White fillings are made of resin composite and have become quite advanced now lasting nearly as long as silver fillings. The advantage is that they are aesthetic and blend in well with natural teeth. The method of bonding resin to a tooth has evolved to its 7th generation and when placed in dry conditions is excellent.
Silver fillings are made from an amalgam(mixture) of different metals including silver, copper, tin and mercury. The mercury content in these fillings raises a lot of controversy as in itself it is toxic. Many patients decline the use of these as a matter of health and looks. The advantage of this type of filling is that they are very durable.