How does professional teeth whitening work?
Teeth darken over time as pigments from coffee, tea, red wine, tobacco and some foods build up inside the enamel and dentin. Whitening gels contain hydrogen peroxide or carbamide peroxide, which release oxygen that breaks down these pigment molecules into smaller, less visible ones. The tooth structure itself is not removed; the color is lightened from within.
In-office whitening at Seoul E&D Dental Clinic in Sanbon, Gunpo uses a professional gel together with a KFDA-approved whitening device. Because the procedure is supervised, the gums can be protected and the treatment adjusted to how your teeth respond. Professional supervision also means that any tooth or gum problem discovered beforehand can be treated first, rather than being aggravated by the whitening gel.
Whitening versus whitening toothpaste
Most whitening toothpastes work by polishing surface stains with mild abrasives. They can make teeth look cleaner but do not change the internal shade of the tooth. Professional whitening targets the deeper discoloration. Removing surface tartar and stain with professional scaling beforehand also helps the gel work evenly.
Who is teeth whitening suited for?
Whitening generally works well for:
- Yellowish discoloration from aging or diet
- Staining from coffee, tea, wine or smoking
- Adults with healthy teeth and gums who want a brighter shade
It is less predictable for grey discoloration caused by certain medications, for teeth darkened after nerve damage, or for white spots and enamel defects. Whitening may be postponed during pregnancy or breastfeeding, and active cavities or gum disease should be treated first.
Importantly, whitening does not change the color of crowns, veneers or fillings. If you have visible restorations, they may look darker than your newly whitened teeth and might need replacing afterwards. Whitening is often done before composite bonding or new crowns so they can be matched to the lighter shade.
The whitening process at E&D Dental
- Check-up. We examine your teeth and gums, using the Q-ray intraoral camera to look for plaque, cavities and cracks that could cause sensitivity during whitening.
- Shade record. Your starting shade is recorded so changes can be compared, and we discuss what level of change is realistic for your teeth.
- Cleaning. If needed, scaling is done beforehand to remove tartar and surface stain.
- Protection. The lips and cheeks are held back and a protective barrier is applied to the gums.
- Whitening session. The gel is applied to the front surfaces of the teeth and activated with the KFDA-approved whitening device. The gel may be refreshed during the session.
- Review. The gel is removed, the new shade is compared with the starting shade, and we discuss whether further sessions would be useful.
Some people see a noticeable change after one session, while others need more than one visit. Results vary from person to person. Naturally yellow-toned teeth tend to respond more readily than grey-toned teeth, and the final shade is also influenced by the thickness of your enamel.
Aftercare: the first 48 hours and beyond
Teeth are more prone to absorbing color right after whitening. For about two days, try to avoid:
- Coffee, black tea, red wine and cola
- Strongly colored sauces such as kimchi stew, curry, soy sauce and gochujang
- Smoking
A sensitivity toothpaste can help if your teeth feel sensitive. Long term, rinsing with water after staining drinks and regular cleaning visits help the result last longer. Touch-up sessions can be considered when the shade begins to fade.
Risks and limitations
The most common side effect is temporary tooth sensitivity, often described as short, sharp twinges, which usually settles within a few days. Gum irritation can occur if gel contacts soft tissue. Results are not permanent, and the degree of whitening cannot be predicted exactly. Over-frequent whitening is not recommended. People with pre-existing tooth sensitivity should mention it so the approach can be adjusted.
Why patients in Sanbon and Gunpo choose E&D Dental for whitening
- Whitening carried out with a KFDA-approved whitening device under dental supervision
- An examination first, so cavities, gum issues and restorations are considered
- Whitening, scaling and aesthetic restorations available together for a coordinated result
- Saturday morning and Monday and Thursday evening appointments, about 5 minutes on foot from Sanbon Station on Line 4
International residents can ask about arranging English communication when booking. Read more in our guide to professional whitening, or contact E&D Dental to book a whitening consultation.