01What is teeth whitening?
Teeth whitening is a chemical procedure that uses hydrogen peroxide or carbamide peroxide to oxidize and break down pigments within the tooth, making the tooth color lighter.
Tooth color is largely determined by two factors: first, the thickness and translucency of the outermost layer, enamel. Second, the natural color of the underlying dentin. Enamel is nearly colorless and translucent; most yellow or gray tones you see are the underlying dentin showing through.
The active ingredient in teeth-whitening agents is hydrogen peroxide (H₂O₂) or carbamide peroxideThese agents pass through the enamel and into the dentin, where they oxidize pigment-bearing molecules (mainly large organic chromophores) into smaller, lighter-colored molecules, making the teeth appear whiter.
Important — whitening agents do not "grind away" the surface
This is a common misconception. Whitening is a chemical oxidation process; it does not file down or damage the tooth surface. When performed properly, it does not cause irreversible damage to the enamel.
Shades that respond well to whitening vs. those that do not
| Tooth color type | Main cause | Whitening response |
|---|---|---|
| Extrinsic staining (black spots, brown bands) | Coffee, tea, wine, smoking, pigmented drinks | Largely removable with Scaling (Dental Cleaning) and polishing alone |
| Yellowish teeth | Natural shade, aging, diet | Best whitening response (★★★) |
| Grayish teeth | Natural shade; after Root Canal Treatment | Moderate whitening response (★★) |
| Tetracycline staining | Antibiotic side effect in early childhood | Limited whitening response; Laminate Veneer recommended (★) |
| Hypoplasia (spots) | Developmental defect | Not suitable for whitening; Laminate Veneer or Composite Resin recommended |
02Types of Teeth Whitening — 4 methods
Broadly divided into four types—In-office Whitening, At-home Whitening, Internal Whitening, and Combination Whitening—with clear pros and cons for each.
1. In-office Whitening (Office Bleaching, In-office Bleaching)
Performed chairside at the dental office in a single session. A high-concentration hydrogen peroxide (15~40%) gel is applied to the teeth and activated with an LED or laser light source for about 60~90 minutes. With 1~3 visits, the average improvement is 3~6 shades (Vita shade guide), and results are the most immediate.
2. At-home Whitening (Home Bleaching, At-home Bleaching)
At the dental office, you receive a custom-fitted tray (tray)that is made to fit your teeth; you then place a low-concentration carbamide peroxide (10~22%) gel in the tray and wear it nightly for about 1~2 hours over approximately 2~4 weeks. Results appear gradually, but the average outcome is similar to in-office whitening and often lasts longer.
3. Internal Whitening (Walking Bleach)
Used to whiten a single tooth that has turned gray or brown after Root Canal Treatment. The access is reopened, a whitening agent is placed inside the tooth and temporarily sealed, then replaced after 3~7 days; this cycle is repeated 2~3 times. Not used on vital (living) teeth.
4. Combination Whitening (Combo)
First boost the shade with in-office whitening, then maintain and reinforce it yourself using an at-home tray. It is the most expensive option but offers the best effectiveness and longevity.
In-office vs. At-home Whitening comparison chart
| Category | In-office Whitening | At-home whitening |
|---|---|---|
| Treatment duration | 1 day (1~3 visits) | 2~4 weeks |
| Time per session | Approx. 60~90 minutes | 1~2 hours daily (while sleeping) |
| Hydrogen peroxide concentration | 15~40% (high concentration) | 10~22% (low concentration, carbamide peroxide) |
| Tooth sensitivity (side effect) | Common (approx. 60~80%) | Less common (approx. 30~50%) |
| Average cost (2026) | Approx. 300,000~500,000 KRW (approx. $219~$365) | Approx. 150,000~250,000 KRW (approx. $110~$183) |
| Duration of results | Average 1~2 years | Average 2~3 years (depends on home care) |
| Recommended for | Those who want fast results | Those who can maintain consistent home care |
03Teeth whitening costs (2026)
Because teeth whitening is cosmetic, it is not covered by Korean NHIS (out-of-pocket). Prices vary widely by clinic, region, and technique.
