Before anything else, here’s advice that costs you nothing: if you think your problem is ordinary surface stain, try drugstore whitening strips first.
We mean it. Peroxide is peroxide, and the active ingredient in a pharmacy strip does the same chemistry as the gel we’d give you. What’s different is the strength, how long it stays on the tooth, and how well it’s held there. For a lot of people, strips are enough, and we’d rather you found that out for twenty dollars than for several hundred.
This page is for the people strips don’t work for, and why they don’t.
First: is it stain at all?
This question decides everything, and it’s the one people skip most.
Bleaching removes stain. It does nothing at all for a tooth that looks yellow for a structural reason, and there are several of those.
- Thinning enamel. Enamel is partly see-through, and the dentin underneath is yellow. As enamel wears or erodes, more of that yellow shows. The tooth isn’t stained, it’s thinner, and no amount of peroxide will change the color of dentin you can now see. Wear has its own article, because the color is usually the least of it.
- A single dark tooth. Usually a nerve that died, often years after a bump nobody remembers. That’s a problem inside the tooth, and whitening from the outside won’t reach it.
- Staining inside the tooth from medication or fluorosis. Tetracycline bands and fluorosis spots are inside the tooth, not on it.
- Old dental work. Fillings, bonding, crowns and veneers don’t whiten at all. Whiten around them and they stay exactly the same color, which can be an unpleasant surprise.
The most useful clue is your own history. If whitening did very little last time, or left your teeth looking grayer instead of whiter, that points to thinning enamel, not stain. That’s good to know, and it changes the conversation from whitening to what would actually improve how your teeth look.
Figuring out which of these you have takes an exam and a photo, which is why we won’t sell you a whitening kit over the phone.
What we use when strips aren’t enough
We use KöR® Whitening. In practice we almost always use the KöR ULTRA level instead of starting people on the lighter kits. For the kind of discoloration that brings someone to us after drugstore whitening has already failed, starting lower usually just wastes a round.
What makes the system different isn’t a stronger gel. It’s how long the gel keeps working.
- The trays are made to seal. They’re designed to keep saliva out, because saliva breaks down peroxide. A tray that leaks stops working early.
- The gel stays refrigerated from the factory to our office. Peroxide breaks down sitting on a shelf, and keeping it cold is the unglamorous reason the product works the way it does.
- You wear it overnight, not in a dental chair. That’s where the extra time comes from.
KöR says each application whitens actively for about 6 to 10 hours, compared with roughly 20 to 30 minutes for a regular tray. That comparison is credited to Clinical Research Associates and to Dr. Rod Kurthy, who developed the system, so it isn’t an independent source. We quote it because the mechanism makes sense and our results are consistent, not because the number was independently tested.
Why we don’t offer a one-visit whitening appointment
You’ve seen them advertised everywhere: one visit, a light, dramatic before-and-after photos. We don’t sell one, and here’s why.
KöR’s own position is that no in-office-only system gives predictable, long-lasting results. That’s the manufacturer saying it about its own kind of product. A single session can make for a striking photo, mostly because the teeth dry out and look whiter for a few days. The color you’re left with a month later is a different shade from the one on the chart at the end of the appointment.
An in-office session makes sense as a boost at the start of a take-home course, not as the whole treatment. Anyone selling you the appointment on its own is really selling you the photo.
Sensitivity, and what helps
Sensitivity during whitening is common and usually temporary, and it’s the main reason people quit halfway through.
What helps: don’t double up when you’ve missed a night, use a desensitizing toothpaste in the weeks before you start instead of scrambling for one afterward, and tell us early instead of pushing through. Bad sensitivity is a reason to slow the schedule down, not to stop, and it’s easier to handle before it becomes the thing you associate with the trays.
Sensitivity that was already there before any whitening is a different conversation, and often a more useful one. It’s often exposed root surface or worn enamel, which means whitening was never the answer.
Whiten before new dental work, never after
If there’s any chance of bonding, veneers or a crown on your front teeth, whitening comes first.
Porcelain and composite don’t whiten. Whatever shade your natural teeth are on the day the work is made is the shade it’s matched to, for good. Whiten afterward and your own teeth get lighter while the new work stays the same, which is how a front tooth ends up not matching the one next to it.
Whiten, give the shade a couple of weeks to settle, then match to it. We walk through the whole sequence on the cosmetic dentistry page.
How long it lasts
Teeth don’t stay where whitening leaves them, because whatever stained them is still part of your life. Coffee, tea, red wine and tobacco all keep at it.
What makes a take-home system worth the money is that you keep the trays. A night or two of touch-up once or twice a year holds the result with a fraction of the original effort. That upkeep is the difference between whitening once and having white teeth.
One timing tip: don’t brush right after anything acidic, and that includes wine. Enamel stays softer for a while afterward. Rinse with water and wait. Our article on acid explains why that matters even more than the staining.
The longer version
We’ve written all of this up in more detail, including how to tell stain from thinning enamel yourself, what drugstore products can and can’t do, and what happens with a single dark tooth: Why Won’t My Teeth Get White? →
Where to start
If strips haven’t worked for you, if one tooth has gone dark, or if you want to know whether what you’re seeing is stain at all, that’s a job for an exam and a photo, not a sales pitch. Call 702-734-0776.