The aim of the study was to design a bracket structure that features two parallel rectangular slots. This Twin-slots bracket separates the embedment of two archwires and therefore forms a force-acting area between the archwires and the slots, creating a large amount of force moment. With the tooth displacement being guided and controlled within the track of two archwires, some modalities of tooth movement that require heavy force moment, such as mesio-distal bodily translation, de-rotation and uprighting, could be manipulated efficiently. A variety of options in the combination of two different archwires mean they function independently but integrally to fulfil complex teeth repositioning, e.g. relieving severe crowding in anterior teeth while reinforcing the anchorage in the molars, and retracting the anterior teeth by one archwire performing labial-lingual tipping while the other adjusts torque. A case report was provided to demonstrate its clinical application. This design is a preliminary attempt and further improvement in the slot structures, such as the built-in prescriptions, should be the subject of further research.
Keywords: force moment, main and auxiliary archwires, twin-slots bracket