth breathing (CMP); ^cCompared with complete mouth breathing (NMP); p < 0.001**.

Abbreviations: ODI, oxygen desaturation index; T90, percentage of SpO₂ under 90; SpO₂_STD, standard deviation of SpO₂ in minute; NMP, non-mouth puffing; IMP, Intermittent mouth puffing; CMP, complete mouth puffing; SMP, side mouth puffing.

Table 4 Correlation Between the SpO₂-Related Variables and Basic Information/Upper Airway/Stomatognathic Structure Variables

	w/o MT_ODI	MT ODI	MT T90	NMP	IMP	CMP	SMP
Age	0.022	0.003	−0.091	−0.011	0.158	−0.131	0.130
Gender	0.117	0.234	0.188	0.124	−0.099	−0.163	0.264^a
Body mass index	0.424^b	0.390^b	0.355^b	0.280^a	0.324^a	−0.456^b	0.314^b
Neck circumference	0.306^a	0.310^a	0.300^a	0.333^a	0.130	−0.387^b	0.295^a
MTSP	−0.023	−0.014	−0.042	−0.076	−0.054	−0.028	0.174
MTIP	−0.018	−0.176	−0.118	−0.113	0.171	−0.010	−0.029
MASP	−0.216	−0.365^a	−0.281	−0.200	−0.034	0.252	−0.247
MAIP	−0.082	−0.239	−0.222	−0.044	0.156	0.013	−0.127
MWA	−0.357^a	−0.473^b	−0.474^b	−0.071	−0.087	0.284	−0.376^a
MP	0.248	0.276	0.376^a	0.275	0.014	−0.312^a	0.312
UL	0.230	0.209	0.224	0.333^a	0.301^a	−0.335^a	0.040
Co-Gn	−0.100	−0.117	−0.080	−0.341^a	−0.003	0.202	−0.052
SNB	−0.165	−0.085	−0.181	−0.391^a	0.028	0.262	−0.147
ANS-Me	0.113	0.174	0.170	−0.115	0.024	−0.013	0.113
S-Go	−0.177	−0.185	−0.129	−0.299^a	0.011	0.147	0.001
U6sW	0.055	0.138	0.140	0.040	−0.116	0.052	−0.032
U3W	−0.061	−0.249	−0.112	0.025	−0.068	0.089	−0.130
Nasal width	−0.201	−0.381^b	−0.316^b	−0.045	0.028	0.066	−0.106

Note: ^ap < 0.05; ^bp < 0.001.

Abbreviations: ODI, oxygen desaturation index; T90, percentage of SpO₂ under 90; NMP, non- mouth puffing; IMP, Intermittent mouth puffing; CMP, complete mouth puffing; SMP, side mouth puffing; MTSP, the narrowest dimension between the posterior part of the uvula and the anterior wall of the nasopharynx; MTIP, the narrowest dimension between the posterior part of the tongue and the anterior wall of the oropharynx; MASP, minimum cross-sectional area of post-uvula; MAIP, minimum cross-sectional area of post-tongue; MWA, minimum width of airway; UL, length of uvula; MP, the distance between hyoid bone to mandibular plane; Co-Gn, Mandible length; SNB, Angle between sella-nasion and nasion-B point; ANS-Me, Anterial Lower Face Height; S-Go, Posterior facial height; U6sW, upper inter-molar width; U3W, the distance between the upper canine tips; NW, nasal width.