Whitening is the only cosmetic option that removes nothing from the tooth. That is what sets it apart from crowns and veneers: if you do not like the result, your teeth simply return to how they were — nothing is permanently lost. So where the only complaint is colour, this is the first option to consider.
The in-clinic session takes one to two hours, needs no anaesthetic, and a single night’s stay is enough.
It does not work on every stain
Whitening acts on discolouration sitting on and within the enamel. On the yellowish tones left by coffee, tea, red wine and smoking, the result is usually satisfying.
Discolouration coming from inside the tooth is another matter — the kind linked to certain medicines taken in childhood, or a tooth that has darkened after root canal treatment. These do not respond in the same way, and call for a different approach.
Crowns, veneers and composite fillings are unaffected by whitening. If you have fillings or crowns at the front, the gap in shade becomes more obvious as your natural teeth lighten. Where that applies, the order matters: whiten first, then match the new filling to the result.
Why sensitivity happens
The gel works by passing through the pores in the enamel, and that passage can briefly irritate the nerve. The result is cold sensitivity that may last a few days. It is expected, and it does not mean lasting damage.
You may be advised to use a sensitivity toothpaste in the days beforehand. For patients who already have noticeable sensitivity, the dentist adjusts the strength or the duration.
How long does the result last?
Putting a figure on it would be misleading, because what decides it is largely your habits. In someone drinking several coffees a day and smoking, the colour returns much faster. Regular brushing, cleaning between the teeth and rinsing with water after staining drinks extend the result noticeably.
Is it the same as over-the-counter products?
No. The gels used in clinic are stronger, which is why the gums have to be protected first; without that protection the same strength is not safe at home. Low-concentration home products work more slowly and to a more limited degree.
How it works
The active ingredient in the gel breaks down the coloured molecules that have accumulated in the enamel and the dentine beneath it. The tooth is not painted, and nothing is layered over it: the existing discolouration is chemically lightened.
That is why results differ from tooth to tooth. In the same mouth one tooth may lighten markedly while its neighbour responds less; enamel thickness and the type of discolouration vary between people, and even between teeth.
In the clinic the gums are sealed with a protective barrier first. That step cannot be skipped: the concentration used can cause temporary burning and blanching of gum tissue. It is also why low-concentration home products work more slowly.
The first 48 hours
Straight after the procedure the pores in the enamel are temporarily more open. That means staining substances take hold more easily than usual — making these two days the most important for protecting the result.
- Avoid coffee, black tea, cola and red wine
- Put off dark foods such as tomato sauce, soy sauce and curry
- Smoking undoes the result faster than anything else in this window
- Skip coloured mouthwashes and coloured toothpaste
- If you have sensitivity, stay on a sensitivity toothpaste for a few days
Making the result last
Some colour return is inevitable; what decides the pace is habit. In someone drinking several coffees a day it comes back noticeably faster than in a patient who had the same treatment without that habit.
One simple habit helps: rinse with water after a staining drink. Do not brush immediately — enamel softens briefly after acidic drinks, and brushing right then increases wear. Waiting half an hour is better.
The other way to extend it is regular professional cleaning. A good part of teeth looking dull is hardened surface plaque, and that only comes off in the clinic.
Does whitening damage the teeth?
Done under supervision at an appropriate concentration, no lasting damage to enamel is expected. The risk comes from uncontrolled use: high-concentration products bought online, applied often and for long periods, can wear both enamel and gums.
Can I have it done while pregnant?
Whitening is normally postponed during pregnancy and breastfeeding. That is not because harm has been shown, but because there is not enough safety data for these periods — avoiding elective procedures is the standard approach.
How often can it be repeated?
Maintaining the result is preferred to repeating it often. If you feel you need a top-up, ask your dentist — they will set the interval based on your enamel and any sensitivity. Repeating it every few months is not advised.