Whitening: toothpaste, strips or pro?

Reviewed by Dr. Samar Fadavi, DDS

Short answer: Whitening toothpaste removes surface stains but barely changes the natural colour of your teeth. Over-the-counter strips use a mild bleaching gel and can lighten teeth gradually, with some sensitivity. Professional whitening, in the office or with custom take-home trays, gives more even, predictable results under a dentist’s supervision. Crowns, fillings and veneers do not whiten, so have a check-up first.

Why teeth change colour

Before choosing a whitening method, it helps to know what kind of discolouration you have, because each method works on a different kind.

• Surface stains sit on the outer enamel. Coffee, tea, red wine, cola, curry, berries and tobacco are common causes. These stains respond well to cleanings, polishing and whitening toothpaste. Our guide on coffee and your teeth explains how drinks stain.
• Deeper stains sit within the tooth. As we age, enamel thins and the yellower layer underneath, called dentin, shows through more. These changes need a bleaching gel that penetrates the enamel, such as strips or professional whitening.
• Stains from inside the tooth can come from an old injury, a root canal, certain medicines taken while teeth were forming, or too much fluoride in childhood. These often respond poorly to regular whitening and may need other options, such as internal whitening, bonding, veneers or crowns.

A single dark tooth is a special case. It can mean the nerve inside has been damaged, often after a knock years earlier. Have it checked before trying to whiten it.

This guide compares the three main whitening routes, what each can and cannot do, and how to protect your teeth along the way. It is general information for patients in Scarborough, the Danforth and East Toronto. For whitening at our clinic, see our teeth whitening page.

Option 1: Whitening toothpaste

How it works: most whitening toothpastes use mild abrasives and polishing agents to lift surface stains. Some contain small amounts of peroxide or other ingredients that help break down stains, but they are in contact with the teeth for only a minute or two, so they have little bleaching effect.

What to expect: teeth may look a little brighter as surface stains fade. The natural shade of the tooth does not change much.

Good for: people with mild surface staining who want to keep their teeth looking fresh between cleanings, or to maintain results after professional whitening.

Watch for: very abrasive pastes used with hard scrubbing can wear enamel and expose sensitive root surfaces over time. Use a soft brush and gentle pressure, and choose a toothpaste with fluoride.

Option 2: Over-the-counter whitening strips and gels

How they work: thin strips or paint-on gels contain a low concentration of peroxide. Worn on the teeth for a set time each day over one or more weeks, they bleach stains within the enamel.

What to expect: gradual lightening for many people with yellow-toned stains. Results vary widely.

Good for: adults with healthy teeth and gums, no visible fillings or crowns on the front teeth and mild to moderate yellowing.

Watch for:

• Sensitivity to cold during or after the treatment period, which usually fades when you stop.
• Gum irritation where gel touches the gums.
• Uneven results when teeth are crowded or rotated, because one-size strips do not reach every surface. The edges between teeth may stay darker.
• Overuse. Using products more often or for longer than directed increases sensitivity without improving results.
• Whitening over problems. Bleaching gel on a tooth with an open cavity, a cracked filling or exposed roots can be very uncomfortable.

Option 3: Professional whitening

Professional whitening starts with an exam to make sure your teeth and gums are healthy and to find any cavities, worn fillings or exposed roots that need attention first. Your dentist also records your starting shade so you can see the change.

Take-home trays: the clinic makes custom trays that fit your teeth closely. You place a whitening gel in the trays and wear them at home for the time your dentist recommends, usually over a couple of weeks. Because the trays fit closely, the gel stays on the teeth and away from the gums, which gives more even results and less irritation. The trays can be reused later for touch-ups.

In-office whitening: the gums are protected with a barrier, and a stronger whitening gel is applied to the teeth under supervision, usually in one visit. Results are visible the same day. Many people use take-home trays afterwards to maintain the shade.

Good for: people who want more noticeable, even results; people with crowded teeth; people who have had sensitivity with store products and want supervision; and anyone planning cosmetic work who wants to match new restorations to a lighter shade.

Watch for: sensitivity is still possible. Your dentist can adjust the strength, shorten wear times or recommend a desensitizing toothpaste or gel. Our guide on sensitive teeth explains more.

Comparing the three options

• Effect on natural shade: toothpaste, minimal; strips, mild to moderate; professional, moderate to marked.
• Evenness: toothpaste, surface only; strips, can be uneven on crowded teeth; professional trays, even because they are custom-fitted.
• Supervision: toothpaste and strips, none; professional, an exam first and follow-up.
• Sensitivity: toothpaste, rare unless very abrasive; strips, common but usually short-lived; professional, possible, managed by your dentist.
• Effect on fillings and crowns: none of them whiten fillings, crowns, bridges or veneers.

Fillings, crowns and veneers do not whiten

Bleaching gel works on natural enamel and dentin. Tooth-coloured fillings, crowns, bridges, veneers and dentures keep the colour they were made in. If you whiten teeth next to a front filling or crown, the restoration may look darker afterwards. For this reason, dentists usually suggest whitening first and then replacing visible fillings or crowns to match the new shade, if needed. Our guide tooth-coloured vs silver fillings explains filling materials.

If your concern is chips, gaps or the shape of your teeth rather than colour, bonding or veneers may be a better fit than whitening. See our guide to veneers and our cosmetic dentistry page.

