Black Triangles between new crowns - wait and see or replace crowns? (photos)

I recently had 4 new crowns places in my front teeth. They are emax crowns. They replaced old crowns that I had for 10 years. I have black triangles at the top of them and the floss glides between them very easily - unlike my other teeth - which makes me think they are too small for my mouth. Should I have them replaced? Will the black triangles eventually go away? It has been 1 full week since I had them placed.