and muscular hyperactivity probably play an important part in the development of
TMJ disorders in childhood.
Key Points
Orthodontic injury
- Teeth with blunted or thin roots have a greater risk of resorption during orthodontic
treatment. - Prolonged treatment with high forces increases the risk or root resorption.
- There is little evidence that malocclusion or orthodontic treatment are associated
with temporomandibular joint disorders. - There is no evidence of significant long-term periodontal disease associated with
orthodontic treatment. - Good oral hygiene and diet control are especially important during orthodontic
treatment. - Daily fluoride mouthwashes reduce enamel decalcification.
The commonest clinical symptoms in children and adolescents are clicking (10-30%)
and muscle tenderness on palpation (20-60%). Clinical signs such as reduced opening,
pain and movement, and tenderness of the joints on palpation are less frequent than in
adults. There seems to be no consistent pattern in the development of either subjective
symptoms or clinical signs during growth. Headache is common in children (girls
more than boys) and its prevalence increases with age. The connection between
headache, bruxism, hyperactivity of jaw muscles, and mandibular dysfunction is well
recognized and should not be missed.
Children with TMJ symptoms and those starting orthodontic treatment should have a
full examination for occlusion, tooth wear, mandibular mobility, TMJ function and
palpation, and jaw musculature function and palpation. One clinical symptom that has
consistently disclosed the presence of a TMJ dysfunction is reduced opening.
Treatment principles used in adults can be broadly applied to children and
adolescents, after taking into account the dynamic changes in occlusion in connection
with tooth eruption and facial growth. The majority of treatment is by activators
and/or splints. Occlusal adjustment is not generally undertaken in the young
permanent dentition as most occlusal displacement in growing individuals will change
with time. However, selective grinding may be necessary when a direct causal
connection is suspected. It may be difficult to motivate children and adolescents to do
jaw exercises, compared with adults. Training in one or two movements against
resistance is usually accepted.
The TMJ can also be affected by diseases or conditions which might influence
mandibular growth. The most frequent are juvenile idiopathic arthritis (JIA),
traumatic injuries, unilateral hyperplasia, and congenital aplasia. JIA affects the TMJ
in over 50% of those with the disease. This causes destruction of the condyles and
glenoid fossa leading to mandibular micrognathia, mandibular asymmetry, open bite,
abnormal bite, reduced opening, and loss of muscle strength. Traumatic injuries
involving the condyles can lead to abnormal growth and development and should be
followed closely.
Unilateral hyperplasia of the condyle, although rare, may occur around puberty. This