Hugo De Clerck is a graduate of the Rijksuniversiteit Gent’s orthodontic program, he received his PhD in 1986 and he maintains a private practice in Brussels. He received the European Research Essay Award in 1988. His research team received the Dewel Award for the highest- rated clinical research paper published in the AJO-DO in 2011. He has been Professor and Chairperson of the Department of Orthodontics at the Université Catholique de Louvain from 1989 to 2006. Currently he’s Adjunct Professor at the University of North Carolina at Chapel Hill. He’s a former President of the Belgian Orthodontic Society and Fellow of the Royal College of Surgeons of England. His main research interests are in skeletal anchorage, biomechanics and orthopedics. He lectured extensively on these topics throughout the world.

Title of Talk

Rotations of the Maxilla and the Occlusal Plane: the Key to Successful Orthopedics


Rotations of the occlusal plane not only affect the vertical dimension of the growing face but also the anteroposterior relation between upper and lower jaw. Conventional tooth born class III orthopedics often result in upper molar extrusion and posterior rotation of the mandible, with increase of the length and convexity of the face, which sometimes is wrongly interpreted as a restraint of mandibular growth. Furthermore, an anterior or counter clockwise rotation of the palatal plane, by the line of force passing below the center of resistance of the zygomatico-maxillary complex, may also result in a downward movement of the upper molars. These maxillary rotations can be altered by changing the angulation of the orthopedic force and it’s perpendicular distance to the center of resistance, or by adding an extra moment of force. Finally the moment-to-force ratio of the resulting orthopedic force system applied to the upper jaw will determine the direction of the maxillary rotation, and the subsequent rotations of the occlusal plane and the mandible.