Could switching from a dimmable to a non dimmable LED bulb have caused a light fixture with dimmer switch to fail?
To be clear... you still have a dimmer, rather than a switch? If so, that's your problem in all likelihood.  In terms of trouble shooting, if you know how to safely check the output of the dimmer, I'd bet you find out it's fried. Otherwise for 2 dollars, replace the dimmer with a switch.  Should take ten minutes and I bet that's your problem.