A Bridge Too Dark: Dealing With Dental Bridge Discolouration Around The Gum Line

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Having a dental bridge fitted to replace one or more missing teeth can be a great boon, making your teeth more aesthetically pleasing and increasing your confidence. They can also make everyday oral activities, such as speaking and eating, easier. However, a dental bridge is not a foolproof solution, and even the most well cared for dental bridge can become discoloured and stained in a number of ways. 

Black lines or patches, which appear at the point where the base of your bridgework meets the gum line beneath, may appear at first glance to be the beginnings of tooth decay. However, there are a number of reasons these black marks can appear:

Metal bridge supports

While dental bridges made entirely of porcelain or resin are available, they are expensive and difficult to fit. As a result, dentists still routinely fit bridges with internal supports made of metal, ranging from non-precious alloys all the way up to gold. If a bridge is poorly fitted, has been damaged, or has shifted positions, this metalwork can be exposed around the base of the bridge. Receding gums can also cause the metal base of your bridge implant to become exposed.

Tackling this problem necessitates a visit to your dentist. In most cases, they will consult with a dental technician, who will manufacture small, porcelain 'margins'. These margins are then affixed to your bridges over the exposed metal to effectively hide the marks. If the metal has been exposed by receding gums, solving the problem can be more complicated -- an oral surgeon can graft gum tissue over the exposed metal, but you should also consult with your dentist on why your gums are receding and take appropriate measures to prevent further gum loss. 

Lack of UV exposure

Natural teeth are quite translucent and allow a certain amount of natural light to reach the gum tissue that holds them in place, causing it to turn the characteristic pink colour that generally denotes healthy gums. However, most bridges (particularly those with metal internal supports) are much more opaque, exposing the gums to much less sunlight and, in some cases. causing them to noticeably darken.

If your gums have darkened in this way, many dentists (particularly cosmetic dentists) will 'bleach' the darkened gum tissue until it matches the surrounding gums, using chemical treatments. This is not a permanent solution, however, so if you can afford the expense and potential time off work, you might want to consider having your bridges replaced with all-porcelain or resin bridges.

Leaking cement

Over time, the epoxy cement used to hold your bridge in place will break down and crumble. This degraded cement can leak out through the base of your bridge and stain the gums beneath. This is usually a sign that your bridge has reached the end of its service life, and you should schedule a consultation about replacing your bridge as soon as is convenient, before the bridge begins to degrade further.. 


Bruxism, more commonly known as teeth grinding, can damage bridges in the same way as it damages natural teeth. Damage caused to the gums by the pressure placed on the bridge during grinding can cause bleeding and blood clots that may appear dark brown or black. Alternatively, the marks may be visible because bruxism has worn away at the enamel crown of the bridge, causing it to become translucent and show underlying metal supports.

It goes without saying that a simple replacement job won't do here. Instead, you should seek advice from your dentist on how to combat bruxism before you schedule bridge repair or replacement, or your new bridge may well meet the same untimely fate. Bruxism has a wide range of potential causes, ranging from simple stress to more serious, underlying disorders such as sleep apnoea, so it is worth consulting a doctor too.

For more information about maintaining your dental bridge, contact a local dental clinic.