My one implant front tooth is too white. How can I darken it?

The only way to have made it darker is to custom stain it chair side, usually done by a lab technician based on the shades the adjacent teeth have.

Hi:The most cost effective option is to whiten the rest of the teeth, if the crown is too light you will have to replace the crown.Best,Dr. Maddahi

The only way to change the color of a crown is to replace the crown. Once a crown has been cemented the color can't be adjusted.

Two choices:1. Replace crown with new one that is proper shade2.  Use veneers or bleaching to lighten surrounding teeth to match.I am in Chicago but when doing a single front crown, especially on an implant the best approach is to have custom staining of ceramic done in office.  My lab man and his wife who has an excellent color eye  works with me and my patients to acieve highly esthetic crowns that mimic shade, staing, surface area, reflective light patterns.  This is art but many dentists never offer these high end services