Physiologic and Dentofacial Effects of Mouth Breathing Compared to Nasal Breathing

A change in the mode of respiration, such as mouth breathing due to an inadequate nasal airway, could affect craniocervical posture, maxillomandibular relationship, and position of the tongue. This in turn could cause changes in dentofacial growth and positions of the teeth. The reported dentofacial and physiologic changes range from long anterior facial height, a retrognathic mandible, an open-mouthed posture, and extended head position to intraoral ramifications such as open bite, increased overjet, deep palatal vault, halitosis, increased caries, and gingivitis. These changes depend on the frequency, severity, and duration of the action as well as other factors such as genetic features, variability in functional demands, and age. Treatment of patients with a diagnosis of mouth breathing needs to be a conjunct effort between otolaryngologist, pediatrician, and orthodontist. Etiology is the key factor in establishing a treatment plan. To determine the etiology, objective evaluation of mouth breathing is important. If the cause of mouth breathing is obstructive, elimination of the obstruction is necessary to prevent abnormal facial and dental growth. In cases of obstructive adenoids and tonsils or allergic rhinitis, surgical or medical treatment is frequently indicated. Favorable changes in dentofacial structures and head posture are seen in these patients, especially when treatment is performed at an earlier age. Some of these patients may further need orthodontic treatment if they have already developed malocclusions. Depending on the severity of the malocclusion, the orthodontic treatment plan may include myofunctional therapy, maxillary expansion, use of functional appliances, dentofacial orthopedics, or orthognathic treatment.