Who should wait or avoid whitening

• People who are pregnant or breastfeeding are generally advised to postpone cosmetic whitening.
• Children and younger teens. The nerve inside young teeth is larger, which can increase sensitivity. Ask your dentist before whitening teen teeth.
• People with untreated cavities, gum disease or cracked teeth should have these treated first.
• People with very sensitive teeth or exposed roots should talk with a dentist before using any whitening product.
• People with allergies to peroxide or product ingredients.

Whitening trends to avoid

• Charcoal powders and pastes. They are abrasive, can wear enamel and may lodge in gaps and around fillings. Many do not contain fluoride.
• Lemon juice, vinegar or fruit scrubs. Acids soften and dissolve enamel, which can make teeth look more yellow over time.
• Baking soda scrubs used often and hard. Gentle occasional use in a toothpaste is fine; aggressive daily scrubbing can wear enamel.
• Unregulated gels sold online. Products of unknown strength or origin can burn gums and damage teeth.
• Whitening at a mall kiosk or salon without a dental exam. You may be whitening over a cavity or gum problem.

Protecting your results, step by step

1. Start with a check-up and cleaning. Removing tartar and surface stains often makes teeth look noticeably brighter on its own.
2. Choose a method that matches your stain type and goals.
3. Follow the directions for wear time and frequency. More is not better.
4. Use a fluoride toothpaste for sensitive teeth during and after whitening if your teeth feel sensitive.
5. Limit staining foods and drinks in the first days after whitening, when teeth pick up stains more easily.
6. Rinse with water after coffee, tea or red wine, or drink through a straw.
7. Do touch-ups as your dentist recommends rather than repeating full courses often.
8. Keep regular cleanings to remove new surface stains.

How long whitening lasts

Whitening is not permanent. How long results last depends on your habits. Coffee, tea, red wine and tobacco bring stains back sooner. Many people with professional results keep them for a long time with good home care and occasional touch-ups. Smokers usually see stains return faster.

Whitening and other dental work

Timing matters when whitening is part of a bigger plan.

• Before new fillings or crowns on front teeth. Whiten first, wait a couple of weeks for the shade to settle, then match the new restoration to the lighter shade.
• After braces or aligners. Many people whiten once orthodontic treatment ends, when brackets are gone and every surface can be reached. Our guide braces and other options explains alignment choices.
• After a cleaning. Whitening works more evenly on clean teeth. Book your cleaning first.
• Before a big event. Start several weeks early, so there is time for any sensitivity to settle and for touch-ups.
• After gum treatment. If you have had a deep cleaning, wait until your gums have healed and your dentist agrees.

Everyday habits that keep teeth brighter

Whatever whitening route you choose, daily habits decide how long the results last.

• Brush twice a day and clean between your teeth. Plaque picks up stains, so less plaque means fewer stains.
• Rinse after dark drinks. A quick swish of water after coffee, tea, cola or red wine helps.
• Use a straw for iced coffee and dark sodas to reduce contact with the front teeth.
• Wait about thirty minutes to brush after acidic drinks such as juice, pop or wine, so softened enamel can recover.
• Eat crunchy fruits and vegetables like apples, carrots and celery, which help clean tooth surfaces and stimulate saliva.
• Quit smoking or vaping. Tobacco is one of the most stubborn sources of staining, and quitting helps your gums too.
• Keep up with cleanings. Polishing at regular visits removes new surface stains before they build up.

Whitening for darker or single teeth

If one tooth has turned grey or dark, especially after a root canal or an old injury, regular whitening may not help, because the stain comes from inside. Your dentist may suggest internal whitening, where a whitening material is placed inside a root-canal-treated tooth for a short period, or a veneer or crown. An x-ray and exam come first, to check the health of the tooth and the root. Our guide what happens during a root canal? explains that treatment.

Some people also have white spots or streaks from early enamel changes or fluorosis. Whitening can make these spots less noticeable for some people and more noticeable for others. Your dentist can suggest options such as resin infiltration or bonding.

When to see a dentist

Book a visit before whitening if you have not had a check-up recently, if you have fillings or crowns on your front teeth, if one tooth is darker than the others, or if your teeth are already sensitive. Stop using any product and call the clinic if you have strong pain, gum burns or white patches on the gums. For whitening options at our clinic, see our teeth whitening page, and for more background, our guide to tooth whitening.

Questions about whitening

Does whitening toothpaste actually whiten teeth?

It removes surface stains, which can make teeth look brighter, but it does not change the natural colour of the tooth much.

Are whitening strips safe?

For most adults with healthy teeth and gums, used as directed, yes. Sensitivity and gum irritation are the most common side effects.

Why are my teeth sensitive after whitening?

The whitening gel can temporarily make the tooth more reactive to temperature. It usually fades within a few days after you stop.

Will whitening damage my enamel?

Used as directed, peroxide whitening does not wear away enamel. Abrasive pastes, charcoal and acids are the bigger risk to enamel.

Can I whiten if I have a crown on a front tooth?

Yes, but the crown will not change colour. Talk with your dentist about matching it afterwards.

Can I whiten my teeth while wearing clear aligners?

Sometimes. Ask your dentist, because some aligner plans include whitening and others suggest waiting until treatment ends.

Is whitening covered by insurance or the Canadian Dental Care Plan?

Whitening is cosmetic and is usually not covered by insurance. It is not covered by the Canadian Dental Care Plan.