Abstract: An orthopaedic modular assembly comprises a housing component of rigid material providing a first passage, a second component in the form of a lingual pad support having a first arm adapted to form a sliding fit within the first housing passage and a second arm extending at an angle to the first arm and adapted to conform to the line of the one side of a patient's mouth and a latch associated with the housing component, whereby the first arm of the second component is held within the first passage of the housing component by the latch and is slidably adjustable relative to the housing component to any one of a plurality of predetermined latched positions. The sliding lingual pad component is locked simply and securely in the housing component and is able to be moved forward in precise increments relative to the housing as treatment progresses.