In orthodontics/ braces treatment, chin projection is also an important consideration. There are two aspects that determine the projection of a person’s chin. The first aspect is the amount of anteroposterior bony projection of the anterior border of the mandible. The second factor is the amount of soft tissue that covers that bony projection.
A significant unit of measurement that orthodontists use to refer to chin projection is called NB-Pg. It is calculated by the amount of bone projecting past the cephalometric NB line (a linear measurement in millimeters). The thickness of the soft tissue on the other hand, is a variable factor in chin projection. These two factors determine the total amount of chin projection.