Biomechanical Considerations for Fixed Appliance Treatment and Aligner Treatment

Webinar Speaker

Professor Noriaki Yoshida
Professor and Chair
Department of Orthodontics and Dentofacial Orthopedics
Nagasaki University Graduate School of Biomedical Sciences

Abstract

In sliding mechanics with the fixed appliance, horizontal level of retraction force can be freely adjusted by attaching various lengths of power arms to an arch wire. If the horizontal level of retraction force for achieving controlled tipping, bodily movement, or root movement of anterior teeth is known and applied accordingly with different lengths of power arms, anterior teeth can be effectively and efficiently retracted, and its mechanics can be extremely simplified. However, sliding mechanics has some disadvantages, the most critical shortcoming being generation of friction, which would prevent the efficient tooth movement. Since loop mechanics is frictionless treatment system, the applied force is directly delivered to the anterior teeth without force loss. On the other hand, bowing effect is much more likely to occur as a result of low stiffness of the loop due wire span is long. Several methods will be proposed to reduce the vertical bowing effect during frictionless space closure. Lastly, biomechanics of aligner treatment will be discussed and solution for maximizing therapeutic efficiency and minimizing undesirable side effects will be considered.

About Speaker

Professor Noriaki Yoshida is the Professor and Chair of Department of Orthodontics and Dentofacial Orthopedics, Nagasaki University Graduate School of Biomedical Sciences. Professor Yoshida obtained his DDS from Nagasaki University School of Dentistry, Japan. He has experience working in Germany as well as Japan. He was also an honorary clinical professor in the University of Hong Kong.