Direct fabrication of power arms

An appliance for placement on teeth of a patient, the appliance comprising:

• a plurality of power arms comprising a first power arm having a first connection point for connecting to a shell or tooth and a second power arm having a second connection point for connecting to a shell or tooth;
• a connecting structure coupled to the first and second power arms to apply a first force to each of the first and second power arms;
• and
• a counter-force connector coupled to the first power arm and extending toward the second power arm to apply a second force to each of the first and second power arms opposing the first force when engaging the second power arm,
• wherein the connecting structure and the counter-force connector are coupled to the first power arm at respective locations separate from the first connection point, the connecting structure is coupled to the second power arm at a location separate from the second connection point, and the counter-force connector, when engaging the second power arm, contacts the second power arm at a location separate from the second connection point.