Why are my gums dark/red after crowns with other discoloration? (photo)

Based on your photos and your description, it sounds like you are having some bacteria accumulation around your gum margins.  This is most often due to poor oral hygiene or a non dental friendly diet.  I would suggest getting regular teeth cleaning by a dental hygienist every 6 months, then following better home care and your crowns should last another 20 years without incident.  Good luck and I hope this helps. Follow me if you have more questions.Sarah Thompson, DMD

From looking at your pictures and reading what you wrote, you possibly have marginal tissue inflammation around the crowns.  Most dentists would easily recognize this upon examination.  This inflammation occurs due to plaque buildup at the margins of crowns, whether natural or artificial.  If around artificial crowns it can be do to poor home care even when the crowns are properly done or it can be due to poor crown margins despite your best efforts a keeping them clean.