Why do porcelain veneers look yellow?
Ceramic itself is a material that rarely changes color, so when veneers look yellow or a dark line appears at the margin, it's often the surroundings that have changed rather than the porcelain. In the clinic we often hear, "The front teeth I had done years ago look yellow and there's a dark line near the gums." The cause is usually one of four.
- Surface staining: pigments from coffee, tea, smoking, and so on settle on the surface
- Cement or margin discoloration: old bonding cement takes on color or a gap forms
- Discoloration of the tooth underneath: a natural tooth or a tooth with root canal treatment darkens and shows through
- Gum recession: the gums recede and expose tooth surface the restoration didn't cover
Replacing the restoration based on the surface alone means putting new porcelain on while leaving the problem underneath as it is.
When do they need to be replaced?
We consider replacement when the ceramic chips or lifts, or when decay is suspected under the margin. If there is only surface staining and the ceramic is intact, we start with polishing and care.
| What you see | What to check | Next step |
|---|---|---|
| Surface staining only | Ceramic surface | Polishing and care |
| Dark margin | Cement, gums, decay | Remove the restoration and check underneath |
| Chipping or lifting | Fracture and bonding surface | Bond a new one |
| Recurring sensitivity or bleeding | Decay, inflammation, bite | Treat that first |
Some people come in after about 10 years of use when part of a veneer has chipped and come off. Even then, before replacing it, we first look at the remaining tooth and its underlying color. If the cause of the chipping is a habit of biting through hard things with the front teeth or tooth grinding, just making new porcelain means the same tooth will chip again.
Is the tooth prepared again when they are removed?
Not necessarily. However, decay, cracks, and the remaining tooth shape only become visible after the old ceramic and cement are removed, so depending on that condition, we refine only the parts that need it.
A second set of porcelain veneers is trickier because the bonding surface has changed. Enamel (the outer layer of the tooth) doesn't grow back once removed, and if dentin is widely exposed, the bonding conditions differ from the first time. Teeth that have been heavily prepared tend to show the yellow color of dentin through, so we also consider a design that masks a dark base. The process of removing and rebonding is summarized in the porcelain veneer rebonding article.
Won't it be noticeable if only one is replaced?
Just one can be replaced. However, it has to match the neighboring teeth not only in brightness but also in translucency and the texture of the edge, so it takes more work than doing several together. If the base is dark and the veneer is too translucent, gray shows through; if it's too opaque, it looks flatter than the neighboring teeth.
If you also want to brighten the neighboring teeth, we do teeth whitening first and match the new restoration's color after the shade has stabilized. That's because whitening works only on natural teeth and cannot change the color of ceramic.
How we do it at Wonjin Dental
I don't start by saying whether to replace; I first separate whether the discoloration is on the surface, at the margin, or underneath. If the cause of chipping is grinding or a strong bite, I don't just change the porcelain and leave the force as it is. I don't replace just the surface while leaving the cause underneath.
Before bonding a new one, I compare brightness and translucency with the neighboring teeth in the mouth and choose the cement color. If you grind your teeth, I plan a protective appliance, and if the toothbrush can't reach the margin, I plan a shape adjustment as well. Whether a method placed on top without preparation is possible can be seen on the Brinate page.
Frequently asked questions
Can whitening toothpaste remove staining on porcelain veneers?
Whitening toothpaste with strong abrasives can make tiny scratches on the ceramic surface, which can actually make stains stick more easily. Surface staining is safer to clean up with polishing at the dentist.
How often do porcelain veneers need to be replaced?
There is no set replacement interval. Rather than how long they've been in use, we decide based on chipping, lifting, decay at the margin, and gum condition.
Is a dark margin a cavity?
It may be cement discoloration, or it may be decay under the margin. It's hard to tell from the outside, so we check with X-rays and an explorer probe.
How long does replacing porcelain veneers take?
We decide after removing the old restoration and checking the tooth underneath. If there is decay or a gum problem underneath, that treatment comes first, so the day for bonding new ones may be pushed back.
