The NHS policy is now to encourage practices to employ therapists to do routine fillings , children's fillings, baby teeth extractions etc leaving dentists to do the more complicated treatment. It's all about trying to keep the NHS limping along without any more investment.
Some private practices use therapists in a similar way . Therapists are trained to do injections, fillings, baby teeth extractions, impressions , x rays and in NHS practice simple check ups . Anything else can only be done by a dentist.