Professional teeth whitening uses a peroxide gel to lighten the colour of natural tooth structure. It is not a cleaning and it is not a coating. It changes the teeth you were born with and nothing else in your mouth.
You can have teeth whitening assessed and planned at our Britannia Road West office in Mississauga. The exam comes first, because whitening an unhealthy mouth treats the wrong problem.
What whitening can and cannot change
This section decides whether you will be happy with the result, so it comes first.
| Whitening changes it | Whitening does not change it | |
|---|---|---|
| Natural enamel and dentine | Yes | |
| Surface stain from coffee, tea, wine, tobacco | Yes, and a cleaning removes much of this too | |
| Crowns, veneers, bridges, fillings | No. They stay exactly the colour they are | |
| The shape or position of a tooth | No | |
| A single dark tooth after injury or root treatment | Not reliably by whitening from outside alone | |
| Decay, gum disease or a cracked tooth | No. These need treating |
The two ways professional teeth whitening is done
In-office whitening puts a strong gel on your teeth with the gums isolated and the dental team stays with you throughout. Published trial protocols run it as two or three sessions about a week apart instead of one long appointment.
Take-home whitening uses a weaker gel in trays made from an impression of your teeth. You wear them for a set time each day across one to two weeks. A Cochrane review of home-based whitening found it does lighten teeth, with tooth sensitivity and gum irritation as the common side effects.
The trays are the part that matters. Custom trays hold gel against the tooth and keep it off the gum. One bought off a shelf does neither and that is the difference you are paying for. Fit is the whole product.
Which route suits you depends on your starting shade, your sensitivity and how quickly you want the change. Ask at the consultation. The answer is different for a smoker with even staining than it is for one dark front tooth.
Does laser or light activation help?
The published evidence says no.
A 2026 umbrella review in the Journal of Esthetic and Restorative Dentistry pooled ten systematic reviews published between 2007 and 2024 and found that laser and light activation showed no consistent improvement in the final whitening result when it was measured against the same gel used without a lamp over the top of it. Sensitivity was not reduced and some high-energy protocols made it worse.
Separate work in 2026 measured enamel surface hardness after three in-office protocols. The light-activated one produced the biggest immediate drop and recovered the least over the following four weeks.
One light finding did hold up. Photobiomodulation, a low-level light used after bleaching and not to drive it, reduced post-bleaching sensitivity in placebo-controlled trials without weakening the colour change. That is a different thing from a lamp sold as a way to speed the gel up.
If a teeth whitening page offers laser or light activation as the upgrade, ask what it is buying you before you pay for it.
What teeth whitening costs in Mississauga
We quote after the exam and you get a written estimate before treatment begins. The ranges below are what whitening costs across this area. They were collected from published prices in September 2026.
| What you are buying | Price range | Who does it |
|---|---|---|
| In-office whitening at a dental office | $400 to $1,000 | Dental team, gums isolated, exam first |
| Professional take-home kit with custom trays | $250 to $600 | Trays made at the office, you whiten at home |
| Whitening bar or beauty salon session | $80 to $260 | Not a dental office |
| Over-the-counter tray kits | Under $100 | You, with no exam |
| Over-the-counter strips and gels | $20 to $40 | You, with no exam |
Whitening is cosmetic treatment and the Canadian Dental Care Plan does not cover it. The plan is open to all ages for eligible Canadian residents; eligibility requires no access to private dental insurance, the required Canadian tax returns, adjusted family net income under $90,000, and Canadian residency for tax purposes, and it pays for treatment you need, not treatment you want. Private plans set their own rules for cosmetic work, so confirm with your insurer before you plan around it. We offer direct insurance billing for treatment your plan does cover.
If something has to be sorted out before you whiten, such as a cleaning or a filling, ask whether that is in the quote.
Read about dental coverage and CDCP.
Whitening bars, salons and the price gap
The gap between $80 and $400 is real. What you buy at the higher price is an examination that rules out decay, a leaking filling, gum disease and a cracked tooth before any gel goes near your teeth, plus gum protection made to fit your mouth and a dentist who answers to a regulator.
Whitening at a beauty bar is a cosmetic service. Nobody there examines your teeth for decay, a leaking filling, gum disease or a crack. None of those improve as you whiten over them. A dark tooth with a dying nerve is the clearest case, because the session changes how it looks and delays finding out what is wrong.
Ask any non-dental provider what is in the gel and how your gums are protected. Then ask who you call if something hurts two days later.
Not all staining responds the same way
Surface staining from coffee, tea, red wine and tobacco is the kind that lifts most. Dentists call it extrinsic. A professional cleaning removes a good deal of it on its own, which is why it is worth doing first.
