Angle’s class II malocclusion is type of orthodontic problem that indicates abnormalities in the tooth positioning as defined by Edward Angle. The condition is characterized by distal position of the lower jaw as compared to the upper jaw. The Angle’s class II malocclusion is associated with two major factors – skeletal problems and dental disturbances. The condition is further divided in to division I and division II subtypes.
The most common symptom associated with Angle’s class II malocclusion is forward placement of upper anterior teeth. The forward placement of the teeth leads to an increase in the horizontal space (overbite) between the upper and lower incisors. The skeletal changes associated with Angle’s class II malocclusions include protrusion of the upper jaw bone, retrusion of the lower jaw bone and combination of both.
The facial profile of the patients with Angle’s class II malocclusion appears to be convex when viewed from the side . The patients also exhibit an abnormal muscle activity pattern around oral musculature. The abnormal functioning of muscles leads to narrowing of upper dental arch and posterior cross bites.
Generally the patient exhibits short upper lip leading to lack of complete closure of both the lips. Patients also experiences a lip trap between the lower lip and upper anterior teeth.
The most probable cause of Angle’s class II malocclusion is genetic inheritance. The size, shape and position of the jaw bones are mostly determine by the genetic pattern and it is common to see the malocclusion running in families. The condition can also develop as a side effect of some drugs and radiation exposure during pregnancy. Abnormal positioning of the fetus during intra uterine life can also be one of the factors.
Trauma to the temporomandibular joint during birth and in postnatal life can lead to developmental defects of the jaws and may lead to this condition. Diseases such as osteoarthritis of the jaw joint or juvenile rheumatoid arthritis can also exhibit disturbances in the growth of the jaw bones. Radiation therapy can also be one of the causes of Angle’s class II malocclusion. Habits associated with this malocclusion include mouth breathing, abnormal swallowing patterns and thumb sucking.
The treatment of Angle’s class II malocclusion depends on the dental and skeletal involvement and age of the patient. In growing children the growth of the jaw bones can be directed in to a desired pattern by using orthopedic appliances. The deficit lower jaw can be corrected by the use of orthodontic appliances using myofunctional therapy. Face bows and headgears can be used to restrict the forwardly growing upper jaw.
Camouflaging the existing malocclusion by orthodontic movement of the teeth, without skeletal correction can be done in adult patients with mild forms of Angle’s class II malocclusion. To carry out the tooth movements, space has to be created in the dental arch by means of extraction of a few teeth. In adult patients the ideal treatment to correct the malocclusion is orthognathic surgical procedure by which the position of the upper or lower jaw segment can be corrected.