I am a pediatric dentist, so hopefully I can shed a little light on your question.
When I evaluate a child, I treat each child individually and make a determination on what the best type of treatment is for that specific child. It also depends on the amount and type of treatment that needs to be accomplished. The goal is always to prevent any dental fear from developing and complete the treatment safely and comfortably and it really depends on each individual child.
In other words, one 5 year old may need laughing gas, another may need general anesthesia, and another may only need gentle TLC!
If you are seeing a pediatric dental specialist, then I would hope that they made the determination of what the best approach is to treat your daughter.