Mouth Breathing in Children and Adults: Why It Is Harmful and How to Manage It

Mouth breathing is a chronic dysfunctional breathing pattern linked to anatomical obstruction, habits, and sleep-related disorders.

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Its long-term consequences affect craniofacial development, oral health, systemic physiology, and quality of life. Early diagnosis and intervention are essential to prevent irreversible changes, particularly in children.

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✅ Introduction
Mouth breathing refers to the predominant use of the oral cavity instead of the nose for airflow at rest. While occasional mouth breathing during a cold or intense exercise is normal, persistent oral respiration is clinically significant. Research shows that chronic mouth breathing disrupts nasal filtration, alters muscle activity, modifies dental arch development, and contributes to both malocclusions and sleep-disordered breathing (Zaghi et al., 2022). Early identification is crucial because craniofacial structures in children are still developing and more susceptible to functional changes.

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✅ Causes of Mouth Breathing

➤ Anatomical Causes
▪️ Adenoid or tonsillar hypertrophy
▪️ Deviated nasal septum
▪️ Chronic allergic rhinitis
▪️ Nasal polyps
▪️ Inferior turbinate hypertrophy

➤ Functional and Behavioral Causes
▪️ Habitual open-mouth posture
▪️ Thumb sucking or prolonged pacifier use
▪️ Incorrect resting tongue position
▪️ Orofacial muscle hypotonia

➤ Sleep-Related Causes
▪️ Obstructive Sleep Apnea (OSA)
▪️ Primary snoring
▪️ Sleep-disordered breathing secondary to obesity

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✅ Clinical Consequences in Children

➤ Craniofacial Growth Alterations
Chronic mouth breathing can redirect mandibular and maxillary growth patterns, producing the classic long-face syndrome (adenoid facies). Associated findings include:
▪️ Narrow maxilla
▪️ High palatal vault
▪️ Increased lower facial height
▪️ Posterior crossbite
▪️ Class II malocclusion tendencies

➤ Oral Health Impacts
▪️ Increased risk of dental caries due to reduced salivary flow
▪️ Gingival inflammation
▪️ Halitosis
▪️ Lip incompetence and dry mucosa

➤ Systemic and Behavioral Consequences
▪️ Daytime fatigue
▪️ Learning difficulties
▪️ Reduced concentration
▪️ Behavioral issues resembling ADHD
▪️ Poor sleep quality

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✅ Clinical Consequences in Adults

➤ Oral and Periodontal Effects
Persistent oral breathing in adults often leads to:
▪️ Chronic xerostomia
▪️ Gingivitis and periodontitis progression
▪️ Higher susceptibility to root caries

➤ Respiratory and Sleep Effects
▪️ Snoring
▪️ Sleep-disordered breathing
▪️ Reduced oxygen saturation during sleep
▪️ Morning headaches

➤ Musculoskeletal and Postural Changes
▪️ Forward head posture
▪️ Neck and shoulder tension
▪️ Temporomandibular joint (TMJ) discomfort

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✅ Diagnosis

➤ Clinical Evaluation
A comprehensive assessment includes:
▪️ Nasal patency examination
▪️ Lip competence observation
▪️ Tongue posture evaluation
▪️ Adenoid/tonsillar inspection
▪️ Cervicofacial posture assessment

➤ Complementary Exams
▪️ Lateral cephalometric radiograph
▪️ Nasal endoscopy (ENT evaluation)
▪️ Sleep study if OSA is suspected

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✅ Evidence-Based Treatment

➤ Treatment in Children
Management depends on etiology and severity:
▪️ Adenotonsillectomy for obstructive hypertrophy
▪️ Allergy control (intranasal corticosteroids or antihistamines under medical guidance)
▪️ Maxillary expansion (RPE, SME) to widen nasal cavity and improve airflow
▪️ Myofunctional therapy to correct oral posture
▪️ Discontinuation of harmful habits

➤ Treatment in Adults
▪️ Nasal obstruction management (surgical or medical depending on case)
▪️ CPAP if associated with OSA
▪️ Orthodontic or orthognathic treatment when skeletal discrepancies persist
▪️ Orofacial myofunctional training

📊 Comparative Table: Nasal Breathing vs. Mouth Breathing

Aspect	Advantages	Limitations
Nasal Breathing	Filters, warms and humidifies air; supports optimal craniofacial growth	Limited during obstruction or anatomical deviations
Mouth Breathing	Allows airflow when nasal passages are blocked	Leads to malocclusions, dry mouth, poor sleep and systemic effects

💬 Discussion
Chronic mouth breathing is not a simple habit; it is a multifactorial condition with structural, functional, and behavioral consequences. Evidence shows that early intervention produces better outcomes, especially in the pediatric population where craniofacial growth can still be redirected. Adults, on the other hand, often require combined therapies rather than single-modality treatment. A multidisciplinary approach—pediatric dentistry, ENT, orthodontics, speech therapy, sleep medicine—is essential for long-term success.

