The Quatro appliance: a removable aligner with a changeable labial bow.

Lower labial segment irregularity is a feature that is presenting more frequently as greater emphasis is placed on aesthetics than ever before. The authors report on a removable appliance that is easy to construct and use and is designed to deal with mild labial tooth irregularity. In cases of crowding the aligner can be used in conjunction with inter-proximal stripping. The device incorporates a removable labial bow attached bilaterally to a sliding lock. This lock permits the addition of sectional archwires to the labial part of the appliance. The versatility of the aligner allows round and rectangular wires of different materials and dimensions to be placed with or without bends.