What Causes The Discoloration Of A Ceramic Dental Crown?
Anyone in need of a dental crown has three general options — acrylic (plastic), ceramic, or precious metal (typically a gold alloy). Acrylic crowns are the most cost-effective but will degrade and discolor more quickly than the other materials on offer. Precious metal crowns are very durable but can be noticeable. They're usually reserved for rear teeth (molars and premolars) where their strength comes in handy. This is why most patients opt for ceramic crowns. They're strong and resemble natural dental enamel. However, as the years go by, you might begin to notice that your ceramic crowns don't look as natural or pristine as they once did.
Ceramic crowns aren't noted for their tendency to discolor, but this isn't to suggest that it can't happen. Much like your dental enamel, the color of your crowns can be affected by external elements (your diet, and whether you're a smoker). The gradual discoloration will occur, leading to the crown taking on a yellow hue. Don't attempt to whiten your ceramic crown. The chemical reaction created by whitening gel will have little effect on ceramic, and may even have a corrosive effect, making the crown brittle and more prone to breakage.
Decay Beneath the Crown
You should also consider the fact that the discoloration may not be the crown itself. A ceramic crown is very thin and is partially translucent (allowing it to mimic dental enamel). If the underlying tooth has begun to decay, the discoloration may be related to this issue, which is visible through the wafer-thin ceramic.
Your Other Teeth
It can also be that the crown has retained its color, and it's in fact your natural teeth that have yellowed. This makes the color mismatch of the crown far more evident, even though the crown hasn't deteriorated in any significant way.
Correcting the Discoloration
Since there are different possible causes for the apparent discoloration of a ceramic crown, there are different solutions. If your natural teeth have yellowed, your dentist can whiten them so that they match your dental restoration. When the tooth beneath the crown has decayed, your crown will be removed so that the decay can be removed (the tooth may need a filling). The crown can then generally just be re-cemented back onto the treated tooth. Should the crown itself be stained, your dentist can often polish it to restore it to its former color. In some cases, it's more practical to simply replace the crown.
A discolored ceramic crown isn't a major problem. But since it can sometimes indicate a serious problem with the underlying tooth, it's always in your best interests to see your dentist, so any necessary corrective work can be performed. Fortunately, in most cases, a discolored ceramic crown is nothing more than a cosmetic (and easily corrected) concern.