| Treatment type | Average cost per session | Total cost (course-based) |
|---|---|---|
| In-office whitening (1 session) | Approx. 200,000~300,000 KRW (approx. $146~$219) | 1 session or 1+1 booster 300,000~500,000 KRW (approx. $219~$365) |
| In-office whitening (3-session course) | — | Approx. 500,000~800,000 KRW (approx. $365~$584) |
| At-home whitening (tray + gel) | — | Approx. 150,000~250,000 KRW (approx. $110~$183) |
| Combination whitening | — | Approx. 500,000~800,000 KRW (approx. $365~$584) |
| Internal bleaching (single tooth) | — | Approx. 150,000~300,000 KRW (approx. $110~$219) |
| Scaling (Dental Cleaning) (when covered by Korean NHIS) | — | Patient copay 15,000 KRW (approx. $11) |
Be cautious of places that are too cheap
Rarely, "ultra-cheap whitening" is advertised at 50,000–100,000 KRW (approx. $37–$73). In such cases, these are often low-concentration, one-off products with little effect, or unverified products that can cause gum burns and prolonged tooth sensitivity. Proper professional whitening includes before/after photo comparison (Vita shade guide), gum protection, and application of desensitizing agents—steps that require an appropriate fee.
04Professional whitening process
Professional whitening starts with an accurate diagnosis, because the right method depends on the cause of discoloration.
Step 1: Diagnosis and suitability assessment (10 minutes)
The dentist checks tooth condition, causes of discoloration, the presence of cavities or gum disease, pregnancy status, and more. If it’s surface staining, Scaling (Dental Cleaning) alone may be enough; if it’s enamel hypoplasia or significant tetracycline staining, Laminate Veneer may be more effective.
Step 2: Pre-treatment photos + shade measurement (5 minutes)
We objectively record your current shade using the Vita shade guide (A1~D4, 16~28 steps) and a digital colorimeter. This data provides a quantitative basis to show changes after treatment.
Step 3: Gum protection (10 minutes)
Before applying the whitening gel, a light-cured gingival barrier resin is applied to the gums and oral mucosa. Because high-concentration hydrogen peroxide can cause a temporary burn if it touches the gums (turning them white with a stinging sensation), this step is very important.
Step 4: Apply whitening gel + light activation (60~80 minutes)
A 15~40% hydrogen peroxide gel is evenly applied to the tooth surfaces, then activated with a cool LED or laser for about 15~20 minutes. This is typically repeated 3~4 times. During the procedure, you’ll wear protective goggles and recline comfortably; there is no severe pain, but about 30~40% of patients feel sensitivity.
Step 5: Post-care + sensitivity management (15 minutes)
The gel is thoroughly rinsed off, and a fluoride or ACP (amorphous calcium phosphate) gel is applied to help prevent sensitivity. Shade and photos are recorded again immediately after treatment to confirm changes.
Step 6: At-home care guidance + next appointment (10 minutes)
You’ll receive guidance for the first 48 hours on the "White Diet"—limiting strongly pigmented foods and drinks such as coffee, tea, wine, curry, kimchi, and gochujang. At 1~3 weeks, we check the effect and decide on any touch-up whitening if needed.
05Side effects and how to manage them
Teeth whitening is relatively safe, but temporary side effects are common. Knowing them in advance makes things much easier.
1. Tooth sensitivity (the most common side effect)
About 60~80% of in-office patients and about 30~50% of home whitening patients experience sensitivity. This occurs because the whitening agent passes through enamel and temporarily stimulates the tiny tubules in dentin (dentinal tubules).
- What helps: Starting 2 weeks before treatment, use a toothpaste for sensitivity (contains potassium nitrate and sodium fluoride); for 48 hours after treatment, avoid cold drinks and cold air, brush with lukewarm water; pain relievers (acetaminophen) can be used for 1~2 days if needed
- Duration: Usually improves within 24~72 hours, with full recovery within 1 week at most
2. Gum irritation/burn
If gum protection is insufficient, a mild burn can occur, turning the gums white with a stinging sensation. It usually heals on its own within 2~3 days, but if pain is severe, please visit the dentist for care.
