Direct printed removable appliances: A new approach for the Twin-block appliance.

Removable appliances are an important part of orthodontic treatment. The Twin-block is widely used for Class II correction. Traditionally, an impression, bite registration, and mounted plaster casts are required to fabricate the acrylic appliance, which usually requires a specialized laboratory. This makes the process expensive and also time-consuming. This paper aims to present an innovative approach for the virtual design and direct printing of removable orthodontic appliances, particularly the Twin-block, that can be done in-office without the need for casts or a specialized laboratory.