Yes. Your horse will be given a sedative prior to getting it’s teeth floated. While the horse will be sedated, it will still be able to stand on all fours.
Just like humans, horses will differ in the amount of time it takes for a sedative to wear off. Typically a horse will feel normal again in about an hour’s time. It is important to not give your horse grain or hay until the sedative has completely worn off as it can affect the horse’s ability to swallow.