D1- Dental benefit form

Hi, I will be getting a dental check up before Christmas and since I'm paying PRSI I've got a D1 dental benefit form.. do I send it off before I go to the dentist and then just give my PRSI number when I attend (the dentist participates in the scheme) or after I attend and claim the money back? Thanks in advance for any clarification!

I go to my dentist, he has the forms, I sign it there and pay whatever is not covered. I think you only get one free check up and scaling annually and some of the cost of certain dental work.

http://www.welfare.ie/EN/Publications/SW24/Pages/1WhatisTreatmentBenefit.aspx