Teeth Whitening at the Dentist or at Home? And Why It Made My Teeth Sensitive
Updated: 6 days ago
Teeth whitening, which dentists also call bleaching, lightens the natural colour of your teeth with a peroxide gel, either in trays you wear at home or in a supervised session in the dental chair. Whichever you pick, it can leave your teeth temporarily sensitive, and it only works on natural tooth, not on crowns or fillings.
I don't love the colour of my teeth. What can I do about it? I've tried teeth whitening and it didn't work. Or actually, the other time I tried, it made my teeth super sensitive. What do I do? It is something we get asked almost every day, so let's talk a little bit more about teeth whitening. My name is Dr. Kevin Zhang. This is Meraki Dental in South Surrey.
The short version
• At home or in the chair, the active ingredient is the same. The difference is speed and supervision: take-home trays are slow and steady, in-office is quick.
• Any whitening can cause some sensitivity. In-office tends to cause a little more, so if your teeth are already sensitive, start with take-home.
• The lights only speed things up a little. You do not need one.
• Whitening toothpaste only helps with surface stain.
• A free whitening consult shows which route fits. Teeth whitening in South Surrey.
Written from Dr. Kevin Zhang's own explanation. Dr. Kevin is a general dentist and co-owner at Meraki Dental in South Surrey. Reviewed against the sources listed below on 7 October 2026.
What is the difference between whitening at the dentist and at home?
Speed and supervision, not the ingredient. Whether it is a gel, a solution or a light-activated system, the active ingredient in teeth whitening is exactly the same. Health Canada describes the products sold here in the same terms: they generally use peroxide or peroxide-generating compounds, mostly hydrogen peroxide or carbamide peroxide, and in general the more peroxide, the greater the whitening power. What changes is how it gets onto your teeth, and who is in charge of it.
Take-home trays. You put the gel in your trays and wear them for half an hour to 45 minutes. It takes multiple, multiple sessions. I usually recommend five to ten, every other day or so, for a couple of weeks. Then you take a break, and go at it again if you would like more results.
Take-home whitening is almost like exercising. You have to keep up at it. It's not one and done. You have to maintain afterwards as well.
They do work really, really well, and they are proven to be very effective over a longer period of time. The research agrees on the first part. A Cochrane review of 71 trials of home whitening found the bleaching products whitened teeth better than a placebo over short periods, from two weeks to six months. It rated the certainty of that evidence low to very low, and the trials varied too much to say which product or schedule is best, so read it as "it works" rather than "here is exactly how well".
In-office. You are in the chair, we monitor and supervise the session, and we put a stronger solution on your teeth. It is quick, very effective, and you can see the results right away. Because it is supervised, we follow the instructions on your behalf. The downside is that the in-office ones tend to make the teeth a little bit more sensitive.
Same ingredient, two ways to use it. The tabs show pace, not how light your teeth will get. The same information is in the table below.
Take-home | In-office | |
Where | At home, in trays | In the chair, supervised |
Each session | 30 to 45 minutes | One visit |
How many | Five to ten, over a couple of weeks | One |
Strength | Lower | Stronger |
Results | Build up slowly | Right away |
Sensitivity | Builds more slowly | A little higher |
Do the lights in teeth whitening actually do anything?
A little, on speed. Shocking news: those lights don't do a ton. They do accelerate the process a little bit, but you don't need the light to whiten your teeth.
The research lines up with that. The Canadian Dental Association's position statement on tooth bleaching says the current literature does not indicate that power- or light-assisted bleaching produces whiter teeth, although the bleaching process occurs more quickly with these methods. A 2018 systematic review and meta-analysis of 21 randomized trials found no significant difference in colour change, or in the risk and intensity of sensitivity, between in-office gel used with a light and without one.
In plain terms, the gel does the whitening and the light is optional.
Is it better to whiten at home or at the dentist?
