Just been to dentist and had two fillings on lower teeth, seemed to go ok, although I have a small mouth which makes work difficult, but then looked in mirror at home and could see two hair line cracks down the centre of my two front teeth (upper). Seems to be an obvious line, and not an undulation on the exterior, it is a line within the tooth, never seen this before. Is this a common flaw in front teeth or could the dentist have done this?
Go back anyway as thy may need some reinforcing work I had a tooth crack like that eventually it needed replacing with a crown but I think they have ways of sealing them now to reduce the risk of decay
on googling they appear to be also called craze lines and are very common and don't need work doing to them unless you find the line distressing and you can cosmetically replace or cover the tooth.