Isn't this the case with other healthcare providers too, and not necessarily just dentists? For example, physicians will regularly make you wait at least 15 minutes—even in an empty office—so they can bill insurance for that extra time. They'll bill patients for "emotional/grief counseling" and lots of other unrelated charge codes as well. I've seen from firsthand experience how doctors will exploit patients and try to milk as much money as they can from them, rather than prioritizing their wellbeing and health.