http://www.nhs.uk/NHSEngland/AboutNHSservices/dentists/Pages...
>You will not be charged for individual items within a course of treatment. Depending on what you need to have done, you should only ever be asked to pay one charge for each complete course of treatment, even if you need to visit your dentist more than once to finish it. A course of treatment is finished when your dentist considers good oral health has been achieved.
Have I misunderstood what you meant?