10% Teeth Whitening Kit - Gel Syringes Refills - Low Sensitivy (8 Units) - Fluoride, Carbamide Peroxide - Made in The USA by Ultradent 5211-4

I am a dental hygienist and absolutely love this product. I NEVER use a higher concentration than 10%. I use this gel in my custom trays and wear it overnight. I can get my enamel as white as piano keys. It's important to go "low and slow" to avoid sensitivity and this concentration fits the bill. It is also made of CARBAMIDE peroxide, rather than hydrogen peroxide, so it is better for avoiding sensitivity!

Edit/Edit - It took me almost a month of almost nightly whitening to get to my desired shade, so in total of 6 syringes of 10% carbamide. I'm too lazy to share before/after photos. I'll stick with buying this product for all maintenance whitenings going forward. I'm going to finish off the last two tubes to see how close to optic piano-key white I can get with 8 syringes. Edit: After an initial 5 nights of whitening my teeth were pretty white, but part of this was due to the teeth being dehydrated (and thus more sensitive). When you take a break for 1-2 days the teeth yellow a bit as the teeth rehydrate. So I started on another regimen, and am now on the 5th night of the second round, with 0.33 in 1 tube out of a total of 4 syringes used over 14 calendar days. Now I want to keep going to see if I can make my teeth look like piano keys. These work very well in your clear retainers. No need to purchase a separate custom whitening tray just for this. Check out the YT videos on how much to actually apply to each tooth-- it's just a small bead needed to the front of each tooth. I don't express a whole line of gel across the arch, this would be too much product. Also be aware that this is a perishable product. When I received the package, it had a remaining shelf life of 6 months. After, the gel loses efficacy. It doesn't drop to zero after this date, but just something to note. Amazon comped me an additional 8 syringes at no charge when I asked about the short shelf life. Start with buying 2 packs / 4 tubes of 10% Opalescence carbamide. I bought 4 packs / 8 tubes and there's no way I can get through all this stuff. I used only 1.75 tubes doing upper and lower arches for 6 nights and got to a very nice white shade, and any more my teeth would start to look like piano keys. I would've had to start from a much darker yellow shade in order to actually use up 4 tubes and go through two whole weeks of nightly whitening. And perhaps my teeth are more sensitive than others-- Definitely glad I started with 10% carbamide and not anything higher. By the 4th or 5th night I was starting to notice increased sensitivity, despite me having brushed with Sensodyne multiple times a day, every day for over a month prior. I also had braces removed a week ago, and experienced zero sensitivity during that procedure, for reference.

My dentist recommended I purchase these syringes of Opalessence whitener from Amazon, saying it was cheaper for me to buy from Amazon than from him. So, I did. There are ten syringes in a pack and are very easy to use. For an upper and lower "tray", I use just a tiny dot of whitener on each tooth in the trays, top and bottom, and I can just get three days out of one syringe. Need to be careful not to overuse the product in the trays or could cause sensitivity. But, I've been using these now for a few weeks and I'm happy with the whitening results. I'm getting ready to order some more syringes.

My teeth have always been dark & I drink coffee & red wine. Whitening at the dentist is very expensive. I use Opalescence 10%, leave it on for 3-4 hours, every month or so. My teeth are slightly sensitive for a few hours. After whitening, my teeth are a natural white, not neon white. I recommend this product.

Awesome whitening, no sensitivity. I have been using the 10% opalescence for years, and have had no sensitivity to my teeth or gums. Much better than other whitening products on the market.

I received a sample of this from my orthodontist after my braces came off. He gave me a syringe to use with my clear essix retainers. I noticed it making a difference so I decided to buy a few more. I have used the first set of 4 and I am pleased with my results so far! I notice a difference after each use. At first, I only used it for about 30 min. (via my ortho's advice) and slowly increased it to an hour, two hours, etc. This is to avoid any sensitivity to the product. I never had any major problems with it. I did notice a bit of sensitivity on my gums, but nothing that didn't go away after a short period of time. Now, I wear it overnight with no issues! It's decently priced here on Amazon and I much prefer the convenience of using my essix retainers and leaving it over night over the Crest whitening strips. I might even try the 15% next time instead of the 10% :)

These work even after using one vial. Easy to use.

I never knew that I had sensitive teeth until I tried to whiten them. My dentist said in order to decrease the discomfort, try using a lower percentage whitener and don't keep it on as long as it says to. If I kept it on too long I got a sharp pain in my teeth that felt like someone was stabbing me with an ice pick for hours...needless to say, that was no fun at all! I got very good results with this particular whitener and started off by using it for 30 minutes...even though it says you can use it for hours. I eventually was able to keep it on for an hour or more at a time with minimal discomfort. So my results are happening a little more slowly but it is well worth it to have whiter teeth without all the pain. I am already a couple of shades whiter and I'm looking forward to even whiter and nice looking teeth soon. I waited a long time to whiten my teeth....about 6-7 years. Once I get them the shade that I want them I'm going to use this gel once a year rather than waiting until they are more yellow than white. ;)