Will you be able to feel "regular" anesthesia the dentist injects you with if you have had laughing gas?

Yes, but....: While under the influence of laughing gas, you can still feel what is being done, but the benefit of the gas is that you rally won't care. It's amazing, but true!

Minimal: Breathing n2o before an injection will probably reduce the discomfort of that injection. That said, almost all dental professionals use tiny needles and topical anesthesia in the mouth before the injection. Either way you'll do fine!

Possibly: You may still feel a small pinch depending on the area injected.

Not really: Pain requires you to consciously process a noxious stimulus. Your nerve endings will detect the needles, but the nitrous oxide will make it difficult for you to process that information. What this means is you can't have pain if you can't feel the pain?

You may: Nitrous oxide affects people in different ways, with some people feeling very relaxed and comfortable, and others reporting feeling no different. Unfortunately, there are some areas of the mouth that are more sensitive to injections than other areas, and some patients may be able to feel the injection.