The present invention provides methods and systems including orthodontic tooth positioning appliances. The one or more guide rails of the printed circuit board include a ground trace on the top andor bottom surfaces of the printed circuit board. The techniques and compositions promote exothermic reactions during the welding process which reduce the energy otherwise required of the arc. One or more profile model parameters to be used in evaluating the one or more selected goals are selected. The particles can be blended with oxidant particles to form energetic powder that releases chemical energy when the buffer layer is physically disrupted so that the reductant metal core can react with the oxidant. The foam concentrate can be made at ambient temperature, is stable over time, can be easily tailored to achieve a desired foam stiffness and drain time characteristic over wide ranges, and can be easily diluted at ambient temperature to produce a foamable composition.