Every rabbit is different, but generally if they aren't eating adequate amounts by the next day(no more than 24 hrs from the last time they ate normally pre surgery) then it's necessary to talk to your vet first thing in the morning, as you will need to start regular syringe feeds. If this wasn't just a trim but an extraction, syringe feeds are likely going to be necessary for a few days at least, as it could be difficult for your bun to chew and get used to chewing with the missing teeth. If your bun is used to eating leafy greens/herbs(cilantro, parsley, dark leaf lettuces, carrot tops, etc), you might have the best luck getting your bun eating again starting with those. That's usually what my buns will go for first after surgery.
It's also very important to keep your bun warm while the anesthesia is working itself out of the buns system. Anesthesia can cause a bun to get hypothermic, and a cold bun won't be inclined to eat. So I would provide a rabbit safe heat pack or heat source. I will usually feel their ears to monitor their body temp. If the ears are warm then body temp is usually good. If the ears are cold, bun probably is too cold and needs help to keep warm.
Did the vet provide take home pain meds like meloxicam, to give to your bun? That is important for a bun to have post procedure, especially if it was more invasive like an extraction. A rabbit in pain isn't likely to want to eat, especially if it's their mouth that's hurting.