I don't think we ever had a school dentist. We were terrified of the nit nurse. Being found nit-positive would have condemned anyone to social doom. Even a rumour of nit-positiveness was usually enough (horrible though it is to recount there was a girl called Fanny at my junior school, which in itself was curse enough, but she allegedly smelled and had nits – she probably didn't smell or have nits, but I suspect her life was hell and we let it happen because if it was her it wasn't us). The spectre of the nit nurse loomed darkly over our school career.
As boys, we were all also terrified by the nurse that held your balls and made you cough. I mean, what if she was like your gran? Or if she's well, you know, nice and something happened down there? Or even worse, if she was like your gran, but you inadvertently started to think about Elizabeth O's ineffably pert breasts?
That said, I don't recall this ball-grabbing nurse putting in an appearance, so I think she was an apocryphal school terror.