How does teeth whitening actually work?
Whitening works through a chemical process called oxidation. The active ingredient, typically hydrogen peroxide or carbamide peroxide, penetrates the outer layers of tooth enamel and breaks down the molecular chains of stain compounds that have accumulated over time. The tooth enamel itself isn't damaged by this process when the treatment is applied correctly.
The key variables are:
- Concentration: professional gels are stronger than anything available in a pharmacy
- Contact time: how long the gel stays against the tooth surface
- Fit: custom trays create an even seal that prevents gum exposure and ensures consistent coverage
Both our in-office and take-home options use professionally formulated gels. The difference is how quickly the result arrives, not whether it works.
In-office whitening: what the appointment looks like
In-office whitening is done at the clinic in a single session, usually 60 to 90 minutes. We start by protecting your gums and soft tissues, then apply the whitening gel to the tooth surfaces. Most patients leave noticeably lighter than when they arrived.
In-office treatment is a good option if:
- You want results quickly, before a wedding, event, or photo
- You prefer having the whole process supervised rather than managing it at home
- Your teeth are significantly stained and you want to see how much can be achieved in one visit
Take-home whitening: the at-home option
Take-home whitening uses custom trays made from impressions of your teeth, paired with professional-grade whitening gel. You wear the trays for a prescribed amount of time each day, typically 30 to 60 minutes, over one to two weeks.
Take-home whitening is often preferred by patients who:
- Want to manage the process at their own pace
- Have teeth that are sensitive and benefit from a slower, lower-concentration approach
- Want to maintain their result with occasional touch-ups over time
The trays are yours to keep. Once you've achieved your desired shade, you can do periodic maintenance treatments with new gel from us, no need to start from scratch.
What's realistic to expect
Whitening works well on yellow and brown surface staining, the kind caused by coffee, tea, wine, and ageing. It works less predictably on:
- Grey or blue-grey discolouration, often caused by old trauma or certain medications (tetracycline, for example)
- White spots from fluorosis or early decay, these may become more noticeable rather than less with whitening
- Existing restorations: crowns, veneers, and composite bonding won't change colour
We'll look at your teeth before recommending whitening and tell you honestly what kind of result is achievable for your specific situation. If veneers or bonding would give you a better outcome, we'll say so.
Sensitivity: what to expect and how we manage it
Tooth sensitivity during or after whitening is common but manageable. Most patients describe it as a brief, sharp sensation when the teeth encounter cold air or cold drinks. It usually resolves within 24 to 48 hours.
To reduce sensitivity, we may:
- Apply a desensitising gel before or after treatment
- Recommend using a sensitivity-formulated toothpaste in the week before treatment
- Adjust the concentration or session length for patients who are particularly prone to sensitivity
If you already experience noticeable sensitivity day-to-day, please mention this before your whitening appointment. It's something we can work around, not a reason to skip treatment entirely.
Maintaining your result
The most common cause of whitening fading is simply exposure to staining foods and drinks over time. Coffee, tea, red wine, and tobacco are the main culprits. You don't have to give them up, rinse with water afterwards and keep your regular hygiene appointments.
Using your custom trays for a brief maintenance session every few months is usually enough to keep the result looking fresh.
Ready to get started? Book a cosmetic consultation and we'll assess your teeth, talk through your options, and help you decide which approach fits your goals.