Question about dentist and medicaid

I recently when to the dentists covered by Medicaid annual cleaning and check up. The dentist didn't do an X-ray to check for any cavities and only asked if I had any discomfort and I did point out one cavity I saw one of my tooths. He only took an X-ray of the area that I pointed out only and filled it. About two months later I see another cavity that I misses, it's black and it's on one of my molars.

My question is will I be able to get the filling/cavity covered by Medicaid even though I went to my annual cleaning already? Is it normal/common practice that my dentist didn't x-ray/check for any other cavities?