Abstract: A controlled layer of base mass is uniformly applied to a dental crown or bridge 10 of noble metal alloy by electrophoretic separation in a glass container 14 after an intermediate layer of galvanized zinc or tin is first applied in a container 13. The intermediate layer may be omitted if the crown or bridge is made of a non-noble metal alloy. The containers are provided with semi-cylindrical cathodes 15, 16 coupled to an electrical supply by jack plugs 19, 20. The crown or bridge serves as the anode and is held by tongs 21, 22 connected by cables 23, 24 to the power supply, and both the magnitudes and durations of the bath currents are adjustable. The liquid suspension of the base mass in the electrophoretic bath is maintained by a magnetic stirrer 27.