Is the growth pattern in mouth breathers comparable with the counterclockwise mandibular rotation of nasal breathers?

Mouth breathing reduces oral function in adolescence

Although humans breathe naturally through the nostrils, mouth breathing in children has recently gathered attention. In this study, we hypothesized that tongue function and its related maxillofacial morphology would affect breathing in adolescence. To verify this hypothesis, we examined the association between breathing patterns, including mouth and nasal breathing; oral functions, including tongue motor function; and craniofacial morphology during adolescence, which has not been investigated till date. C3-H, which indicates the anteroposterior position of the hyoid bone in relation to the third cervical vertebra, was significantly smaller in mouth-breathers than in nasal-breathers. Lip-closing force, tongue pressure, and masticatory efficiency were lower in the order of nasal-breathers, oronasal-breathers, and mouth-breathers, and the values for mouth-breathers were significantly lower than those for nasal-breathers. Tongue pressure alone was identified as a significant independent variable, with an odds ratio of 1.063 (95% confidence interval, 1.006-1.123; p < 0.05). Our results indicate a relationship between mouth breathing and the lip-closing force, tongue pressure, and masticatory efficiency, as well as the significance of tongue pressure on mouth breathing in adolescents. The findings highlight the importance of clarifying the pathophysiology of mouth breathing and its underlying causes.

Analysis of maxillary arch morphology and its relationship with upper airway in mouth breathing subjects with different sagittal growth patterns

OBJECTIVE

This three-dimensional cone beam computed tomography(CBCT) study assessed pharyngeal airway and maxillary arch in mouth breathing subjects with different skeletal classifications and analyzed the factors associated with the upper airway morphological variations in mouth breathing (MB) and nasal breathing (NB) subjects.

METHODS

One hundred and five subjects (52 MB and 53 NB children), divided into three skeletal groups: Class I (1° ≤ ANB° ≤ 5°), Class II (ANB° >5°), and Class III (ANB°<1°). An independent t-test and one-way ANOVA test were utilized in the group analysis of normal distributed data. The linear multiple regression test was applied to create a model for the airway volumes based on the maxillary arch parameters in different skeletal groups.

RESULTS

In three skeletal groups, NB individuals had greater oropharyngeal airway volume (OPV) and total pharyngeal airway volume (TPV) than MB. Maxillary arch parameters of intermolar width (IMW), intercanine width (ICW), and maxillary width of canines (MWC) were larger in NB participants than in MB subjects. In the MB group, we discovered that Class II individuals had lower NPV (nasopharyngeal airway volume) than Class I and Class III. MWC was lower in Class II subjects compared to Class I and Class III in both the NB and MB groups.

CONCLUSION

NB individuals had greater pharyngeal airway and maxillary arch parameters than MB subjects. Our model equation revealed that the inter-molar width (IMW) and palatal area (PA) parameters were the strongest predictors of total pharyngeal airway volume (TPV) in the skeletal Class II and Class I groups.

Three-dimensional evaluation of pharyngeal airway and maxillary arch in mouth and nasal breathing children with skeletal Class I and II

Objective

This study aimed to investigate whether the subjects with mouth breathing (MB) or nasal breathing (NB) with different sagittal skeletal patterns showed different maxillary arch and pharyngeal airway characteristics.

Methods

Cone-beam computed tomography scans from 70 children aged 10 to 12 years with sagittal skeletal Classes I and II were used to measure the pharyngeal airway, maxillary width, palatal area, and height. The independent t-test and the Mann–Whitney U test were used for the intragroup analysis of pharyngeal airway and maxillary arch parameters.

Results

In the Skeletal Class I group, nasopharyngeal airway volume (P < 0.01), oropharyngeal airway volume (OPV), and total pharyngeal airway volume (TPV) (all P < 0.001) were significantly greater in subjects with NB than in those with MB. Furthermore, intermolar width, maxillary width at the molars, intercanine width, maxillary width at the canines, and palatal area were significantly larger in subjects with NB than in those with MB (all P < 0.001). In the Skeletal Class II group, OPV, TPV (both P < 0.05) were significantly greater in subjects with NB than in those with MB. No significant differences in pharyngeal airway parameters in the MB group between subjects with Skeletal Class I and those with Skeletal Class II.

