The two main products used to whiten teeth are hydrogen peroxide and carbamide peroxide. In contrast to a whitening toothpaste that uses an abrasive ingredient to mechanically remove stains at a surface level, the oxygen molecules in these whitening agents weaken the stains on your teeth at a molecular level.
Many over-the-counter (OTC) bleaches. strips, kit and pen 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 ability to isolate the teeth,” says Joseph Michael Brofsky, chief of pediatric dentistry at Cohen Children’s Medical Center in New York. “We use a special rubber barrier to protect the patient’s gums because if peroxide gets into the gums, it would burn them.”
Like home whitening products, there are a variety of professional teeth whitening methods. Professional in-office bleaching is a faster, if more expensive, way to brighten your pearly whites. Meanwhile, take-home custom trays fall somewhere between professional in-office whitening and an OTC bleach in terms of treatment time and cost.
Whitening in the office
Professional in-office whitening treatments are usually completed in several short appointments, but will depend on your unique needs. A bleaching agent is left on for 15- to 30-minute increments, and the entire appointment should take no more than an hour and a half.
There are a few types of in-office whitening treatments:
- A gel of high concentration of hydrogen peroxide, which is applied by syringe.
- A hydrogen peroxide combined with a high intensity light such as LED, UV or halogen. The light is applied by a lamp or laser device that sits just outside your mouth.
Halogen light and laser light increased tooth lightness more than hydrogen peroxide alone, according to a 2016 study in Journal of Conservative Dentistry. After three weeks, study participants in the halogen and laser light groups still had the white tooth color achieved during treatment, while the non-light group had “shade recovery” after just two weeks – the original bright teeth became darker.
However, some studies show no benefit from using a light tool such as a laser or light alone over a whitening gel.
Effectiveness aside, is exposure to light safe for your smile? 2020 study at 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 usually involves several steps:
- Your dentist will use a tooth shade chart to determine your current tooth shade. You will discuss how many shades lighter your smile can become after whitening.
- Your dentist will then use a pumice stone tool to polish your tooth and remove any remaining plaque.
- To ensure that the whitening agent does not touch any fleshy parts of your mouth, such as your gums, cheeks, or tongue, your dentist will use instruments to hold your mouth open. A dam 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 this is part of your treatment.
- If the particular whitening agent requires additional coatings, your dentist will reapply it.
- Once the whitening process is complete, your mouth is rinsed. Your dentist can apply fluoride, which will help alleviate any possible sensitivity.
- You and your dentist discuss whether your teeth have reached the desired shade and what lifestyle habits you should practice over the next day or so to allow the whitening agent to sink in. These include not eating brightly colored foods and resisting coffee and red wine. Immediately after whitening, your teeth become dehydrated, making them especially susceptible to liquid and food stains.
Even if you follow your dentist’s recommended regimen of resistance to bright foods, coffee, and wine, your teeth may look a little darker a few days after whitening. But don’t be discouraged. The dehydration caused by teeth whitening makes them look instantly shiny right after your procedure. After a week, if your teeth aren’t the shade you prefer, talk to your dentist about whether or not there’s a chance they can be lightened with at-home products or more office visits.
Discs for home
While in-office whitening is quick, custom take-home trays require some diligence on the part of the patient. It can be your only treatment or a follow-up treatment to in-office whitening if your dentist thinks your smile is prone to getting new stains again soon.
With a professional take-home tray, your dentist will take an impression of your teeth for a custom-made tray. Because this tray fits the shape of your mouth perfectly, it will usually give you more complete whitening results than OTC trays. Instead of a hydrogen peroxide-based gel, you’ll probably get a carbamide peroxide-based gel to put on the tray and use at home. Although 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 trays ranges from 10% to 38% carbamide peroxide, according to American Dental Association. The length of your treatment will also vary, from wearing your tray from two to 10 hours a day and up to 28 days. Over-the-counter discs come with a similar amount of carbamide. The quality difference is about the application. A custom tray will fit snugly around your teeth, giving minimal room for the gel to slide down to your gums or lose whitening in hard-to-reach crevices.
