Best Acrylic Prosthesis doctors in Ardee City

I have a question about my teeth. I found a small, stone or teeth like structure on the left side of my teeth at the end without any pain, redness, or swelling. There's also a black line on one tooth that doesn't appear to be a cavity and doesn't hurt or is sensitive. Can you help me understand these issues, I have attached the pictures.

Female | 18

What is the Cost of root canal?

Female | 44

How long does a typical tooth whitening session take?

Female | 38

Hi my father has a severe problem of aphthous ulcer. It first happened in 2016. The condition was so bad that we had to admit him to the hospital. After that he was fine. But in last 6 months it repeated two times. We were aware of the condition so he got the treatment early. But my question is why it is happening again and again? We visited a doctor at Bayrampasa but were not satisfied. Can you suggest a good doctor in Istanbul who handles this type of patient earlier?