
Yellow teeth look disgusting – I think we can all agree on that.
Which is why teeth whitening has quickly grown into a multi-billion-dollar industry. No one wants their teeth looking like kernels of corn.
By using teeth whitening trays or strips, you can quickly take your smile from dull to dazzling.
But if you’ve ever whitened your teeth, you know that while you’re whitening, there’s not much else that you can do.
You can’t eat, talk, drink, etc.
But…can you sleep?
Theoretically, it seems like the perfect time to lay back and let those whitening strips or trays polish up your smile while you snooze away.
But it’s a bit more complicated than that. In general, sleeping with whitening strips is a bad idea. But sleeping with certain whitening trays can be acceptable – if you do it right.
Really, there’s no one-size-fits-all answer when it comes to whitening your teeth in your sleep.
Let me explain…
Sleeping with whitening strips

You should not sleep with whitening strips on your teeth.
It plainly says so on the Crest website1 – and they’re the largest and most popular supplier of whitening strips. Which kind of makes them experts. But most dentists agree with them.
The reasoning is pretty simple.
There are four potential outcomes from sleeping with whitening strips over night. And none of them are good.
1. Extra Sensitive Teeth
The bleaching solution in whitening strips is highly concentrated. This is because you’re only supposed to wear them for a finite amount of time. When left on for too long – like overnight -the whitening bleach will wear down tooth enamel which can damage teeth.
My dentist once told me teeth are like M&M’s – hard outer shell, soft inner core.
Whitening solutions wear down that outer shell, your enamel, and seep inside of your teeth, where you have lots of nerves.
When you wear a whitening strip for too long, like when sleeping, it will significantly wear down enamel and reach the nerves inside of your teeth.2
OUCH!
If this happens, it can cause extreme tooth sensitivity; which feels like you aretrying to sleep with a toothache.
2. Gum Irritation
Whitening strips work by sticking to your teeth and depositing a certain amount of bleaching gel on the surface.
Problem is, the strips are pretty much one-size-fits-all. And not all teeth are the same size.
I have very tiny teeth; my sister has much larger teeth. If we’re both wearing the same type of whitening strip, it’s going to fit us differently.
The strip may never touch her gums thanks to her nice, full-sized teeth. But with my little chicklet teeth, the strip will likely end up covering part of my gums.
Even if the strip never touches your gums, when you sleep in a strip, the saliva moving around your mouth causes the gel to spread. This means some of it will probably end up seeping onto your gums.
Bleaching gel soaking onto your gums overnight is NOT comfortable. If you sleep with a whitening strip on, you can count on waking up with sore, irritated, inflamed gums.3
3. Sore Throat
When you sleep with whitening strips on, you’re going to swallow some of that bleaching gel. There’s no way around it.
Even though you don’t generally swallow while asleep, saliva still pools up in your mouth. Those of you who drool in your sleep will be well aware of just how much saliva can build up overnight.
With strips on your teeth overnight, the whitening gel will mix in with your saliva and some will drip down your throat throughout the night.
Ingesting such small amounts of whitening formulas is generally not dangerous – but it can cause you to wake up with a sore, scratchy throat.4
The constant drop of bleaching formula down your throat while you sleep will irritate your throat.
4. Swallow or Choke on Strips
Wearing whitening strips for too long wears down the whitening formula and which keeps the strips stuck to your teeth. Which doesn’t exactly make them suitable for wearing in your sleep.
Once the adhesive quality of the gel is gone, the strips can come loose and fall off your teeth, causing you to swallow or choke on it.
Can you imagine waking up with a chunk of plastic lodged in your throat? Or worse, not waking up at all thanks to choking in your sleep?
This may not be a highly likely situation, but it is possible.5 And I want whiter teeth as much as the next person, but I’m certainly not willing to risk my life for them!
To stay safe and ensure that you wake up in the morning – don’t sleep with whitening strips on!
And on top of all that, there is no added benefit for sleeping in whitening strips
So even if none of these negative outcomes happen, there still isn’t a good reason to sleep with whitening strips on your teeth. I mean, it’s not going to make your teeth any whiter.
Each strip comes coated with a limited amount of solution or gel. After a certain amount of time, the whitening agent in the gel is used up and broken down.
