The soldering temperature for orthodontic silver solders is between:

Silver-based solders are used when a low-fusing point is needed for soldering onto stainless steel or other base metal alloys. Orthodontic appliances are commonly soldered using silver-based solders. In general, the resistance of silver solders to tarnish is not as good as gold-based solders. The silver-based solders are composed of silver (10 to 80 wt%), copper (15 to 30%) and zinc (4 to 35%), with  some products containing small percentages of cadmium, tin or phosphorus to further modify the fusion temperature. The formation of the silver-copper eutectic is responsible for these solders to range from 620° to 700°C, which is slightly below those of gold-based solders. This difference is important in  the soldering of stainless steel.