Sheldon Friel memorial lecture 2007: myths and legends in orthodontics.

Opinions and procedures, which are incorrect or invalid but continue to exist, are discussed. Eight seldomly criticised subjects have been selected which are relevant for the theory and practice of orthodontics. First, the idea that all individuals have or can reach an occlusion with contact between all opposing teeth is commented upon. Second, interest and preferences of editors and referees in the acceptance of manuscripts is clarified and the neglecting of published information explained. Third, the reliability of conclusions drawn from lateral roentgenocephalograms is reviewed in regard of the accuracy of commonly used bony landmarks. Fourth, the interpretation of growth data concerning visual interpretation, error of the method and reliability of conclusions based on cephalometric data, is treated. Fifth, the need of lateral roentgenocephalograms and recently developed digital techniques for diagnostic purposes is evaluated. Sixth, the validity of facial orthopedics, and particularly its supposed contribution to the improvement of facial configuration and beauty is analysed. Seventh, the idea that the increase of mandibular intercanine width is the cause of the occurrence of mandibular incisor irregularities after alignment by treatment is challenged. Eight, the usefulness of traditional removable retainers as the Hawley and "wrap-around" appliance, is questioned and an approach and design, adapted to the change from banding to bonding of fixed appliances, is presented.