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✍️ Conclusion
Mouth breathing substantially affects oral health, craniofacial development, systemic physiology, and sleep quality. Early diagnosis and targeted intervention are essential to prevent irreversible complications. Both adults and children benefit from an individualized management plan addressing nasal obstruction, soft-tissue dysfunction, and skeletal discrepancies.

🔎 Recommendations
▪️ Evaluate nasal patency and adenoid/tonsil size in all mouth-breathing children.
▪️ Implement orthodontic expansion when indicated.
▪️ Consider ENT referral early when obstruction is suspected.
▪️ Educate parents about the impact of oral habits on breathing.
▪️ Incorporate myofunctional therapy as part of long-term rehabilitation.
▪️ For adults, screen for sleep-disordered breathing before starting treatment.

📚 References

✔ Villa, M. P., Evangelisti, M., Barreto, M., Cecili, M., & Kaditis, A. G. (2017). Nasal obstruction in children: A clinical review. International Journal of Pediatric Otorhinolaryngology, 99, 81–88. https://doi.org/10.1016/j.ijporl.2017.05.029
✔ Zaghi, S., Patel, P., Barber, R., & Guilleminault, C. (2022). Sleep disordered breathing, mouth breathing, and craniofacial development: The role of myofunctional therapy. Sleep Medicine Reviews, 61, 101572. https://doi.org/10.1016/j.smrv.2021.101572
✔ Camacho, M., Certal, V., Abdullatif, J., et al. (2015). Myofunctional therapy to treat obstructive sleep apnea: A systematic review and meta-analysis. Sleep, 38(5), 669–675. https://doi.org/10.5665/sleep.4652

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Clinical recognition of mouth breathing children

Mouth breathing can be caused by an obstruction or an inappropriate habit. In both situations they generate an imbalance between the bone and muscular structures of the skull.

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Early evaluation and treatment are important to avoid the serious consequences of mouth breathing, and dentists are the first professionals to be able to recognize a patient with mouth breathing.

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We share an interesting guide to recognize the clinical manifestations of a child who breathes through the mouth.

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👉 Read and download the full article"Clinical recognition of mouth breathing children" in PDF👈

Pacheco MCT, Casagrande CF, Teixeira LP, Finck NS, Araújo MTM. Guidelines proposal for clinical recognition of mouth breathing children. Dental Press J Orthod. 2015 July-Aug;20(4):39-44. DOI: http://dx.doi.org/10.1590/2176-9451.20.4.039-044.oar

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Oral breathing: new early treatment protocol

Mouth breathing is multifactorial, and its consequences are short and long term, and it is evident in the oral cavity and in general health. Early evaluation and treatment by the pediatric dentistry and pediatrician is necessary.

We invite you to our English-only dental publishing groups

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The mouth breather is affected cognitively, psychologically and physically. A characteristic sign of the oral respirator is the "adenoid face", which is why most parents attend specialists.

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We share an excellent article that tells us about oral respirators, and the importance of early multidisciplinary treatment (pediatrics - dentistry).

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👉DOWNLOAD AND READ THE FULL ARTICLE IN PDF👈

Denotti, G., Ventura, S., Arena, O., & Fortini, A. (2014). Oral breathing: new early treatment protocol. Journal of Pediatric and Neonatal Individualized Medicine (JPNIM), 3(1), e030108. https://doi.org/10.7363/030108

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► Is Your Child A Mouth Breather?

Is Your Child A Mouth Breather?

Mouth breathing, defined as habitual or chronic inhalation through the mouth rather than the nose, predominantly arises from nasal obstruction but may also become a learned habit.

📌 Recommended Article :

PDF 🔽 Oral breathing: new early treatment protocol ... The mouth breather is affected cognitively, psychologically and physically. A characteristic sign of the oral respirator is the "adenoid face", which is why most parents attend specialists.

