Madam,pfm means it's basically made up of metal,but will be having ceramic layer coating on it so that its looks like natural.zirconia is a complete ceramic cap.function wise both are same,only the material differs and even in price wise pfm Wil be almost half of zirconia.zirconia gives the best look
Next Steps
at the end of the day,it's patients choice to select which cap they want depending on the financial as well as esthetics aspects.
Health Tips
both zirconia and pfm comes with a warranty from the lab.if look matters to u,then u can opt of zirconia caps n front teeths,and pfm for back teeths,n that way it becomes economical also...