A couple years ago I went through this with my daughter who was the same age and needed a ton of dental work. After insurance and over the span of about two years it was $6K worth of work, and all on baby teeth. I did have an initial reaction of "These teeth aren't even important, right? Root canals and fillings on baby teeth that will fall out soon, is this necessary?" But they explained why it was necessary and what problems it could possibly cause with her overall dental health and her future permanent teeth. The anesthesia that was required because of the extent of the work and how scared and impatient she was isn't something I really thought about at the time; they're professionals and know quite a bit about dental treatment requirements, and the anesthesiologist at the hospital where the treatment was administered surely knows a lot about anesthesia and probably has all kinds of training and certifications. I don't know anything about that stuff.