A twin block is an

orthodontic Orthodontics is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, and misaligned bite patterns. It may also address the modification of facial growth, known as dentofacial ...

appliance developed by William J. Clark whose purpose is to lengthen the

lower jaw In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

by posturing it forward. If the jaw is growing during treatment, it naturally grows at a faster rate; otherwise the appliance is useless. Treatment time varies, but is generally around 9 months. Twin Blocks can also be used to cure an

overbite Overbite is the extent of vertical ( superior-inferior) overlap of the maxillary central incisors over the mandibular central incisors, measured relative to the incisal ridges. The term overbite does not refer to a specific condition, nor i ...

, which can mean treatment may be slightly longer. If this is the case, treatment can vary from 6 to 11 months.

References

Orthodontic appliances {{Dentistry-stub