How about for cavities? I remember reading an article recently about major increases in the number of cavity related treatments because $$$. My kid has had multiple recommendations for cavities and I've got some suspicions about the absolute necessity of all of it.
Fillings are definitely a staple of the procedures a dentist would perform. The article does mention overtreatment, so really depends on your child's caries risk. As mentioned in another comment, healthy dose of skepticism is always required. I usually try to show signs of decay either intraorally or detected on radiographs.