At-Home vs In-Chair Whitening
How whitening at the dentist compares with a home kit on strength, time, results, cost and supervision.
In-Chair Whitening
In-chair whitening is done by a dental professional. The NHS says it takes one appointment of around 1 to 2 hours, often with a light or laser. The American Dental Association describes gels with high peroxide concentrations, sometimes used with a light intended to speed up and enhance bleaching, and “power bleaching” with concentrated hydrogen peroxide applied for up to 30 minutes.
A dentist can also make trays that fit your teeth for you to use at home with a professional gel, usually for 2 to 6 weeks (NHS). The NHS says whitening is not permanent but may last around 3 years. Prices vary by clinic, so ask for a quote.
At-Home Whitening
Home kits are sold directly to you, and the strength allowed depends on where you live. In Australia, products with up to 6% hydrogen peroxide can be sold with safety warnings (Dental Board of Australia, Australian Dental Association). In the UK and EU, the limit is 0.1% hydrogen peroxide, so home kits usually use PAP (GDC). We found no national limit in the US sources we checked.
SmilePro's kit, for example, uses 6% hydrogen peroxide in Australia and the US and PAP in the UK, with 30 treatments of 10 minutes, for A$104.50 in Australia, £54.50 in the UK and US$77 in the US. SmilePro says it whitens teeth by up to 8 shades in 7 sessions, with full results typically within a week. The NHS says shop-bought kits may not work as well as dentist whitening and may harm teeth and gums, so have a check-up first.
Comparison
| In-chair | At home | |
|---|---|---|
| Who does it | A dental professional | You |
| Strength | Higher concentrations, chosen by the dentist | Up to 6% hydrogen peroxide in Australia; 0.1% in the UK and EU |
| Time | One visit of around 1 to 2 hours (NHS) | Short daily sessions (SmilePro: 10 minutes) |
| Cost | Varies by clinic | SmilePro: A$104.50 in Australia, £54.50 in the UK and US$77 in the US |
| Results | Not permanent; may last around 3 years (NHS) | The brand's own claims (SmilePro: up to 8 shades in 7 sessions) |
| Supervision | A dentist checks your teeth first | Self-directed; the NHS advises a check first |
Verdict
In-chair whitening uses stronger gels under a dentist's supervision, and in the UK and EU it is the only way to use more than 0.1% hydrogen peroxide. A home kit fits around your day, but the strength allowed is lower in the UK and EU, and the evidence on how well home whitening works is of low to very low certainty (Cochrane 2018). Whichever you choose, have a dental check first.
Is whitening safe?