It depends on you. There is really no right or wrong answer. If you are the discipline type and you don't mind doing it at home by yourself, do the take-home one. If you would rather have it quick and supervised, with results you can see right away, in-office is the one. Your teeth's sensitivity is the other thing that decides it, so here is how it breaks down:
If this sounds like you | Start with |
Your teeth are fairly sensitive to begin with | Take-home trays, slow but steady |
Your teeth never give you trouble with temperature | In-office is a great option |
You are the discipline type and happy to do it yourself | Take-home trays |
You want it quick and supervised | In-office |
Not sure which one suits your teeth?
30 minutes, at no cost. We talk through the options and what is best for you. More on our teeth whitening page.
Why did whitening make my teeth sensitive?
Because the ingredient that lightens a tooth also reaches the nerve.
Any type of whitening solution you decide to go with will generate some sensitivity on teeth. That's just the nature of how teeth whitening works.
The ADA explains why: the peroxide in the whitener gets through the enamel to the soft layer of dentin and irritates the nerve of your tooth. In most cases the sensitivity is temporary. The ADA's review of whitening puts some numbers on it: mild to moderate sensitivity can occur in up to two-thirds of users in the early stages of bleaching, and with tray-based treatment it may start two to three days in and usually resolves by the fourth day after treatment.
Pace changes how it feels. The take-home ones are slower and a lower concentration, so they tend to cause the sensitivity much more slowly. The in-office one, the one session and I'm done type of solution, does tend to make the teeth a little bit more sensitive. Again, there is no right or wrong. The research gives that a little backing: a 2025 update of a systematic review of randomized trials found the intensity of sensitivity was lower with at-home bleaching, though it graded that evidence as low quality, and the risk of getting sensitivity at all did not differ between the two.
If your teeth are already fairly sensitive, I would recommend starting with the take-home, slow but steady option, because it tends not to make the sensitivity much worse, fast. If your teeth are really good and never give you trouble with temperature, the in-office one is a great option, because it will most likely not make your teeth that sensitive.
If your teeth are sensitive right now, after a round of whitening, Health Canada suggests three things: cut the wear time in half, for example 30 minutes instead of 60; stop for two or three days and then start again; or stop altogether and see an oral health professional. The ADA's patient site adds that you can delay treatment and try again. If it does not settle down, stop whitening and call us.
How long does teeth whitening last?
It varies, and nobody can honestly give you one number. The sources give a range:
The Canadian Dental Association's position statement says the effects of bleaching can be expected to last up to two years, depending on lifestyle choices such as smoking and staining foods and drinks.
Health Canada, writing about home kits, says the results may last up to six months.
In one two-year trial of tray whitening, teeth were still significantly lighter than before at two years, although more than two-thirds of the people in it reported some fade, mild to moderate.
Our own teeth whitening page puts it plainly: it can last anywhere from a few months to years. What decides where you land is mostly what goes in your mouth. The ADA lists coffee, tea, red wine and tobacco among the main causes of staining.
That is why I make the exercise analogy: you have to maintain it afterwards. Topping up has its own limit, though. The CDA says the long-term effects of repeated bleaching, especially if products are used inappropriately or excessively, are not yet fully understood and may include tooth pitting and damage to the nerve. So ask us how often is sensible for you, rather than topping up on your own.
Does whitening toothpaste work?
Only on surface stain. Whitening toothpaste doesn't tend to work as well. Most of them work through the abrasives in the ingredients, basically like very fine sand in the toothpaste that we scrub our teeth with. If the colour of your teeth is not from cigarette stain, or very heavy coffee stain, whitening toothpaste won't make too much of a difference.
The ADA says the same: whitening toothpastes primarily rely on abrasives to remove surface stains, and products like them will not have a significant impact on the colour inside the tooth. A peer-reviewed review of whitening toothpastes names the abrasive system as one of the key functional ingredients. And the CDA's patient page says surface whiteners are limited to surface stains and should not replace a professional cleaning. To change the colour inside the tooth, you need a peroxide gel, at home or in the chair.
Is whitening toothpaste bad for your teeth?
Not necessarily, though I am cautious. We generally don't recommend whitening toothpaste very much, because they don't work too well, and over time they tend to be a bit too abrasive on the teeth.
