Think of baking soda as a polish rather than a bleach. It is good at loosening the brownish film that coffee, tea and red wine leave on enamel, so teeth can look cleaner and a little brighter. It has no ingredient that reaches the colour inside the tooth, though, so the natural shade underneath stays where it is.
What baking soda can and cannot do for tooth colour
Baking soda is sodium bicarbonate. When you brush with it, the fine crystals rub away stain sitting on the outer surface of the enamel. A literature review of baking soda toothpastes (Li, Journal of the American Dental Association, 2017) concluded that they are effective and safe for removing stain, and that several clinical studies found them more effective at stain removal than some more abrasive toothpastes without baking soda.
The same review draws a clear line between two ways of whitening. Abrasives such as baking soda work mechanically, by lifting stain off the surface. Peroxide gels work chemically, by passing into the tooth and breaking down coloured molecules. Baking soda only does the first.
Is your discolouration on the tooth or in it?
That distinction decides whether baking soda is worth trying. Surface stain tends to collect along the gumline, near the biting edges and in the gaps between teeth, and it is usually darker in those spots than across the middle of the tooth. It comes from things like coffee, tea, red wine and smoking, and it generally lightens noticeably after a professional clean. Our article on how coffee, wine and tea stain teeth explains how it builds up.
Colour from inside the tooth looks more even, often a uniform yellow or grey. It can reflect your natural shade, changes with age as the enamel thins, certain medicines taken while teeth were forming, or a single tooth that has darkened after an injury. Brushing will not shift any of these. Fillings, bonding, crowns and veneers also keep their own colour regardless of what you brush with. Our guide to intrinsic and extrinsic tooth staining covers the two types in more depth.
Baking soda is one of the gentler abrasives
Every toothpaste contains something mildly abrasive to help clean the teeth, and how abrasive it is matters for long-term wear. A review in the same 2017 journal issue (Hara and Turssi) found that baking soda is low in abrasiveness by nature, because its crystals are softer than enamel and dentine. Some baking soda toothpastes add other cleaning agents that raise their abrasiveness, but the authors reported that even these formulations sit well within the safety limits set by regulators.
So the powder itself is unlikely to wear your teeth when used sensibly. Problems tend to come from what it is mixed with and how hard it is scrubbed.
How people get into trouble with it
Most of the risk sits in the home recipes that circulate online:
- Adding lemon juice or vinegar. Acid softens the enamel surface, so scrubbing an acidic, gritty paste over the teeth softens and abrades enamel at the same time. Our article on lemon water and enamel explains the effect.
- Scrubbing hard with a firm brush. Heavy pressure can do more damage to enamel and gums than the baking soda itself.
- Brushing exposed roots. Where gums have receded, the root surface is much softer than enamel. A soft brush and regular fluoride toothpaste are kinder to these areas.
- Swapping it for toothpaste. Plain baking soda has no fluoride, so on its own it does nothing to protect against decay.
- Mixing up homemade peroxide pastes. The strength is unknown, and the mixture can irritate the gums.
Other home options carry similar trade-offs. Many charcoal products also lack fluoride, which we discuss in is charcoal toothpaste safe, and our overview of natural teeth whitening remedies looks at the rest.
A side benefit: it helps neutralise acid
Baking soda is alkaline. A review of the evidence (Zero, Journal of the American Dental Association, 2017) reported that it can quickly reverse the drop in plaque acidity that follows a sugary snack, and that the effect is greatest when it is used soon after the sugar and depends on how much baking soda the product contains. The author suggested people with a dry mouth may benefit most from a fluoride toothpaste containing baking soda, while noting that more evidence is needed on its long-term effect on decay.
Getting the benefit safely
The simplest approach is a toothpaste that contains both baking soda and fluoride, used twice a day with a soft brush. That gives you the stain-lifting and acid-buffering effects and keeps the decay protection fluoride provides.
If you prefer plain baking soda, treat it as an occasional extra. Use a small amount on a damp soft brush, brush gently, then brush again with your usual fluoride toothpaste. Keep acids and peroxide out of it.
When you want a lighter shade, not just less stain
Changing the colour inside a tooth needs a peroxide gel. In Australia, products with more than 6 per cent hydrogen peroxide or 18 per cent carbamide peroxide can be supplied and used only by registered dental practitioners, as the Australian Dental Association's policy on teeth whitening sets out. A dentist can check first whether whitening suits your teeth, because it will not change the colour of fillings or crowns and some types of discolouration respond better than others.
At Lumi Dental our whitening options are Lumi Home, which is take-home whitening, and Lumi Refresh and Lumi Radiance, which combine an in-chair session with take-home whitening. Results vary from person to person and we do not promise a particular shade. The teeth whitening page explains how it is planned, our comparison of professional and at-home whitening sets out the differences, and our article on whether whitening damages enamel looks at the research. For whitening toothpastes sold in supermarkets, see does whitening toothpaste work.
What people ask about baking soda
Can I use a baking soda toothpaste every day?
Yes, if it also contains fluoride. Plain baking soda is better kept for occasional use and should not replace your fluoride toothpaste.
Is it better than whitening toothpaste?
Most whitening toothpastes also work mainly by removing surface stain, so they are in the same category. Neither will bleach the colour inside the tooth.
Why do my teeth look the same after weeks of using it?
If brushing with baking soda has made little difference, the colour is probably inside the tooth or in an existing filling or crown. A dentist can tell you which, and whether whitening or another option would help.
If you would like to know what is realistic for your teeth, book a free cosmetic consult at Lumi Dental, or see our current offers.