Staining from inside the tooth is intrinsic. Discolouration from an injury, a nerve that died, certain medications taken as the teeth were forming, or plain age responds less predictably. Some of it does not respond at all.
One dark tooth is a different problem. A single tooth that has darkened, especially a front tooth, can be a sign of trouble with the nerve inside it. It needs examining before any whitening. Whitening it from outside treats the look and leaves the cause.
Read about root canal treatment.
Who whitening is for
Healthy teeth, healthy gums, and a colour that bothers you. That is the short version of a good candidate.
Whitening waits when any of these applies.
- There is untreated decay
- Gum disease is active or the gums are inflamed
- A tooth is cracked or a filling is leaking
- You already have significant sensitivity
- One tooth is darker than the others and has not been assessed
- You are pregnant or breastfeeding. Safety information is limited, so wait until afterwards
Most of these are about the order of treatment, not a refusal. The exam shows which applies to you.
Teenagers are handled differently, and peroxide-free colour correctors have been studied for that age group. Ask us before you buy anything for a young person.
What happens before whitening
- A conversation about what you want changed, in your words, not as a shade number.
- A review of your dental and medical information.
- An exam of your teeth and gums, because whitening an unhealthy mouth treats the wrong thing.
- A talk about limits, including which of your teeth will and will not change.
- A review of the options open to you.
- Planning the timing and aftercare, especially if a restoration needs replacing afterwards to match.
Setting real expectations is the most useful part of this appointment. Someone who knows in advance that their crown will not change is not caught out by it.
Thinking about whitening? Book a consultation or call (905) 821-8632.
Does it hurt, and what does it do to enamel?
Sensitivity during and after whitening is common. It is felt mainly with cold. Tell us if it does not settle, and tell us beforehand if your teeth are already sensitive, because we look for the cause first.
There are levers for sensitivity. Shorter gel times, more space between sessions and a desensitising fluoride gel all help, and the exam is where we find out which one you need. Ask about them before the appointment, not after it.
Gum irritation happens where gel touches the gum. A custom tray and proper isolation are what keep it off.
On enamel there is a measured answer, not a reassurance. A 2026 laboratory study bleached extracted human teeth with three in-office protocols. Surface hardness dropped 13% to 30% straight after treatment. After 28 days in artificial saliva it had come back to between 92% and 97% of where it started.
The light-activated protocol dropped most and recovered least. Those are teeth in a jar, not teeth in a mouth, so read the figures as a direction and not as a measurement of your enamel.
That is one reason less gel time on the tooth is worth asking about. A 2026 randomised trial gave forty people the same 37.5% hydrogen peroxide gel across three sessions a week apart, and the group given two eight-minute applications per session held its colour at one year as well as the group given three.
How long the result lasts
No whitening result is permanent. Teeth pick up stain again from the same things that stained them in the first place.
A 2026 trial tracked colour with a spectrophotometer at one week, six months and one year. Both protocols were still effective at a year, and measurable rebound showed from the six-month reading. Plan for touch-ups, not for a one-off.
What helps it last is unglamorous. Cutting back on the obvious culprits, rinsing with water after coffee, tea or red wine, not smoking, and keeping up with your cleanings.
Read about teeth cleaning.
What whitening will not fix
Shape and position. Bonding and veneers change shape and colour together. They are what you need when the concern is not really colour. Read about dental bonding and dental veneers.
A restoration that stops matching. Whitening the teeth around a tooth-coloured filling or crown makes that restoration look darker by comparison. It did not change and everything around it did. Whiten first and match the restoration to the result, because doing it the other way round means replacing the crown if it no longer matches.
Read about dental crowns.
Doing nothing is a real option. If your teeth are healthy and the colour bothers you less once it is explained, we will say so.
On over-the-counter and DIY whitening
Products bought without an exam carry a specific risk, and it is not really about the product. Nobody has looked at your teeth. Whitening over untreated decay, a leaking filling, active gum disease or a cracked tooth fixes none of them and can make sensitivity much worse.
Ill-fitting trays put gel on the gums, and that irritates them.
Charcoal toothpaste is a separate case. It works by abrasion, not by bleaching, and a 2026 surface-mapping study of charcoal dentifrices examined what that abrasion does to enamel. Scrubbing a tooth is not whitening it.
If you use a shop-bought product anyway, the exam beforehand is the useful part.
Dentistry on Britannia is a general dental practice. Our dentists are general dentists, not specialists in any RCDSO-recognised specialty.