Conclusion

Regardless of sagittal Skeletal Class I or II, the pharyngeal airway and maxillary arch in children with MB differ from those with NB. However, the pharyngeal airway was not significantly different between Skeletal Class I and II in children with MB.

Morphofunctional changes following adenotonsillectomy of obstructive sleep apnea children: a case series analysis

Objective

To perform a case series analysis of the changes in the pulmonary artery systolic pressure (PASP), nasal inspiratory flow (NIF), upper airway volume, obstructive apnea/hypopnea index (OAHI), and the maxillomandibular three-dimensional (3D) morphology after adenotonsillectomy (T&A) of obstructive sleep apnea children (OSA).

Materials and methods

Retrospective assessment of files from 1002 children screened between 2012 and 2020 in a hospital-based mouth-breather referral center. From this universe, 15 obstructive sleep apnea children (7 females; 8 males), ages 4.1 to 8.9 years old (mean age of 5.4 years ± 1.3), who presented indications of tonsillectomy and/or adenoidectomy were selected. The complete baseline examination (T0) was carried out before T&A and a second complete examination (T1) was made 18.7-month follow-up after T&A (ranging from 12 to 30 months). Eleven patients were submitted to T&A, and four patients had indications but did not receive authorization for surgery from the public health system. According to the protocol of the outpatient clinic for OSA patients, Doppler echocardiography, polysomnography, rhinomanometry, and computed tomography imaging was performed at (T0) and (T1).

Results

PASP decreased 16.6% after T&A. NIF increased more in T&A children (40.3%) than in non-T&A children (16.8%). The upper airway volume increased in T&A and non-T&A children, but greater volumetric gain (45.6%) was found in the nasopharynx of T&A patients. OAHI did not change in six T&A children (55%) and three non-T&A children (75%). The maxilla displaced downward and backward relative to the cranial base in six T&A children (55%) and two untreated children (50%). Nine of the T&A children (85%) and three untreated children (75%) presented extensive condylar growth and increased mandibular length. The qualitative 3D assessment showed similar morphological 3D changes in T&A and non-T&A patients.

Conclusion

Pulmonary artery systolic pressure decreased, nasal inspiratory flow increased, and nasopharynx volume increased following adenotonsillectomy, but obstructive apnea/hypopnea index and maxillomandibular morphology were similar in surgical and non-surgical patients.

The role of craniofacial maldevelopment in the modern OSA epidemic: a scoping review

STUDY OBJECTIVES

There is increasing recognition that environmental factors affect human craniofacial development and our risk for disease. A scoping review of the literature was performed looking at environmental influences on craniofacial development to better understand this relationship and investigate what further study is needed to determine how this relationship may impact obstructive sleep apnea.

METHODS

A comprehensive literature search was performed using the Ovid Medline database from inception to May, 2020 with relevance to craniofacial development in 5 clinically-oriented variables: diet, secular change, breastfeeding/non-nutritive sucking habits (NNSH), nasal obstruction/mouth breathing, and masticatory muscle function. The Oxford Centre for Evidence-Based Medicine Levels of Evidence (LoE) was used to assess studies based on study design.

RESULTS

18,196 articles were initially identified, of which 260 studies were fully reviewed and 97 articles excluded. The remaining 163 articles were categorized as follows: Secular change (n = 16), Diet (n = 33), Breastfeeding/NNSH (n = 28), Nasal obstruction/Mouth breathing (n = 57), and Masticatory muscle function (n = 35). 93% of included studies reported a significant association between craniofacial morphology and environmental factors. The majority of studies were characterized as low LoE studies with 90% of studies being LoE 4 or 5.

CONCLUSIONS

The studies in this review suggest that environmental factors are associated with changes in craniofacial development. However, most studies were heterogeneous and low-level studies, making strong conclusions about these relationships difficult. Future rigorous studies are needed to further our understanding of environmental influences on craniofacial development and OSA risk.

