This is a yoke of a original Plateau dress in a private collection. It is done on trade wool. Often times the teeth used on these dresses were saved from older items and might be centuries old and passed down thru families. These dresses carried a tremendous amount of family prestige and pride to own one, as they indicated wealth, and the hunting capabilities of the men of the family. Not many owned these types of dresses composed of the real teeth.
Among the Crow people the "Elks Tooth" dress is a standard of wear....but again, many of the teeth are carved out of bone to represent what you see here.
Also on many of the old dresses you see teeth that have been etched and inscribed. Unfortunately I am unable to tell you what these mean. If they have a societal meaning or are individual meanings to the maker and wearer of the dress.