3. Uneven shade (blotches)
Each tooth has its own base color, and restorations (Composite Resin or ceramic) do not whiten. After whitening, the color difference between natural teeth and restorations can become more noticeable. In such cases, replacing restorations after whitening is recommended.
4. Rebound (Color Rebound)
It’s normal for teeth to look brightest right after treatment and then become slightly darker within a few days to 1 week. Immediately after whitening, teeth are temporarily dehydrated and appear whiter; as moisture is reabsorbed, the shade stabilizes. The final shade is assessed about 2 weeks after treatment.
Whitening is not recommended for:
- Pregnant or breastfeeding (insufficient safety data)
- Under 18 (larger pulp chamber, higher sensitivity risk)
- Severe cavities or gum disease (treat these first)
- Teeth with enamel hypoplasia or cracks
- Those with many large restorations or Crowns (they do not whiten)
- History of hypersensitivity to hydrogen peroxide
06How long does the whitening effect last
Whitening is not “once and for life.” How long it lasts varies greatly with diet and home care.
Average maintenance periods are roughly as follows.
| Maintenance Level | In-Office Teeth Whitening | At-Home Whitening | Combination |
|---|---|---|---|
| High Maintenance (limit staining foods, periodic touch-ups) | 2~3 years | 3~4 years | 4~5 years+ |
| Moderate Maintenance | 1~2 years | 2~3 years | 3~4 years |
| Poor Maintenance (heavy coffee and tobacco use) | 6 months~1 year | 1~1.5 years | 1.5~2 years |
8 tips to make your results last longer
- White Diet for 48 hours: For the first 48 hours after treatment, avoid staining foods and drinks (enamel is most porous during this time)
- Use a straw for staining drinks: Drink coffee, black tea, and cola with a straw to minimize contact with the front surfaces of your teeth
- Rinse for 30 seconds after meals: Rather than brushing immediately after a staining meal, rinse with water for 30 seconds and brush after 30 minutes
- No smoking: Smoking can shorten how long whitening lasts to less than half
- Regular Scaling (Dental Cleaning) (every 6 months): Periodically removes surface stains
- Have an at-home whitening tray: Do touch-up whitening for 2~3 days every 6~12 months
- Use whitening toothpaste as a supplement: About 2~3 times per week (daily use may increase abrasion)
- Check-up after 1 year: Monitor shade changes + add 1~2 touch-up sessions if needed
07When whitening doesn't work — Laminate Veneer · All-Ceramic alternatives
For shade issues that whitening cannot resolve, restorations (Laminate Veneer · All-Ceramic) are an alternative.
Laminate Veneer vs. Teeth Whitening Comparison
| Category | Teeth Whitening | Laminate Veneer (Glownate) |
|---|---|---|
| Method | Chemical bleaching | Lightly shape the tooth surface and bond ceramic |
| Tooth reduction | None | Approx. 0.3–0.7 mm reduction |
| Reversibility | Reversible | Irreversible |
| Indications | Yellow hue, extrinsic staining | Pronounced discoloration, shape correction, spacing (gaps) |
| Cost (based on 6 front teeth) | 300,000–800,000 KRW (approx. $220–$580) | Approx. 3,000,000–9,000,000 KRW (approx. $2,190–$6,570) |
| Longevity | 1–3 years | 10–15 years or more |
| Recovery time | None | Approx. 1–2-week adjustment period |
If your teeth are only slightly dark and the shape is fine, Teeth Whitening should be considered first; if issues like tooth shape, spacing, or angulation exist in addition to color, Laminate Veneers offer a more comprehensive solution. Complete Guide to Laminate Veneersfor a detailed comparison.
Seoul BD Dental Glownate
Seoul BD Dental’s Glownateis an in-house Laminate Veneer system that minimizes tooth reduction—down to about 0.3 mm compared with conventional laminate veneers (0.5–0.7 mm)—and is designed to preserve natural tooth texture and luster. When Teeth Whitening isn’t enough, consider this as a step-up option.
