Hi S. - I have had both of my boys "knocked out". My oldest was almost 4 when he was the first time for dental work. The 2nd time was for tubes in his ears. My youngest has been out 3 times (thumb surgery, MRI/CT scans, and ear surgery). It can be a scary event for kids but you are already on the right track by talking to her about what to expect. Is the hospital where this is going to happen close to your home? If so ask them if you can give her a tour (during non busy time) and walk her through the process (you may not even need to look at the operating room as she will be asleep & wont know she was there). Tap into your dentist (hope they are a pediatric one), many times they have videos/books that you can share with your daughter. Also check out the library for books on this subject. You will never know for sure how she will react to the anesthesia but more than likely she will be fine. For my boys, they took with them special stuffed animal (many times the hospitals give them special presents too). The hospitals (we have worked with 4 different ones) also were great & gave the stuffed animals a medical ID bracelet just like our kids got. When my youngest had surgery on his thumb the hospital also put a bandage on his bear. It really helped him to deal with the bandage & he ended up thinking it was "cool".
What to expect... more than likely after you arrive at the hospital: you will get her changed into hospital clothes (vitals will also be taken), have her go potty, and then drink a fruit flavor liquid (that will help her get sleepy). Let her know that you are there and love her & will always be there, she is going to rest/get sleepy for a little bit but you will be there when she wakes up. I have even been able to carry one of my boys to the operating room. One of the biggest things us Moms need to do is keep a good happy face, don't get teary/crying or sad (don't fake happy!!) - kids pick up on that so fast!. Your attitude will help make this a positive event for your daughter. When she starts to wake up the staff will bring you back to be with her. Each kid wakes up different (I have had my kids wake up wonderful & also upset), but again our attitude will help them adjust quickly. You can usually sit in a rocker with them as they wake up (the vitals machine will stay hooked up for a while). After they can go potty & drink some juice or even eat a little, you can take them home. Depending on how each kid is some stay sleepy off & on for the day, others bounce back right away (bring a change of clothes for accidents or if they puke). There is no one way for kids (even repeat kids). If you have any questions, write them down, talk to the dentist, doctor & hospital and follow the directions given. After you are home call them with any concerns, even if it is after hours, they expect & want calls.
It can be a frightening thing for both parents & kids but it will be OK. Yes, there are risks (and they will talk with you about those) but there are risks in just driving down the road. Trust the process & take it one step at a time and your daughter (with your prep help) will make it through with flying colors. God Bless