Why Placing Veneers over Crowns Is Inadvisable
In general, porcelain dental crowns last at least 7 years. In some cases, they last much longer. However, over time, crowns may leak and begin to appear dull and discoloured due to the presence of decay under the crown. Natural teeth also change colour over time due to staining which means the colour of the crown may no longer match that of the adjacent teeth. When this happens, dentists usually remove the crown and either clean it or completely replace it.
However, some patients who have become dissatisfied with the appearance of their crown may begin to explore the possibility of getting veneers. They wonder if it is possible to cover up their crown or crowns with veneers. While it is possible, it isn't advisable for several reasons.
A Replacement Dental Crown Looks Better
First of all, you should consider the appearance of such a combination. Although it is possible for a porcelain veneer or prepless veneer to be placed onto the surface of a crown, the crown will appear bulkier as a result.
Furthermore, porcelain-fused-to-metal crowns (PFM) do not blend well with veneers as the underlying metal will influence the appearance of a veneer when placed. However, when porcelain crowns and veneers are placed side by side, the result is often very pleasing to the eye and it can be difficult to tell them apart.
The Cost of the Two Treatments Is Similar
As the cost of a veneer is almost the same as that of a dental crown, the most logical, and aesthetical option would be to replace or simply clean the old crown. Also, remember that veneers are placed onto the surface of existing tooth structure whereas crowns are placed over a prepared tooth. This also means moving from one to the other isn't always possible, nor would many dentists suggest it.
A better option would be to replace the crown and have veneers placed on the adjacent teeth if that is what you wish.
The Procedure Is Complicated
For a veneer to be placed over a crown, the porcelain surface of the crown needs to be etched and primed much like the surface of a natural tooth would be. However, not only does this require the right—and expensive—equipment, but most dentists aren't trained to carry out this technique. No training is needed since it is standard procedure to replace old or failed crowns with new crowns—not cover them with veneers.
If you are not happy with the appearance of your crown or crowns, covering them up with veneers won't work, at least not in the way you intend. Speak to your dentist about replacing or cleaning crowns, teeth whitening and other services to leave you with a beautiful porcelain smile.