Effects of mouth breathing on facial skeletal development in children: a systematic review and meta-analysis

Background

Mouth breathing is closely related to the facial skeletal development and malocclusion. The purpose of this systematic review and meta-analysis was to assess the effect of mouth breathing on facial skeletal development and malocclusion in children.

Methods

An electronic search in PubMed, the Cochrane Library, Medline, Web of Science, EMBASE and Sigle through February 23rd, 2020, was conducted. Inclusion criteria were children under 18 years of age with maxillofacial deformities due to mouth breathing. The risk of bias in nonrandomized studies of interventions (ROBINS-I) tool for controlled clinical trials. The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) approach was used for the quality assessment. The included indicators were SNA, SNB, ANB, SN-OP, SN-PP, PP-MP, SNGoGn, MP-H, 1-NA, 1. NA, 1. NB, 1-NB, Overjet, Overbite, SPAS, PAS, and C3-H. Data concerning the mean difference in mesial molar movement and extent of canine retraction were extracted for statistical analysis. The mean differences and 95% confidence intervals were analyzed for continuous data. Review Manager 5.3, was used to synthesize various parameters associated with the impact of mouth breathing on facial skeletal development and malocclusion.

Results

Following full-text evaluations for eligibility, 10 studies were included in the final quantitative synthesis. In Sagittal direction, SNA (MD: − 1.63, P < 0.0001), SNB (MD: − 1.96, P < 0.0001) in mouth-breathing children was lower than that in nasal-breathing children. ANB (MD: 0.90, P < 0.0001), 1. NA (MD: 1.96, P = 0.009), 1-NA (MD: 0.66, P = 0.004), and 1-NB (MD: 1.03, P < 0.0001) showed higher values in children with mouth breathing. In vertical direction, SN-PP (MD: 0.68, P = 0.0050), SN-OP (MD: 3.05, P < 0.0001), PP-MP (MD: 4.92, P < 0.0001) and SNGoGn (MD: 4.10, P < 0.0001) were higher in mouth-breathing individuals. In airway, SPAS (MD: − 3.48, P = 0.0009), PAS (MD: − 2.11, P < 0.0001), and C3-H (MD: − 1.34, P < 0.0001) were lower in mouth breathing group.

Conclusions

The results showed that the mandible and maxilla rotated backward and downward, and the occlusal plane was steep. In addition, mouth breathing presented a tendency of labial inclination of the upper anterior teeth. Airway stenosis was common in mouth-breathing children.

Trial registration crd-register@york.ac.uk, registration number CRD42019129198.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01458-7.

Facial morphological characteristics of mouth breathers vs. nasal breathers: A systematic review and meta-analysis of lateral cephalometric data

The present systematic review and meta-analysis was performed to assess the association between mouth breathing and facial morphological characteristics in children and adolescents. PubMed, Medline, Scopus and Google Scholar databases were searched for cross-sectional case-control studies published between 1^st January 1980 and 1^st April 2019. Studies comparing cephalometric data of mouth breathers and nasal breathers were included, while studies on adults were excluded. Meta-analysis was performed regarding 11 angular and 4 linear measurements. A total of 19 studies were included in the systematic review and data from 18 studies were extracted for the meta-analysis. The results indicated statistically significant decreases in Sella-Nasion-Point A (SNA) angle [mean difference (MD)=-1.33; 95% CI -2.03 to -0.63; P=0.0002] and Sella-Nasion-Point B (SNB) angle of mouth breathers as compared to nasal breathers (MD=-1.33; 95% CI -2.18 to -0.49; P=0.002). There was no difference in Point A-Nasion-Point B (ANB) angle between the two groups (MD=0.25; 95% CI -0.26 to 0.75; P=0.34). Mouth breathers demonstrated an increased mandibular plane angle, total and lower anterior facial height and decreased posterior facial height. Within the limitations of the study, the results indicated that mouth breathers tended to have a retrognathic maxilla and mandible, vertical growth pattern with high mandibular plane angle, downward and backward rotation of the mandible and an increase in total and lower anterior facial height and decrease in posterior facial height. Further high-quality studies are required to strengthen the evidence on this subject.

[The nose, an orthodontic-surgical marker]

INTRODUCTION

Inthe quest for a universal marker to describe the physiological function of facialmechanics, the author has found nasal ventilation at rest to be a major factor to beborne in mind.

