Functional appliances are typically removable appliances that are
designed to hold the lower jaw forwards for the correction of upper
incisor protrusion in growing patients. The ideal time to use a
functional appliance is during the pubertal growth spurt to help
take advantage of the normal facial growth that is already
occurring.
The Twin Block functional appliance
Functional appliances are constructed after taking a dental
impression of the teeth and can consist of a single component or an
upper and lower component fitting over the teeth. They can produce
spectacular results by reducing upper incisor protrusion and work by
a number of mechanisms including retraction of the upper incisors,
advancement of the lower incisors and a small degree of forward
growth of the lower jaw. They are designed to be worn at all times,
apart from sleeping, and typically produce the desired result within
9-12 months if compliance is good. Functional appliance treatment
will often lead to a correction of the bite and is often followed by
a course of fixed appliance treatment to fine tune tooth positions.
Before and after functional appliance treatment. Note the large
reduction in upper incisor protrusion.