The two main products used for teeth whitening are hydrogen peroxide and carbamide peroxide. Unlike a whitening toothpaste that uses an abrasive ingredient to mechanically remove surface-level stains, the oxygen molecules within these whitening agents weaken your tooth stains on a molecular level.
Many over-the-counter (OTC) whitening strips, kits and pens also use a form of peroxide. The difference between these and professional teeth whitening is the chemical concentration.
“In the office, we use a very high percentage of hydrogen peroxide because we have the capability to isolate the teeth,” says Joseph Michael Brofsky, head of pediatric dentistry at Cohen Children’s Medical Center of New York. “We use a special rubber dam to protect the patient’s gums because if peroxide gets onto the gums, it would burn them.”
Like at-home whitening products, there are a variety of professional teeth whitening methods. In-office professional whitening is a quicker, albeit more costly way to lighten up your pearly whites. Meanwhile, custom take-home trays fall somewhere between in-office professional whitening and an OTC whitener in terms of treatment time and cost.
In-office professional whitening treatments are typically completed in several short appointments but will depend on your unique needs. A whitening agent is left on for 15- to 30-minute increments, and the entire appointment should take no longer than an hour and a half.
There are a few types of in-office whitening treatments:
- A high concentration hydrogen peroxide gel, which is applied by a syringe.
- A hydrogen peroxide combined with a high-intensity light, like LED, UV or halogen. The light is applied by a lamp or laser device that sits directly outside of your mouth.
Halogen light and laser light increased teeth lightness more than hydrogen peroxide alone, according to a 2016 study in the Journal of Conservative Dentistry. After three weeks, study participants in the halogen and laser light groups still had the white teeth color achieved during treatment while the non-light group had “shade rebound” after just two weeks—initially brightened teeth became darker.
However, some studies show no benefit from using a light tool such as a laser or lamp over a whitening gel alone.
Aside from effectiveness, is light exposure safe for your smile? A 2020 study in Materials found that tooth cells recovered well after LED light-accelerated technology, concluding that most side effects are “temporary and transient.”
What to Expect at an In-Office Teeth Whitening Appointment
In-office whitening typically involves several steps:
- Your dentist will use a tooth shade chart to determine the current shade of your teeth. You’ll discuss how many shades lighter your smile may become after whitening.
- Your dentist will then use a pumice tool to polish your tooth and remove any remaining plaque.
- To ensure the whitening agent doesn’t touch any fleshy parts of your mouth like your gums, cheeks or tongue, your dentist will use tools to keep your mouth open. A barrier is placed along the gum line.
- Your dentist then applies the whitening agent and leaves it on for up to an hour. This is also when your dentist would use light activation if that’s part of your treatment.
- If the specific whitening agent requires additional coats, your dentist will reapply it.
- Once the whitening process is complete, your mouth is rinsed. Your dentist may apply fluoride, which will help mitigate any potential sensitivity.
- You and your dentist discuss if your teeth have reached the desired shade and the lifestyle habits you’ll need to practice for the next day or so to let the whitening agent sink in. These include not eating brightly colored foods and resisting coffee and red wine. Immediately after whitening, your teeth are dehydrated, making them extra susceptible to liquid and food stains.
Even if you stick to your dentist’s recommended regimen of resisting bright foods, coffee and wine, your teeth may appear a bit darker a few days after whitening. But don’t be discouraged. The dehydration caused by teeth-whitening makes them look immediately bright right after your procedure. After a week, if your teeth are not at your preferred shade, speak with your dentist about whether or not there’s potential for them to become lighter with at-home products or more in-office visits.
While in-office whitening is fast, custom take-home trays require some diligence on the part of the patient. They may be your only treatment or a follow-up treatment to in-office whitening if your dentist believes your smile is prone to getting new stains again soon.
With a professional take-home-tray, your dentist will make an impression of your teeth for a custom-fabricated tray. Because this tray will fit perfectly to the shape of your mouth, it will typically give you more comprehensive whitening results than OTC trays. Instead of a hydrogen peroxide-based gel, you’ll most likely get a carbamide peroxide-based gel to place in the tray and use at home. Even though it doesn’t whiten as quickly as a hydrogen peroxide-based gel, you’re less likely to experience sensitivity if you accidentally get it on your gums, cheek or tongue.
The concentration of the gel your dentist gives you for your custom-fit trays ranges from 10% to 38% carbamide peroxide, according to the American Dental Association. Your duration of treatment will also vary, from wearing your tray from two to 10 hours a day, and for up to 28 days. Over-the-counter trays come with a similar percentage of carbamide. The difference in quality is in regards to fit. A custom tray will fit directly around your teeth, giving little room for the gel to slip up to your gums or miss whitening hard-to-reach crevices.