1St Cavity Filled

Well I think that at the age of 4 if he felt pain he would have cried. The nitrous doesn't mask the pain it only makes you feel good and at ease. So he would be calm in the chair. If the cavity was very small the dentist may have just used a topical numbing cream to the tooth if not a shot. That plus the nitrous should have made it so there was no pain. He could still feel pressure and that may have bothered him a little. Also the nitrous doesn't mess with your memory so he does remember it but if he had no pain he probably doesn't have any reason to talk about.....like it wasn't scary or anything.

My daughter just had the same thing yesterday, except when they got in there the tooth actually needed to be pulled. They said I could watch if I was hidden because kids do better without seeing their parent. My child just turned 4 and she didn't even know what happened. They were great! On Monday we have to go back for more fillings. It's her back teeth. My child brushes everyday, but she also eats hard candy and we weren't brushing afterwards...so, no more hard candy for my kiddo. She bites and chews it, hench the cavities.
To answer your question I am sure he was just nervous, were you in the room? could he see you? was this his first visit? like other PPs if he was in pain I would think he would have been crying out.

my daughter just turned four and has had 3 fillings, on two visits. I don't believe in Nitrous, and the cavities were shallow, so they didn't have to use novacaine. She threw a fit because she wasn't in 'control', but the dentist was very good and stayed positive with my daughter and we continued to reassure her that it was just a little bit longer. My daughter is VERY articulate, and she even now will say that it did not hurt her teeth art all she just was made because we were holding her down so that the dentist could do her work as quickly and safely as possible. I felt horrible about it, but I would rather have held her down than have the cavities get worse, and painful. We scheduled a dental visit early this time, so that she will not have any cavities (we have horrible teeth, even though we brush; genetics I guess). That way they can do a cleaning and hopefully get her over whatever anxiety she may have. I might also add that the anxiety is because I took her to a BAD dentist who scared her and they weren't even doing any procedures. The main issue was that the dentist said "If you don't behave I will make your mom leave the room" so she then felt threatened and abandoned. I now have to reassure my daughter that I will NOT leave her. I think if this visit goes well, then I will let her go back on her own, now that we both know the dentist and I think my DD will be more comfortable now.

Having a tooth filled "can" be painful if you are not fully anesthetized...

That being said, I GUARANTEE you that if he had ANY pain at all at four years old...he would have let you know. Kids aren't usually the best for suppressing emotions.

Of course he remembers...nitrous doesn't put you in a deep sleep/coma, or anything near it. It just sort of makes you feel heavy and calm.

At four I am certain he is old enough to verbalize any problems or trauma he had or has over it...just ask him if you are concerned. He will be fine.

he probably will but the tooth will fall out at some point anyways

If you had a competent dentist and your child didn't cry, he probably felt no pain. That being said, YOU are the one who needs to be cool about this. Don't pass along your dental anxieties to your child. Make going to the dentist a positive thing. My parents were always positive with me, and I have never had fear, even when facing crowns & root canals.