Novel concept for the multidimensional measurement of forces and torques in orthodontic smart brackets

This paper reports a novel sensor concept to measure the six components of the forces and torques applied to smart orthodontic brackets. The concept is demonstrated using a packaged CMOS based sensor chip and a novel test setup to measure the six forces and moments applied to a smart bracket. By measuring the stresses in the plane of a sensor chip inside the bracket, it is possible to extract the forces and moments externally applied to the bracket. The sensor chip contains three CMOS piezoresistive stress sensors making it possible to separate one force and two moments with the range typical for orthodontic therapy