The guidelines are a little more relaxed. The CDA says the abrasives in whitening products are often only finer versions of what is used in regular toothpaste, so they are unlikely to cause excessive wear. The ADA treats toothpaste at or below 250 on the Relative Dentin Abrasivity scale as safe and effective, and says lifelong use of proper brushing technique with one produces limited wear to dentin and virtually no wear to enamel. That scale is named for dentin, the softer layer under the enamel that can be exposed when enamel wears or gums recede.
Where we all agree is the main point: it only works on surface stain.
Who should not whiten their teeth, or should wait?
A few people should wait, or see a dentist first.
If you are pregnant. The CDA says to put whitening off until after pregnancy, since bleaching products have not been tested in pregnant women. Health Canada also says to talk to an oral health professional first.
If your child is under 12. The CDA says bleaching products should not be used for children under 12.
If you have gum disease or unfilled cavities. Health Canada's advice is to consult an oral health professional before exploring whitening, so the problem is looked at first.
If your teeth are sensitive to begin with. Health Canada says to see an oral health professional first, and my advice is to start with take-home trays, slow but steady.
If you are tempted to repeat it often. See the CDA's caution on repeated bleaching above, and ask us how often is sensible.
Our whitening page says the first step is an examination, with a goal and a baseline colour set before you start, so anything on this list gets seen before any gel goes on.
When is whitening not the fix?
When the colour is not something a gel can change. A few common cases:
Crowns, veneers and fillings. Whitening works only on natural teeth, not caps, crowns, veneers, fillings or dentures. The CDA adds that crowns, fillings and other dental materials are unaffected by bleaching compounds and may appear darker than the teeth around them once those have been whitened.
Grey or brown teeth. The ADA's patient site says yellow teeth will probably bleach well, brown teeth may not respond as well, and teeth with grey tones may not bleach at all. Stains from tetracycline, a medication, can be diminished but may take three to four months of nightly treatment, on average, and the CDA warns that irregular discolouration from medication, ageing or fluorosis can give irregular and unsatisfactory results.
One tooth that is darker than the rest. A knock to the mouth can darken a tooth, and so can a root canal. The CDA says non-vital bleaching can lighten a tooth from the inside out, and that you should see a dentist first, especially with root canal treatments, crowns or extremely dark stains on the front teeth.
What whitening changes, and what it does not. The same information is written out above.
When whitening is not enough, the conversation moves to covering the tooth. Dental bonding helps repair chipped or discoloured teeth, and veneers can change the colour of teeth that whitening will not shift. I go through composite and porcelain in our veneers post, and the advice there matches this one: if colour is the only problem, try whitening first. The full menu is on our cosmetic dentistry page.
How much does teeth whitening cost, and does insurance cover it?
The CDCP does not cover it, and we do not put a price in a blog post. The Canadian Dental Care Plan's Dental Benefits Guide lists cosmetic treatment, including teeth whitening, among the services that are always outside the plan. Private plans vary, so it is worth checking yours before you start.
What it costs depends on which route suits your teeth, and the honest way to get a number is to ask. Our whitening page says our fee structure is transparent and that we help you find out what your dental insurance will cover beforehand. The consult itself is free. If you are on the CDCP, our guide to what the CDCP covers shows what it does pay for.
Want a number for your own teeth?
Teeth whitening at Meraki Dental in South Surrey
A treatment room at Meraki Dental, South Surrey.
A few practical things:
A free whitening consult. We always offer a complimentary meet and greet and consult when it comes to whitening and other procedures. Our online booking lists it at 30 minutes. Come and have a chat about the options and what is best for you.
How a take-home case starts. Our teeth whitening page says we examine your teeth first, set a goal and a baseline colour, give you detailed instructions, and check progress together in the office.
Insurance. We bill insurance carriers directly, and we help you find out beforehand what your plan will cover.
Languages. Between us you can be seen in English, Mandarin or Punjabi. Meet the team.
Open Tuesday to Saturday, 9am to 5pm. 2940 King George Blvd, Unit 100, Surrey, with free parking on site and on the street.
Rated 4.9 on Google from 143 reviews, at the time of writing.
