Wichelhaus A, Brauchli L, Ball J, Mertmann M. Mechanical behavior and clinical application of nickel-titanium closed-coil springs under different stress levels and mechanical loading cycles. Am J Orthod Dentofacial Orthop 2010 May;137:671-8. The affiliation shown for the first author, Andreas Wichelhaus, was out of date. It should have read:

Professor and chairperson, Department of Orthodontics, Munich University Medical Center, Munich, Germany. Andreas Wichelhaus and Lorenz Brauchli had equal contributions to the article.