My dog is groggy after dental cleaning. When should I worry?

It depends quite a bit on what drugs and doses were used for anesthesia, so unfortunately it's difficult to give a good answer to this question without being able to look at his medical record. But in general, for most anesthetic procedures, it's not uncommon for many dogs to remain somewhat groggy or drowsy for up to 12 hours or so afterwards - my rule of thumb for owners at our clinic is that their pet should be acting normal again by the following morning, but not to worry overly much if they are a bit sleepy or "off" for the rest of the afternoon or evening after going home. However, the pet should be able to get up and walk around, eat and drink without problems, etc. - if they are groggy to the point of being unresponsive or unable to stand, this is not normal.

If you are concerned about Falkor, the safest course of action would be to call your vet's office and describe how he is currently acting - they should be able to tell you if this is reasonable, based on their anesthesia protocol. If he is unresponsive, having difficulty swallowing, or seems to be getting worse over time, I would take him back to your vet or your nearest emergency clinic to be checked.