Frequently asked questions
Is it better to whiten your teeth at the dentist or at home?
Neither is better for everyone, and there is no right or wrong answer. The active ingredient is the same. Take-home trays are slow and steady: five to ten sessions, every other day or so, over a couple of weeks. In-office whitening is quick, supervised and shows results right away, but tends to make teeth more sensitive. If your teeth are already sensitive, start with take-home.
Why are my teeth sensitive after whitening?
The peroxide that lightens the tooth passes through the enamel to the dentin and can irritate the nerve, according to the ADA. Any whitening can cause some sensitivity, and in-office tends to cause a little more. It is usually temporary. If it bothers you, Health Canada suggests halving the wear time or pausing for two or three days. If it does not settle, stop and call us.
How long does teeth whitening last?
There is no single number. The Canadian Dental Association says the effects can be expected to last up to two years, depending on smoking and staining foods and drinks. Health Canada says home-kit results may last up to six months. Take-home whitening is more like exercise than a one-off fix: you have to maintain it afterwards.
Does whitening toothpaste actually work?
Only on surface stain. Whitening toothpaste works mainly through abrasives, which are like very fine sand. It can help with cigarette stain or very heavy coffee stain, but it will not change the colour inside the tooth, and we generally do not recommend it very much. A peroxide gel from a dentist is what changes the tooth's own colour.
Is whitening toothpaste bad for your teeth?
I am cautious: over time whitening toothpaste can be a bit too abrasive. The guidelines are more relaxed. The ADA treats toothpaste at or below 250 RDA as safe and effective, and the Canadian Dental Association says the abrasives are often finer versions of those in regular toothpaste. Everyone agrees on the main point: it only helps with surface stain.
Do the lights in teeth whitening make it work better?
A little, on speed. The lights accelerate the process a little bit, but you do not need one to whiten your teeth. The Canadian Dental Association says the evidence does not show light-assisted bleaching gives whiter teeth, only faster. A 2018 review of 21 trials found no significant difference in colour change or sensitivity with or without a light.
Who should not whiten their teeth?
Wait if you are pregnant: the Canadian Dental Association says to defer whitening until after pregnancy, since the products have not been tested in pregnant women. Children under 12 should not use bleaching products. See a dentist first if you have gum disease, unfilled cavities or sensitive teeth. Crowns, veneers and fillings will not whiten.
Book a free whitening consult in South Surrey
So, take-home, in-office, or neither? There really is no right or wrong answer, and there are lots of options. If you would like to talk more about whitening and what is the best option for you, come and have a chat. We will welcome you with open arms, and we can't wait to meet you.
Or call 604-385-1823. Meraki Dental, 2940 King George Blvd, Unit 100, Surrey, BC V4P 0E4. Tuesday to Saturday, 9am to 5pm. Rated 4.9 from 143 Google reviews at the time of writing.
Sources: Health Canada, The Safe Use of Home Tooth Whitening Kits (updated February 2020). Canadian Dental Association, Position on Tooth Bleaching and Whitening (approved November 2007, reaffirmed June 2013) and Teeth Whitening (patient page). American Dental Association, Whitening (last updated 16 August 2022), Toothpastes and MouthHealthy, Teeth Whitening. Eachempati P and colleagues, Home-based chemically-induced whitening (bleaching) of teeth in adults, Cochrane Database of Systematic Reviews, 2018. Maran BM and colleagues, In-office dental bleaching with light vs. without light, Journal of Dentistry, 2018. de Geus JL and colleagues, At-home vs in-office bleaching: an updated systematic review and meta-analysis, Operative Dentistry, 2025. Meireles SS and colleagues, a double-blind randomized clinical trial of two carbamide peroxide tooth bleaching agents, 2-year follow-up, Journal of Dentistry, 2010. Joiner A, Whitening toothpastes: a review of the literature, Journal of Dentistry, 2010. Government of Canada, Canadian Dental Care Plan Dental Benefits Guide, Appendix E: Exclusions (effective 1 April 2026). All read 7 October 2026. Consultation length from Meraki Dental's online booking and review count from Google, 7 October 2026.
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