What we liked
- Home kits genuinely remove surface stain from coffee, tea and tobacco
- Lower-concentration gels tend to cause less sensitivity than higher-strength treatments
- Refill packs keep the running cost low
What we did not
- No effect on the underlying shade of the teeth
- Results fade without maintenance
- Instructions routinely overstate what a home kit can achieve
The gap between what whitening products claim and what they do is the widest in oral care. So the useful question is not “does it whiten” but “which kind of whiteness are we talking about”.
There are two, and they behave completely differently.
Extrinsic stain
Coloured compounds from coffee, tea, red wine and tobacco bind to the pellicle layer on the surface of the enamel. This is what a home kit, a whitening toothpaste or a hygienist’s polish can remove.
It is also what most people are actually looking at when they decide their teeth have gone yellow.
Intrinsic colour
This is the shade of the dentine underneath the enamel. No gel you apply at home changes it meaningfully. That requires a dentist, a higher concentration, and often a light source.
This is the part the packaging avoids saying. A home kit operates almost entirely on extrinsic stain. That is a real benefit — but if your complaint is the underlying shade of your teeth, no home product will fix it.
What actually changes the result
Concentration. Higher peroxide concentrations work faster and cause more sensitivity. Lower concentrations need more sessions. There is no free lunch here.
Tray fit. A tray that does not seal against the gum line leaks gel onto the gums, which is where most sensitivity complaints come from. A well-fitting tray at low concentration beats a loose tray at high concentration.
Consistency. Two weeks of daily use does more than two months of occasional use. If you will not keep it up, do not start.
Maintenance. This is the cost nobody mentions. Without periodic top-up use, most of the visible improvement fades. Budget for refills, not one purchase.
What to avoid
Any claim about “clinical” or “dental-grade” whitening on a consumer product. If it were dental grade, it would not be sold without a professional.
Before-and-after imagery. In this category it is routinely produced with different lighting, different white balance, or a filter. It is not evidence.
Anything promising a shade change by number. The numbers on a shade guide do not correspond reliably to what a home kit does.
What a home kit can honestly claim
It removes surface staining from coffee, tea and tobacco. It does so with mild and temporary sensitivity if used as directed. It will not change the colour of your teeth, and it will not last without maintenance.
If that is what you want, a home kit is a sensible purchase. If you want your teeth to be a different colour, that is a dental appointment, not a product.