Abstract: A lingual orthodontic appliance system for edgewise orthodontic therapy incorporating twin type brackets with single bracket interbracket width. Brackets for anterior teeth incorporate three tie wings in T-shaped orientation and brackets for bicuspids have two pairs of twin tie wings. Molar tube brackets retain the terminal extremities of the archwire and provide hooks for closing loops, tie-back loops, etc. In each case the archwire slot opens toward the occlusal permitting simple and efficient insertion and positioning of the archwire within the various brackets of the appliance system.