By now, you should be familiar with our case parameters. (They got a slight visual refresh recently, so you might want to download a new copy.)
The case parameters provide guidelines to help you estimate how suitable a case is for clear aligners, and how predictable you can expect the movements to be.
For instance, a few millimeters of crowding can usually be corrected easily and quickly with clear aligners, while a case requiring lots of extrusions is likely to be much more difficult.
But how do you know exactly how much crowding there is? What do you measure to determine the amount of overjet?
This is probably basic stuff for many of you, but if you need a refresher, you may want to have a look at the American Board of Orthodontics' Discrepancy Index.
The ABO originally developed the Discrepancy Index in 1998, and its been refined in the years since. It provides standardized methods for measuring types of malocclusion, and also offers a simple point scale for determining the severity of a case. They've produced a PDF guide and a series of YouTube videos demonstrating how to measure and identify common types of malocclusion.
We don't currently use the ABO Discrepancy Index ourselves, but we thought some of you might find this a useful resource regardless.