Dentist recommends stronger amalgam: not available NHS

[Paul Hodges]

My mother recently had a filling, the dentist convinced her to have this done privately so that a stronger material could be used that isn't available on the NHS... does this sound plausible, are there stronger materials that are unavailable on the NHS? It looks just like the ordinary amalgam, has my elderly mother neen taken advantage of? Thankyou for any advice.