Twin Block Appliance
A two-piece removable functional appliance with interlocking bite blocks that postures the mandible forward to treat Class II skeletal discrepancies.
Full Definition
Developed by William Clark in the 1970s, the Twin Block appliance consists of separate upper and lower removable components fitted with acrylic bite blocks angled at 70°, which interlock when the patient bites together to maintain a forward mandibular posture. It is one of the most widely used functional appliances in contemporary practice. Editors will encounter the name spelled as 'Twin Block' (two capitalised words), 'twin block,' or 'Twin-Block'; house style should be standardised. It should not be abbreviated to 'TB' without first defining the abbreviation, as 'TB' commonly abbreviates 'tuberculosis' in broader medical literature.
Usage
Usage note: Avoid abbreviating to 'TB'; always capitalise 'Twin Block' as a proper noun referring to Clark's design.
In Context
- "The Twin Block appliance was selected over the Herbst appliance because of the patient's younger age and anticipated compliance." — Treatment planning document
- "Studies comparing the Twin Block appliance with fixed functional appliances report similar skeletal outcomes but lower compliance rates." — Meta-analysis introduction