Black line showing, all porcelain bridge

Porcelain bridge, or porcelain crowns can not 100% block out a dark black color tooth, unless more thickness is added, meaning the bridge will be bulkier. porcelain crowns or porcelain bridges at best can block out 90% of color, but not 100%.If you want a 100% block out of color with porcelain restoration, the dentist must use porcelain fused to metal or porcelain fused to gold, or internally bleach the abutment tooth prior to taking final impression.

Hi:If the tooth is root canaled, it will eventually discolor toward black shade.  No matter how many times the crown or the bridge is replaced as soon as there is any gum recession the black line reappears.  Best,Dr. Maddahi

Hi, thanks for your question, and I'm sorry to hear that your bridge has a dark line showing. It is my opinion that it is entirely possible to hide a black line at the gumline around a bridge. Using a bridge with a zirconia (ceramic) substructure, and porcelain over it, or a fully zirconia bridge (all ceramic), along with an opaquing cement, it is entirely possible to hide the darkness from a tooth underneath. One important key, almost more important than the bridge material, is that the preparation margin (called the finishing line) must be slightly subgingival (under the gum line). If you do not put the margin under the gum line, and there is any type of movement of the gum after you cement that bridge (there usually will be a movement of .1-.5mm) then the dark tooth root will show. I hope this gives you a better understanding of why you may be showing that darkness at the gum line. 

You should not have this result. Your dentist should have prepared the abutment teeth below the gum line. If the bridge is in fact below the gum line and black is showing, the incorrect material was used, allowing light to shine through and show your discolored abutment tooth. Depending on how your dentist operates, you may get him to switch it out for free or a discount if you want to go through with it. If you do, ask him about full contour zirconia bridges or porcelain fused to zirconia bridges (depending on where the bridge is in your mouth). Teeth cannot be seen through these materials. 

HI, thanks for sending your question. If you had an all porcelain bridge placed then the black discoloration that you are seeing could typically be from your own tooth which is discolored. Often root canal teeth can discolor greatly turning dark, which in turn can cast a shadow at the margin giving a transparency of the dark tooth underneath. If this is recent dentistry that has been performed often the gum tissue can recede which can also show the discoloration of the actual tooth underneath; you can help this situation by massaging your gums towards the chewing surface of your tooth to help with the recession.  If you are concerned more about this consult with your dentist to make sure your needs are addressed.   All the best.

How are your gums?  When was the bridge replaced?  How long was it before you noticed the line again? If the gums aren't happy, even if the bridge went to the gums when first inserted they will recede again.  Are you using a soft toothbrush?  Good luck!