Your two upper central teeth are meant to be more dominant than the rest of your teeth. If you have a look a my portfolio- www.umbrellasmiles.com you will see examples of this. It allows the teeth to follow the curve of your lip giving a beautiful smile.
If you really dislike this then you may be able to have them recontoured slightly. This would not be a painful procedure but once you have the length taken away, you cannot have it back so make sure it is something you are sure about before commencing with any treatment.

Kind regards
Dr Justin Glaister