AIRWAY AND DENTITION – AN INTER RELATION
• A correlation exist between airway and dentition
• Obstruction in airway can cause skeletal and dental discrepancies leading to several systemic conditions like ADHD, Obstructive sleep apnea etc
• Close collaboration between different specialists, pediatrician, allergist, ENT specialist, orthodontist, speech therapist etc is necessary for the early detection and timely treatment of dysfunction
Upper airway consists of mouth, jaw, nasal passages, tongue, and throat. Breathing is an important human function. The healthiest and most effective way to breathe is through the nose. Nasal breathing aids in the proper development of the upper airway, skeletal and dental growth. The function of the nose is to take in air, which is then warmed, moistened, and filtered. Small amounts of nitric oxide will be present in inspired air before entering into lungs. It plays a key role in killing dust mites and helps reduce inflammation. But certain pathological changes in our body like enlarged tonsils and adenoids can result in obstruction of the upper airway leading to mouth breathing. Mouth breathing unfortunately provides none of the benefits of nasal breathing.
Mouth breathing directly affects dental health by causing drying of oral structures and decrease in saliva production. One of the functions of saliva is to neutralize acid in the mouth and flush away bacteria. So without saliva there is risk of decay and periodontal disease, the pathological inflammation of the gum and bone support surrounding the teeth etc. During sleep, mouth breathing decreases intra oral pH and make the oral environment acidic as compared to normal breathing. This lowered pH can lead to erosion of tooth surfaces, increased sensitivity of the teeth to temperatures and susceptibility to tooth decay. Equilibrium exists between the oral musculature and tongue, but in case of mouth breathing this balance is lost with more pressure on maxillary teeth by oral muscles unopposed by tongue leading to narrow maxillary arch. Characteristic features of mouth breathers is the “Long-faced Syndrome” which describes a long face appearance, dropped eyes, dark spots under eyes, open lips, narrow nostrils, weak cheek muscles, high palate, narrowing of the upper jaw and malocclusion. Beyond the dental implications, upper airway obstructions can lead to sleep disturbed breathing which causes headache, snoring, difficulty in sleeping, neck, jaw, or ear pain. Snoring and mouth breathing are two primary indicators of sleep disturbed breathing. Chronic diseases such as obesity, ADHD, asthma, anxiety, Alzheimer’s, type II diabetes, cardiovascular disease and obstructive sleep apnea develop from sleep disturbed breathing. All these contribute to a complex cascade of anomalies affecting the quality of life and life expectancy.
Pediatric mouth breathing is reported in 10-15% of children. The habit may interfere with the development of chest, since mouth breathing is not as deep as nasal breathing. This may in turn lead to postural defects when the muscles of the chest, back and neck do not function properly. This will alter the equilibrium of pressures on the jaw and teeth and affect both jaw growth and tooth position. In order to breathe through the mouth, it is necessary to lower the mandible and the tongue and extend the head. If these postural changes are maintained, facial height would increase and posterior teeth would supra erupt, unless there was unusual vertical growth of the ramus, the mandible would rotate down and back, opening bite anteriorly and increasing the overjet. Increased pressure from the stretched cheeks might cause a narrower maxillary dental arch.
Fig.1 Adenoid face
Fig.2 Narrow constricted maxillary arch
Fig.3 Increased overjet
Longstanding airway obstruction can lead to a disuse atrophy of the lateral cartilage of nose. This results in a slit like external nares with narrow nose. Some times after the airway obstruction is removed and a patent airway is established, the nose may collapse on inspiration making reconstructive surgery necessary
Abnormalities of the oral and nasal structures can seriously compromise speech performances. Nasal tone in voice will be evident.
Mouth breathing can also cause several general changes. The functional airway also creates proper amount of nasal resistance so that the diaphragm and intercostal muscles must perform work to create negative pressure to promote air flow into the lungs. With oral respiration the resistance is lacking and poor pulmonary compliance is seen. This gives appearance of a pigeon chest.
Mouth breathing can also cause low grade esophagitis. Since esophagus contains no mucous glands, the mucus from the nose and pharynx serves to lubricate the esophagus. In mouth breathers the oral pharynx is dry and the mucous collects often to be expectorated. This prevents esophagus essential lubrication leading to esophagitis.
Blood gas studies reveal that mouth breathers have 20% more carbon dioxide and 20% less oxygen in the blood.
Prevention and Treatment
Next comes the question, “How we can prevent or solve this?” The first step in identifying patients with an airway dysfunction is proper clinical evaluation. During the examination there should be an evaluation of facial form and symmetry, an examination of the nose, the tonsils and adenoids, the tongue, the teeth, and the soft and hard palates. Mouth breathing can be considered as a risk factor of malocclusion because they change the physiological balance of growth. The healthcare provider should evaluate for septal deviations, size of the inferior turbinates and nasal valve stenosis during the evaluation of the nose. It is necessary to intervene early on etiological factors of mouth breathing to prevent the development or worsening of malocclusion and, if already developed, to correct it by early orthodontic treatment to promote normal skeletal growth. For these types of problems close collaboration is needed between different specialists, pediatrician, allergist, ENT specialist, orthodontist, speech therapist etc. This will allow early detection and timely treatment of dysfunction and avoid worsening of already established malocclusion. All these ultimately result in normal airway functioning.
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