Reproducibility of the CVM method: a reply.

Near the end of their letter, Brezniak et al quoted a sentence from our conclusion section and suggested that the conclusion is inappropriate. However, immediately preceding the quoted sentence, we wrote ‘‘Based on those findings, we might not be able to make definite predictions on the effect of these differences on the actual tooth movements. However, it is safe to conclude that different force systems produce different types of tooth movement; therefore, we would expect to see more vertical canine movement and less tipping of the adjacent teeth with passive ligation compared with conventional ligation.’’ Finally, we stated in our conclusion that the force system produced in this in-vitro study by passive self-ligation was more accurate because more consistent vertical extrusion forces (the desired force) and less mesiodistal or buccolingual forces (undesired forces) were generated. We assumed that AJO-DO readers would recognize that this is the first of many tests with the orthodontic simulator, and our data provided an example of its capabilities. It has taken 6 years to prepare and validate a 3-dimensional orthodontic force measurement tool that will be used for many tests to better understand a vaguely understood area of orthodontics. We continue to investigate the effects of the ligation method, and we are now gathering data, using a much larger sample size to be able to perform statistical tests. These data will be collected by starting the canine in the displaced position and ligating the teeth from the anterior to the posterior sequentially. We have been approached by many academics and clinicians with numerous interesting research proposals to use this device, which is giving us a unique view into the world of 3-dimensional orthodontic mechanics. We plan to start an internship program for those interested in using the University of Alberta orthodontic research laboratory to investigate specific orthodontic biomechanic applications as part of a degree program or simply out of curiosity. We thank the doctors for their input and look forward to more discussions as more evidence is published and made available to AJO-DO readers. Hisham M. Badawi Paul W. Major Edmonton, Alberta, Canada Am J Orthod Dentofacial Orthop 2010;137:444-46 0889-5406/$36.00 Copyright 2010 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2010.02.006