A dental therapist has the same role as the dental hygienist but in addition can do fillings and remove baby teeth in children and some fillings in adult teeth.
Any treatment carried out by a hygienist or therapist has to be prescribed by a dentist. This means that the dentist will have diagnosed the dental/gum problem, identified the treatment required and instructed the hygienist or therapist of what is required. The dentist always maintains the lead role especially in treating gum disease.