Once all that whitening agent is used up, what’s the point in leaving them on?
The other ingredients in the gel will only continue to irritate your teeth and gums without any added whitening. And if sleeping with whitening strips on won’t give you whiter teeth – what’s the point??
Not only is there no real benefit to wearing whitening strips overnight, but it can be really harmful to your teeth and gums. Not to mention, the whole choking thing.
The bottom line is if you are going to use whitening strips on your teeth, do it during the day, and not while you sleep.
Sleeping with whitening trays

Unlike whitening strips, it is possible to wear whitening trays safely and effectively overnight.6
Deciding if sleeping in whitening trays is a good idea for you personally really depends on a few things.
1. Strength & Type of Whitening Gel
When it comes to at home whitening trays with gel, there are a few different formulas. The most common are Carbamide Peroxide gels and Hydrogen Peroxide gels.
The lower strength Carbamide Peroxide gels – 10%, 15%, 16% – are generally safe to leave on overnight or for longer periods of time.7
Higher concentrations, like 20% or above, should only be worn for 1 hour. And given that most people sleep for 8 hours, this makes high-strength whitening gels unsuitable for snoozing in.
And even so, most dentists advise against wearing Hydrogen Peroxide bleaching gels overnight entirely. It’s suggested to only leave these gels on your teeth for 30 minutes to 1 hour.
When purchasing gel for your whitening trays, it’s always a good idea to either speak with your dentist or follow the directions when purchasing OTC or online. This will help you decide if overnight wear is a good idea.
2. Tooth Sensitivity Before and During
Any dentist will tell you that if you’re experiencing extreme tooth sensitivity, wear your trays for less time.
Everyone’s teeth are different. If the gel you choose for your trays is safe to wear overnight and you only experience mild sensitivity – whiten while you sleep!
But if you experience extremely sensitive or painful teeth when whitening while you sleep -even if the gel is safe for overnight use – stop!
Most people will experience some level of tooth sensitivity immediately after whitening – this is normal. It really comes down to personal pain tolerance and tooth sensitivity when debating overnight whitening.
3. Level of Whitening Desired
Are your teeth so yellow that it looks like you bit into a stick of butter? If so, you may be a candidate for overnight whitening.8
The darker or more stained your teeth are, the longer it will take to lighten and whiten them. If the gel you’re using is safe for longer wear, then sleeping with your whitening trays might help speed up the process.
What you don’t want to do is try to rush it. I get it, yellow teeth are gross and you want a quick fix.
But using a too-highly concentrated gel while you sleep can seriously damage your teeth.
When you take teeth whitening to the extreme, it can end up backfiring. Connie White DDS, a spokesperson for the Academy of General Dentistry, says the following in regards to whitening teeth for too long…
Instead of looking beautiful, they get a chalky look or white splotches and look really bad.
Not everyone looks good with glow-in-the-dark white teeth – remember the episode of Friends where Ross over-whitened? Creepy.
If you only want to whiten a few shades, there’s no reason for you to sleep with your trays in. Mild whitening can be easily accomplished with several hours of continued daytime wear.
Custom Trays or One-Size-Fits-All
When talking about whitening trays, there are two options:
- Take a trip to the dentist and pay about $500 to have custom-fit whitening trays made
- Buy an OTC version that offer one-size-fits-all trays
If you want to sleep in your whitening trays, your best bet is to suck it up and spend the money for custom-fitted trays. Connie White DDS says,
If you go for an option that’s not custom-sized, you can actually get chemical burns on your gums.
OTC trays are often uncomfortable and ill-fitting. Since they’re not custom fit to your teeth, gel can ooze out and get all over your gums or drip down your throat. Not to mention they are not exactly comfortable, which can keep you awake at night.
For short spurts of whitening, store-bought trays are fine. They’re just about as effective as the whitening strips.
But for long hours of overnight wear, it’s better to invest in properly fitting whitening trays. These ensure that the gel stays where you want it – on your teeth!
Whitening your teeth while you sleep is a great way to go – if you do it right. Always consult your dentist first before sleeping with teeth whitening products.Do you sleep with whitening trays or strips on? Let me know in the comments below!
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