MATERIALS AND METHODS

Factors related to embryology, anatomyand respiratory physiology, along with analysis of the literature in the relevantareas, now enable us to view the nose in a different light.

CONCLUSION

The authorconcludes that nasal ventilation at rest constitutes a mandatory objective in theperformance of all types of therapy.

Breathing mode influence on craniofacial development and head posture

OBJECTIVE

The incidence of abnormal breathing and its consequences on craniofacial development is increasing, and is not limited to children with adenoid faces. The objective of this study was to evaluate the cephalometric differences in craniofacial structures and head posture between nasal breathing and oral breathing children and teenagers with a normal facial growth pattern.

METHOD

Ninety-eight 7-16 year-old patients with a normal facial growth pattern were clinically and radiographically evaluated. They were classified as either nasal breathing or oral breathing patients according to the predominant mode of breathing through clinical and historical evaluation, and breathing respiratory rate predomination as quantified by an airflow sensor. They were divided in two age groups (G1: 7-9) (G2: 10-16) to account for normal age-related facial growth.

RESULTS

Oral breathing children (8.0±0.7 years) showed less nasopharyngeal cross-sectional dimension (MPP) (p=0.030), whereas other structures were similar to their nasal breathing counterparts (7.6±0.9 years). However, oral breathing teenagers (12.3±2.0 years) exhibited a greater palate length (ANS-PNS) (p=0.049), a higher vertical dimension in the lower anterior face (Xi-ANS-Pm) (p=0.015), and a lower position of the hyoid bone with respect to the mandibular plane (H-MP) (p=0.017) than their nasal breathing counterparts (12.5±1.9 years). No statistically significant differences were found in head posture.

CONCLUSION

Even in individuals with a normal facial growth pattern, when compared with nasal breathing individuals, oral breathing children present differences in airway dimensions. Among adolescents, these dissimilarities include structures in the facial development and hyoid bone position.

Maxillary dentoskeletal changes 1-year after adenotonsillectomy

OBJECTIVE

To measure the maxillary dentoskeletal and soft tissue changes of severely obstructed mouth breathing (MB) young children who had their mode of breathing normalized after adenotonsillectomy (T&A), in comparison with a matched group of severely obstructed untreated MB children (CG).

METHODS

Seventy patients who had an Ear, Nose, and Throat examination (ENT), including flexible nasal endoscopy, to confirm the severe obstruction of the upper airways and the indication of T&A composed the sample. Cephalograms and dental casts were available from the patient's orthodontic records. Treatment group (TG) and CG included 35 children each. Groups were matched by gender (24 males and 11 females in each group), age (TG, 6.7 ± 1.8 years; CG, 6.9 ± 2.3 years), tooth development (TG, 13 primary dentition, 22 mixed dentition; CG, 14 primary dentition, 21 mixed dentition), and skeletal maturation status. Records were taken at baseline (T0) and 1-year after T&A (T1) for TG; while CG records were taken with a 1-year interval. Dentoskeletal measurements were performed in the lateral cephalograms, and dental casts were used to assess the palatal volume and occlusal changes.

RESULTS

TG showed a significant increase (503.3 mm(3), P < 0.001) in the palatal volume (10% of change), while CG palatal volume was stable. No dimensional occlusal changes were detected between T0 and T1 in both groups. Significant downward (point A, 2.1 mm; ANS, 2.1 mm) and forward displacements (point A, 0.7 mm; ANS, 1 mm) of the anterior region of the maxilla were observed in the TG, but CG presented only significant downward displacement (point A, 1.8 mm; ANS, 1.4 mm). The maxillary posterior region (PNS, PTM, and Molar) displaced downward in both groups (P < 0.05), however no sagittal change was found. The palatal plane inclination was stable in both groups.

CONCLUSIONS

TG presented significant increase in the palatal volume and in the forward displacement of the maxilla. No other significant maxillary dentoskeletal changes were found.

