Answer

It is permissible to implant silver teeth. However, if the silver develops a stench in the mouth then gold will be permissible according to Imam Abu Hanifah (RA) (Fatawa Mahmoodiah p.218 v.5)

If the part made of gold or silver is such that it can be easily removed then zakat will be wajib. If the part is not easily removable like a fixed tooth or filling, zakat will not be wajib. (Jadeed Fiqhi Masaail p.121 v.1)

Only Allah Knows Best