You can get away with a lot to be honest without even HAVING to tell them. For example, you would need a baseline scan. Takes 5 minutes. Dental appointment should cut it. You're literally in and out.
You will then need a further scan to check if egg collection can take place. Those pesky wisdom teeth really are causing you a problem. A really bad problem. Keeping you awake all night. You need to go for an xray. Again, this is literally a 5 minute job. Offer to have an early lunch hour. That way, you are not taking any time off at all. You are simply rearranging your working day. And as for them finding out, unless you tell them how could they find out? It's not as if they will phone your dentists. In fact, they won't even know who your dentist is.
An egg collection takes roughly the same length of time (and time off work) as a wisdom tooth extraction (if you get what I'm saying - oh, and you need them removing pretty much immediately because one of them is pressing on a nerve) plus, the following day you could've had a reaction from the anaesthetic and you're feeling really sick. You could drag that out an extra day or so for the embryo transfer and after that you don't really need any time off work.
This is what I plan on doing for my next 'go'...I pretty much have the permission of my office manager to do so.
"Next time," she said, "just don't tell anyone what you're doing. You could just have a lot of dental appointments!"