Elderly cat grinding teeth

I have a 17 year old cat whose teeth are not in the best shape (lots of plaque which is affecting her gums). I didn't realize dental care was a thing until recently, so I didn't do any upkeep since I got her at 2.5 yo (I promise I have taken good care of her otherwise, I just didn't know unfortunately.)

Recently she's been grinding her teeth. I took her in to my vet, and he said that every once in awhile her jaw gets misaligned which is why she's grinding. Because she's still eating and not showing any signs of pain, he didn't recommend taking action at this time, but to let him know if anything changes.

She does the grinding/head cocking every 10 seconds or so while eating, and I woke up this morning to her doing it even when not eating her food (I blend it into a liquid and she still does this.) Other than getting a second opinion from a vet, is there anything I can be doing for her so she doesn't do this? I'm not sure if cleaning would be advised for her age, and she already underwent surgery for breast cancer this year, so I'm not keen on putting her under again.