PRE-ADJUSTED EDGEWISE APPLIANCES [PEA]

Orthodontics has undergone a remarkable evolution in fixed appliance therapy since the pioneering contributions of Edward H. Angle, who introduced the edgewise appliance in 1925. This innovation enabled comprehensive three-dimensional control of tooth movement and established the foundation for modern mechanotherapy. Subsequent decades witnessed refinements by Tweed, Holdaway, and Strang, focusing on anchorage preparation and wire-bending techniques.A paradigm shift occurred with Lawrence F. Andrews' Straight Wire Appliance (1970), which incorporated the Six Keys to Normal Occlusion into bracket design. By pre-programming torque, angulation, and in-out values into individual brackets, Andrews significantly reduced the need for extensive archwire bending. The straight wire concept was later enhanced through Roth's prescription, which emphasized overcorrection, gnathological principles, and the use of Tru-Arch forms to improve functional stability.In the 1990s, McLaughlin, Bennett, and Trevisi (MBT) introduced a third-generation system tailored to light, continuous forces and sliding mechanics.