Dentists, why such a price difference

[Harriet1216]

I need root canal treatment and a crown. I see that an NHS dentist charges about £280 for this, but I have been quoted £850.
I can't understand why the same treatment can generate such a vast price difference.
The price really puts me off having the work done.

Charges for NHS work are capped, private are not.

The NHS limits what materials can be used. Private dentists are able to choose to use superior (more expensive) materials. The dentist will also make a profit from private work which they won't on NHS treatments

Assuming you're in England, NHS dentistry has three levels of treatment charges, the £280ish one being the highest. Some treatments will cost less than the charge, some far more. The same principle applies to prescription charges.