title: Evolution of treatment mechanics and contemporary appliance design in orthodontics: A 40-year perspective.
abstract: Until the early 1970s, successful treatment with the Begg technique and the Tweed edgewise technique required tedious wire bending. The introduction of Andrews' straight wire appliance changed that, and it was one of the most significant contributions in the history of orthodontics. The straight wire appliance significantly reduced the amount of wire bending and also brought along other options in treatment mechanics. Retraction of the canines with elastic chains and ligature wires became more common. Sliding mechanics in place of closing loops became the method of space closure for a significant number of clinicians. Edgewise force levels were initially used to close spaces; however, it was soon observed that lighter forces were more effective with sliding mechanics. Along with these changes, it became apparent that compensation in the appliance was needed, depending on the type of malocclusion and particularly with varying extraction sequences. Various appliance designs were developed to accommodate changes in mechanics and force levels. These modifications improved tooth positions at the end of treatment as long as the brackets were properly placed. These major changes in appliances, force levels, and treatment mechanics can be traced back to the work of Dr Lawrence Andrews and the straight wire appliances.
authors.affiliation: Richard P. McLaughlin is a graduate of the University of Southern California, Dept. of Orthodontics, and is in private practice in San Diego, California. He is currently President of the Edward H. Angle Society and is the founder of The McLaughlin Program, a private 2-year postgraduate orthodontic course. Electronic address: rpmclaugh@aol.com.
authors.forename: Richard P
authors.initials: RP
authors.lastname: McLaughlin
authors.affiliation: John Bennett is a graduate of the UCL Eastman Dental Institute in London, England. He was in private practice for many years in London. After a period of teaching at European University College in Dubai, he has returned to the UK to resume clinical work. He has authored or co-authored 7 orthodontic textbooks.
authors.forename: John C
authors.initials: JC
authors.lastname: Bennett
mesh_terms: D001696:Biomechanical Phenomena; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D016382:Orthodontic Appliance Design / Q000266:history*; D009969:Orthodontic Wires / Q000266:history*; D009971:Orthodontics, Corrective / Q000266:history*