Hiya,
Do check your contract of employment, your employer needs to state clearly the conditions of your engagement as a trainee. You need to check if you are on what is called a 0 hour contract where they don't have to provide any work at all.
It isn't unusual to ask nurses to take time off at the same time as the dentist - this does happen a lot, I worked in a practice previously where the dentist would take two weeks in the summer and it was a good idea to take the same time where possible.
If you are concerned, do contact ACAS for independent employment advice. They can be really helpful.
Hope this helps, even just a little.
Don't let this put you off of dental nursing, it is a highly rewarding career and is totally worth the late nights, early mornings, puke on your top and saliva/bits of tooth in your hair because all the moments of brilliance and happy patients with better oral health outweigh all the bad stuff x
