Malocclusions are in part hereditary but environmental factors, including factors related to breathing and facial trauma, may play a significant part in the development of the condition.
Certain types of malocclusion may predispose the patient to jaw and facial pain.
Severe malocclusions
In traumatic deep bite, the lower front teeth bite into the roof of the mouth instead of on the upper teeth, or the upper front teeth bite into the gums of the lower teeth, and the condition may, if left untreated, cause ulceration and pain in the palate and weaken the upper supporting dental tissues. Pain in the masticatory muscles is also more common in these patients. Deep bite is also often accompanied by distal bite which results from the lower jaw falling markedly behind the upper jaw. It is important to treat deep bites, and particularly ones associated with distal position of the mandible, before the end of the child's growth.
Lateral and anterior cross bite, where one or several of the upper teeth are inside the lower teeth, may disturb both the movement of the lower jaw and the development of the temporomandibular joints (TMJ) during the growth phase. This has often been shown to be the cause of TMJ and masticatory muscle disorders. A cross bite should therefore be corrected during the child's growth phase as soon as it is noted, and the child's ability to cooperate is adequate.
Severe open bite, where only the molars come into contact, may cause pain in the masticatory muscles, jaw fatigue, difficulty eating and tooth wear.
Patients with Class III malocclusion, i.e. the lower jaw bone is more prominent than the upper jaw bone, are more prone to masticatory muscle disorders.
The primary aim should be to treat all the above serious malocclusions during the child's developmental years. In the most severe cases, or if growth has already been completed, malocclusion may either be treated conservatively with orthodontic treatment or by orthognathic surgery which involves, in addition to the orthodontic treatment, one or both jaw bones being realigned to provide a functional bite.
Trauma to the face or jaw area may result, for example, in asymmetric growth of the TMJs thus causing severe malocclusion. After facial trauma, an orthodontist should monitor, and treat if necessary, the bite of the child until the end of the child's growth period. In the most severe cases it will not be possible to correct these malocclusions either with conservative orthodontic treatment alone, but they are corrected with orthognathic surgery combined with orthodontic treatment as part of multidisciplinary collaboration when the growth period is completed.
Problems caused by abnormal position of the teeth and misalignment of the jaws
Tonsillar tissue in the nasopharynx
Hypertrophy of the adenoids and tonsils may affect the mandibular development to allow for more room and thus worsen the malocclusion of the teeth. In these cases, the orthodontist should consult an ear specialist in order to optimise both the malocclusion treatment and the respiratory function.
Sleep apnoea
Unlike in adults, sleep apnoea (i.e. repeated cessation of respiration during sleep) in children may cause hyperactivity and restlessness. Sleep apnoea in children can usually be cured with tonsillectomy and adenoidectomy. Additionally, orthodontic treatment may be required to steer mandibular growth and, as necessary, to broaden a too narrow upper jaw. Both methods of orthodontic treatment widen airways and hence alleviate possible sleep apnoea and also have a prophylactic effect on the development of sleep apnoea.
In adults, the symptoms of sleep apnoea include daytime tiredness, depression, sudden sleep episodes, loud snoring and nightly interruptions of breathing.
The first-line treatment of obstructive sleep apnoea in adults consists, in addition to weight loss, of positive pressure ventilation, i.e. continuous positive airway pressure (CPAP) ventilation Sleep Apnoea in the Adult. A second-line treatment approach consists of a dental device supplied by an orthodontist. In mild sleep apnoea, a dental device (mandibular advancement device) can at discretion be considered as the first-line treatment in addition to conservative treatment. In the most persistent cases, orthognathic surgery may be considered. The referring doctor should ensure that the patient has a sufficient number of healthy teeth and treated dentition to retain a dental device.
Speech disorders
The relationship between the abnormal position of the teeth and speech disorders has not been fully explained. The faulty pronunciation of the s-sound has been shown to be linked with an anterior open bite (vertical space between the upper and lower front teeth when the back teeth are closed).
Rheumatoid arthritis
About 50% of children with rheumatoid arthritis will develop damage to the TMJs by the age of 16 years.
The opening of the mouth may become restricted and the range of motion of the lower jaw limited. The TMJs may be painful with crepitus. Additionally, eating and tooth brushing may be painful.
If the lesion is unilateral, the lower jaw will deviate to the affected side when opening the mouth.
Bilateral damage may lead to mandibular deficiency, convex facial profile (”bird face” deformity), deep antegonial notch (depression along the posterior jawline) and an open bite. In such cases, also the pharynx may become narrower, which may predispose to sleep apnoea.
Concerning a child or adolescent with rheumatoid arthritis, it is important that the orthodontist, maxillofacial surgeon and rheumatologist work together to treat and monitor the development of the patient's bite throughout the growth period.
The condition of the TMJs in a patient with rheumatoid arthritis is defined on the basis of patient history, clinical examination, plain radiographs and, if needed, cone-beam CT and MRI imaging. TMJ arthritis is treated as needed with topical medication, oral analgesics, physiotherapy, jaw exercises and relaxation therapies, as well as with a dental device. Additionally, in inflammation of multiple joints or when the response to the treatment of TMJ inflammation is poor, one should consider starting systemic drug therapy for rheumatoid arthritis or modifying existing medication.
These developmental disorders are usually accompanied by problems with the bite, and treatment is either centralised at specialist centres or carried out locally under the supervision of the specialist centre.
Otitis media is more common in this population.
Multiple developmental disorders
Many syndromes, such as cleidocranial dysplasia or Pierre Robin syndrome, may be associated with malocclusions, the treatment of which may in severe cases require specialist intervention.
Arrangement of treatment
E.g. in the Nordic countries it is estimated that at least one fourth of children and adolescents in the growing age are in need of orthodontic therapy.
Malocclusions are usually treated by an orthodontist. The ten-point Treatment Priority Index (TPI) is used in some countries to score a developing malocclusion. The treatment of severe malocclusions, TPI 8-10, may be arranged in primary care. The most severe cases are treated in specialized units for oral and maxillofacial disorders.
References
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