Am I within my rights to ask for a copy of my dental X-ray?

I went to the dentist and had an X-ray on one of my teeth. I thought he was quite barbaric (the only way I can describe it) putting in the lining and also went straight to the prognosis that the either a root c or a deep filling as there is "decay" under a filling on that tooth. Either one is bad news but what I want to know is can I ask for my X-Ray and get a second opinion?