Observational study of movements in lateral extrusion

This is a report of an “observational study” of tooth movement during the course of extrusion of upper laterals with aligners. Pure extrusion along the long axis is a most difficult movement for the aligner. Digital image data were collected from volunteer patients in a private practice setting, throughout the treatment period. Compliance of the enrolled subjects has been excellent. Their serial CBCT data were analyzed for the trajectory of tooth crowns and roots. The small sample data exposed a non-linear movement pattern both for the root and the crown. We termed this motion “wobbling.” The pattern of wobbling was not consistent across the subjects. Understanding the causes, directions, and magnitude wobbling may be expected to instigate novel algorithms for programmed aligner appliances.