Dentistry is a business. Surprisingly, dental clinic set-up costs aren't as high as you might think: chair units from a few £K and glues, pastes, disposables are all quite reasonable. It's the building and staff costs that are the bigger burden.
NHS dentists get set fees and you'll likely find that they just don't want to do certain jobs – either referring to a hospital or pulling a tooth rather than doing money-losing work. You'll also find that the main difference between NHS and Private might be the sophistication of equipment and simply more time devoted to a single patient – NHS dentists often run 2 chairs in parallel, hopping between the two while injections take effect or x-rays get processed.
I used to do basic dentistry on my animal patients – root canals and fillings to avoid extractions. It was uncommon enough that when I did do them then I'd take the extra time to make it nice – carefully selecting colour shades of filling pastes and properly polishing them down.
When I retired and moved down here I had a large pinned filling come adrift. I went to a local NHS dentist. The shabby building didn't bother me but I was more concerned with the dead flies in the light defusers. Even a shabby building should be clean. She wanted to extract the tooth and refused to discuss any other restorative ideas I offered. I just walked out, found a private chap and 9 years later still have a functional tooth.
My previous NHS dentist had been a good chap – just up the road from my own clinic and occasionally we lent each other stuff that was back-ordered but the other had in stock. I never had any reason to doubt his work.
Digital radiography is the way to go. OK so a higher initial cost. My own large unit could image anything up to an Irish Wolfhound and when i bought it 20 years ago cost £80K but after that it was a few pennies per pic compared to the nuisance, time and maintenance costs of wet film processing. Instead of 'do we really need to take an x-ray' it became 'if it might help take a pic' and we could charge less than before plus dead easy to send a DICOM file to a new vet if they relocated or for a second opinion.
pgk