Yikes, that’s interesting. I’m in Med and myself and many of my classmates routinely miss lectures, labs, etc in order to attend work. There are some (fairly minimal) compulsory components of the course, but as long as you’re passing/handing assignments in, etc, no one (and especially not fellow students who will share notes/be supportive etc) frowns upon it. Is this a Dent thing? Or more specifically a CSU Dent thing? I, for one, couldn’t study Med without also working. I’d be bankrupt!
I think to clarify (IMO at least) the biggest thing that a dental student shouldn't miss is simulation labs - especially in the earlier years (these are labs where you work on fake people/teeth for all you non-dental people out there or to be dent students). These labs are there to develop hand dexterity, instrumentation use and just getting a general feel of sitting with a straight back and working on a model. They're normally compulsory anyway but unless you're sick enough that you physically can't get out of bed to go to university it's best to go as there aren't many chances available for catchup. Eg, in one lab you might be drilling out a carious tooth and the next session you're doing a Class II box preparation and restoration - it's hard to fit in the previous class activities into the next class, etc.
Lectures and what not - sure you can catch up on.
Note: This is just my 2c as a dental student and not necessarily reflective of the CSU coursework as I've no idea how the CSU program is set out - maybe the lectures there are just as important as the lab work?!