In children, persistent mouth breathing is associated with facial morphological alterations, dental malocclusion, sleep disturbances, and behavioral challenges.

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✅ What Causes Mouth Breathing?
Key causes include:

° Nasal obstruction due to enlarged adenoids or tonsils, deviated nasal septum, sinus congestion, or allergic rhinitis.
° Structural anatomical issues, such as a deviated septum or narrow nasal passages.
° Habitual or developmental factors—mouth breathing persisting even without obstruction, sometimes linked to poor orofacial muscle function.
° Inflammatory processes that lead to tissue hypertrophy and chronic obstruction; adenoid hypertrophy forms a cycle of obstruction and atypical facial development.

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✅ What Should Parents Look Out For?
Parents should be alert to:

° Sleep disturbances: snoring, drooling, restless nights, daytime sleepiness or behavioral issues.
° Facial changes: elongated, narrow face, retruded chin, “adenoid facies,” dental crowding, open bite, or malocclusion (often Class II).
° Oral symptoms: dry mouth, hoarseness, bad breath, frequent throat or ear infections.
° Functional issues: difficulty concentrating, poor school performance, speech or swallowing problems.

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✅ What Can Be Done to Treat Mouth Breathing?

1. Address Underlying Causes
° Medical management of allergies or sinusitis with antihistamines, nasal corticosteroids, or decongestants.
° Surgical interventions such as adenoidectomy, tonsillectomy, or septoplasty when structural obstruction is significant; these can boost growth, improve sleep, and correct behavior.

2. Breathing Retraining and Myofunctional Therapy
° Exercises to strengthen orofacial muscles, improve tongue posture, and promote nasal breathing.
° Habit reversal techniques with visual cues and structured practice.

3. Orthodontic and Dental Approaches
° Palatal expanders to widen the upper airway; braces or other appliances to correct malocclusion.

4. Supportive Measures
° Nasal dilators or strips for temporary relief.
° Maintaining a clean, low-allergen environment; using saline sprays, proper sleep posture.
° For sleep apnea cases, CPAP therapy may be used in older children.

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PDF🔽 Clinical recognition of mouth breathing children ... Early evaluation and treatment are important to avoid the serious consequences of mouth breathing, and dentists are the first professionals to be able to recognize a patient with mouth breathing.

💬 Discussion
Persistent mouth breathing in children is more than an innocuous habit—it is a potential contributor to altered facial structure, dental misalignment, poor sleep, and developmental delays. Early recognition by parents and clinicians is essential. Multidisciplinary management—encompassing pediatricians, ENT specialists, orthodontists, speech therapists, and myofunctional therapists—can significantly reverse or mitigate consequences.

✍️ Conclusion
Mouth breathing in children often signals underlying nasal obstruction or dysfunctional orofacial habits. Left unaddressed, it can lead to facial deformities, dental issues, and developmental challenges. However, with timely multidisciplinary intervention—including medical treatment, surgery when needed, breathing retraining, and orthodontic care—many adverse outcomes are reversible or avoidable. Parents should seek professional evaluation if mouth breathing is frequent or accompanied by related signs.

📚 References

✔ Masutomi, Y., Goto, T., & Ichikawa, T. (2024). Mouth breathing reduces oral function in adolescence. Scientific Reports, 14, 3810. https://doi.org/10.1038/s41598-024-54328-x
✔ Zhang, J., Fu, Y., Wang, L., & Wu, G. (2024). Adenoid facies: a long-term vicious cycle of mouth breathing, adenoid hypertrophy, and atypical craniofacial development. Frontiers in Public Health, 12, 1494517. https://doi.org/10.3389/fpubh.2024.1494517
✔ Zhao, Z., Zheng, L., Huang, X., Li, C., Liu, J., et al. (2021). Effects of mouth breathing on facial skeletal development in children: a systematic review and meta-analysis. BMC Oral Health, 21, 108. https://doi.org/10.1186/s12903-021-01458-7
✔ Connecticut Children’s. (2025, July 15). Mouth Breathing in Kids: When to Worry and What You Can Do. Connecticut Children’s.
✔ Healthline. (n.d.). Mouth Breathing: Symptoms, Complications, and Treatments. Healthline.
✔ Verywell Health. (2023, January 24). The Effects of Being a Mouth Breather vs. Nose Breather. Verywell Health.
✔ Verywell Health. (2024). Why Mouth Breathing Poses a Risk to Your Health. Verywell Health.

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