08Frequently Asked Questions
We’ve compiled the most common questions patients ask about Teeth Whitening.
Q.Will Teeth Whitening really make my teeth as white as the photos in ads?
The dazzling 'pure white' in before-and-after ads is usually from Laminate Veneers or all-ceramic restorations, or the images have been digitally retouched.
With Teeth Whitening, a naturally achievable shade is around Vita A1–B1, which is very bright for natural teeth. Because everyone’s baseline tooth color, enamel thickness, and dentin hue differ, the maximum shade you can reach varies from person to person.
At your consultation, objectively confirm your starting shade and target shade with the dentist, and set realistic expectations—this is key to a satisfying outcome.
Q.Do Dental Implants and crowns whiten, too?
No. Artificial restorations do not whiten.
Hydrogen peroxide acts only on pigment molecules in living teeth. Artificial restorations such as Zirconia or ceramic crowns on Dental Implants, Composite Resin fillings, and Laminate Veneers will not change color at all.
Therefore, before Teeth Whitening, the usual sequence is to decide the restoration shade again—to match the natural teeth after whitening. If you already have restorations and whiten to match them, only the natural teeth will lighten and the color difference can stand out, so be sure to discuss this with your dentist beforehand.
Q.Is Teeth Whitening okay during pregnancy or breastfeeding?
Not recommended.
Because there isn’t sufficient safety data on hydrogen peroxide for pregnant women, fetuses, or infants. Although direct harm has rarely been reported, the medical principle is to avoid unnecessary exposure—and because whitening is cosmetic, it’s best to postpone it.
During pregnancy, hormonal changes can make your gums more sensitive, which can increase the risk of whitening side effects. It’s safest to have treatment after breastfeeding has finished, about 6 months~1 year after delivery.
Q.Do store-bought whitening products (whitening strips, whitening pens) work?
Their effect is very limited, and the risk of side effects is high.
OTC whitening products sold at pharmacies or online contain about 1~6% hydrogen peroxide, which is far lower than the concentrations used in dental offices (15~40%). They may remove minor surface stains, but the underlying shade hardly changes.
The bigger problem is that they are **used without gum protection**, creating a risk of gum burns; if you use a generic tray that doesn’t fit your teeth, the gel can easily leak onto adjacent gums and oral mucosa. Some overseas direct-purchase products are high-concentration items without approval from the Korean Ministry of Food and Drug Safety (MFDS), and cases of gum and tooth injury have occurred.
For long-term satisfaction, it’s safest and most effective to receive a proper diagnosis at a dental clinic and be treated with a method tailored to you.
Q.What is internal whitening, and who is it for?
Internal Whitening (Walking Bleach) places a whitening agent inside a tooth that has turned gray or brown after Root Canal Treatment of a non-vital tooth.
After Root Canal Treatment, residual blood and denatured proteins inside the tooth break down over time, darkening the tooth. External whitening agents do penetrate enamel, but they rarely reach the already discolored, treated canal space. Therefore, opening a small area on the back of the tooth to place the whitening agent directly into the Root Canal Treatment space and sealing it temporarily is effective.
The whitening material is replaced over 2~3 visits, at 1~2 week intervals. It is highly effective for whitening a single tooth, but it is never applied to vital teeth.
Q.Does teeth whitening make teeth weaker?
Professionally performed whitening does not weaken enamel.
Although there were past concerns that "whitening corrodes teeth," current clinical studies report little to no clinically meaningful change in enamel microhardness or surface structure when whitening is done at appropriate concentrations and times.
However, tooth damage risk increases in the following situations: - Excessively high-concentration or prolonged whitening (unverified direct-purchase products, etc.) - Daily use over a long period (every day for 1 year or more) - Use on teeth that already have cracks or severe wear - Whitening performed without gum isolation/protection
That’s why whitening should be done after a dental evaluation, and touch-up whitening should be spaced at least 6 months apart.
Still have questions about teeth whitening?
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Columns on this topic, personally written by Dr. Seokjun Moon
We’ve compiled the questions we get most often in the clinic.