Cephalometric pattern and nasal patency in children with primary snoring: the evidence of a direct correlation

Introduction

Sleep disordered breathing (SDB) might affect craniofacial growth and children with obstructive sleep apnea syndrome present an increase in total and lower anterior heights of the face and a more anterior and inferior position of the hyoid bone when compared to nasal breathers.

Objective

To investigate the correlation between rhinomanometric and cephalometric parameters in children with primary snoring (PS), without apnea or gas exchange abnormalities.

Materials and Methods

Thirty children with habitual snoring (16 females and 14 males) aged 4–8 years (mean age 6.85±1.51 years) were selected by a SDB validate questionnaire. All subjects underwent lateral cephalometric, panoramic radiographies.

Results

In our sample 10 children (33%) had snoring 3 nights/week, 11 (37%) 4–6 nights/week and 9 (30%) every night/week. Overall 7 patients (23.3%) were affected by adenoid hypertrophy (AH), 4 (13.3%) by tonsillar hypertrophy (TH) and 13 (43.3%) by AH and TH. We found a more vertical position of the hyoid bone to the mandibular plane (H⊥VT) in patients with a higher frequency (7.3±2.7 vs 7.6±3.7 vs 10.9±2.5 in children snoring 3 nights/week, 4–6 nights/week and every night/week respectively; p = 0.032). Concerning nasal patency significant correlations were found with ANB (maxillary and jaw position with respect to the cranial base), NS∧Ar (growth predictor), sumangle, FMA (total divergence), SnaSnp∧GoMe (inferior divergence), BaN∧PtGn (facial growth pattern), Phw1_PsP (posterosuperior airway space), AHC3H (the horizontal distance between the most anterosuperior point of the hyoid bone and the third cervical vertebra).

Conclusion

The present study supports the relationship between nasal obstruction and specific craniofacial characteristics in children with primary snoring and lead us to hypothesize that nasal obstruction might explain the indirect link between snoring and cephalometric alterations.

Comparison of cephalometric patterns in mouth breathing and nose breathing children

OBJECTIVE

The aim of this study was to compare cephalometric values between nasal and oral breathing children and to measure the upper and lower airway space in both groups.

METHODS

The study was conducted on 118 pediatric patients, 51 girls and 67 boys, from the Dental Clinic of the Universidad Europea de Madrid. The age ranges of the sample were 6-12 years old. 53 of them were mouth breathers and 65 nose breathers. Lateral cephalometric radiographs were obtained for all of the subjects. The radiographs were analyzed and a cephalometric tracing was performed on each one.

RESULTS

The mouth breathing children showed a more retruded mandible (SNB), and a greater inclination of the mandibular plane (NS-Go Gn) and occlusal plane (NS-O Pl.), than the nose breathing children (P<0.05). The mouth breathing group also had a higher frequency of having the hyoid bone in a more elevated position and the nasopharyngeal air space significantly smaller than the nasal breathing group (P<0.001).

CONCLUSION

Mouth breathing children seem to have an increase in anterior lower facial height, the hyoid bone in a more elevated position and higher tendency towards having a class II malocclusion compared to nose breathing children.

Facial soft tissues of mouth-breathing children: do expectations meet reality?

OBJECTIVE

To quantify the differences between the facial soft tissue morphology of severely obstructed mouth breathing (MB) and that of predominantly nasal breathing (NB) children.

METHODS

Soft tissue measurements were performed in the lateral cephalograms of 64 severely obstructed MB children (mean age 6.7 ± 1.6) compared with 64 NB children (mean age 6.5 ± 1.3). Groups were paired by age, gender, skeletal maturation status and sagittal skeletal pattern. Based on the assumption of normality and homoscedasticity, comparison of the means and medians of soft tissue measurements between the two groups was performed.

RESULTS

The facial convexity and anterior facial height ratio of MB were similar to NB children. The upper lip of MB children was protruded, and its base was thinner compared with NB; however, the length was not affected. The lower lip was shorter and more protruded in MB children. The nasolabial angle, nasal prominence, and chin thickness were smaller in MB children.

CONCLUSIONS

The facial soft tissue of severely obstructed MB children is different than in NB children. Changes in lips, nasolabial angle, nasal prominence, and chin thickness are associated with severe airway obstruction in children.