Teeth whitening is one of the most popular cosmetic dentistry treatments, providing a quick, non-invasive, and cost-effective way to improve one’s smile. Whitening (or bleaching) treatments are universally valued by men and women alike, and there are options to suit every budget, time frame, and temperament. Solutions abound, whether in the form of professional one-hour whitening sessions at a dental office or cosmetic spa, or home-use bleaching kits purchased at your local drugstore.

Almost everyone who chooses a teeth whitening solution notices a moderate to significant improvement in the brightness and whiteness of their smile. However, it is not a permanent solution to discoloration and requires maintenance or “touch-ups” to have a long-lasting effect. Know more

The FDA allows the term “bleaching” to be used only when teeth can be whitened beyond their natural colour. This only applies to products containing bleach, which is typically hydrogen peroxide or carbamide peroxide.

The term “whitening,” on the other hand, refers to the process of restoring the surface colour of a tooth by removing dirt and debris. So, technically, any product used to clean the teeth (such as toothpaste) is considered a whitener. Of course, whitening sounds more appealing than bleaching, so it is more commonly used — even when describing products containing bleach.
Before and after teeth whitening close-up of a smiling woman
When time is of the essence, the bleach of choice for in-office whitening is powerful and fast-acting hydrogen peroxide.
When bleaching teeth, hydrogen peroxide concentrations range from about 9% to 40%.

In contrast, the preferred bleach for at-home teeth whitening is the slower-acting carbamide peroxide, which degrades into hydrogen peroxide. Carbamide peroxide is roughly one-third the strength of hydrogen peroxide. This means that a 15% solution of carbamide peroxide is roughly equivalent to a 5% solution of hydrogen peroxide.

Because of our porcelain-like enamel surface, most of us start out with sparkling white teeth. Tooth enamel, which is made up of microscopic crystalline rods, is designed to protect teeth from the effects of chewing, gnashing, trauma, and acid attacks caused by sugar. However, enamel deteriorates over time, becoming more transparent and allowing the yellow colour of dentin — the tooth’s core material — to show through.

Dentin remains intact during routine chewing, while millions of microcracks form in the enamel. These cracks, as well as the spaces between the crystalline enamel rods, accumulate stains and debris over time. As a result, the teeth become dull and lacklustre over time.

Teeth whitening removes stains and debris from the teeth while leaving the enamel cracks open.Some cracks are quickly remineralized by saliva, while others are filled with organic debris.

When it comes to teeth staining, there are two types: extrinsic and intrinsic.

Extrinsic stains are those that appear on the surface of the teeth as a result of drinking dark-colored beverages, eating dark-colored foods, smoking, and normal wear and tear. Extrinsic stains on the surface are minor and can be removed with brushing and prophylactic dental cleaning. Extrinsic stains that are stubborn can be removed with more involved efforts, such as teeth whitening. If persistent extrinsic stains are not treated promptly, they can penetrate the dentin and become ingrained.Intrinsic stains are those that develop on the inside of the teeth. Intrinsic stains are caused by trauma, ageing, mineral exposure (such as tetracycline) during tooth formation, and/or excessive fluoride consumption. Previously, it was assumed that intrinsic stains were too resistant to be removed by bleaching. Cosmetic dentistry experts now believe that even deep-set intrinsic stains can be removed with supervised at-home teeth whitening that is maintained for months or even a year. If all else fails, dental veneers are an alternative cosmetic treatment for intrinsic staining.

What Causes Tooth Discoloration?
Age: Tooth colour and age have a direct correlation. Teeth darken over time due to wear and tear and stain accumulation. Whitening will most likely produce immediate and dramatic results in teenagers. When teeth begin to show a yellow cast in their twenties, whitening may require a little more effort. By the 1940s, the yellow has given way to brown, and more maintenance may be required. By the age of fifty, the teeth have absorbed a slew of stubborn stains that can be difficult (but not impossible) to remove.

Starting colour: We all have an inborn tooth colour that ranges from yellow-brownish to greenish-grey and darkens with age. In general, yellow-brown is more bleachable than green-grey.

Translucency and thinness : These are also genetic characteristics that worsen with age. While all teeth have some translucency, those that are opaque and thick have an advantage in that they appear lighter in colour, have more sparkle, and are bleachable. Teeth that are thinner and more transparent, particularly the front teeth, contain less of the pigment required for bleaching. Transparency, according to cosmetic dentists, is the only condition that cannot be corrected by any type of teeth whitening.

Consumption of red wine, coffee, tea, cola, carrots, oranges, and other deeply coloured beverages and foods causes significant staining over time. Furthermore, acidic foods like citrus fruits and vinegar contribute to enamel erosion. As a result, the surface becomes more transparent, revealing more of the yellow-colored dentin.

Smoking habits: Nicotine deposits brownish deposits on the tooth structure, causing intrinsic discoloration.

Tetracycline use during tooth formation results in dark grey or brown ribbon stains that are extremely difficult to remove. Fluorosis (discoloration marked by the appearance of faint white marks on the teeth) and associated areas of white mottling are caused by excessive fluoride consumption.

Grinding: Teeth grinding (gnashing, bruxing, etc.) can contribute to micro-cracking in the teeth and cause the biting edges to darken.

Trauma: Falls and other injuries can cause large cracks in the teeth, allowing stains and debris to accumulate.

Today, three major teeth whitening options are available. All three rely on varying peroxide concentrations and application times.

Whitening in the Office

The main advantage of in-office whitening is the significant colour change in a short period of time. This protocol calls for the careful application of a relatively high-concentration peroxide gel to the teeth by a dentist or trained technician after the gums have been protected with a paint-on rubber dam. In most cases, the peroxide remains on the teeth for several 15 to 20 minute intervals totaling an hour (at most). Those with particularly stubborn staining may be advised to return for one or more additional bleaching sessions, or may be asked to continue with a home-use system.

Take-Home Kits Prepared by a Professional

Many dentists believe that professionally dispensed take-home whitening kits will produce the best long-term results. Take-home kits include an easy-to-apply lower-concentration peroxide gel that can be left on the teeth for an hour or more (sometimes overnight). The lower the percentage of peroxide, the longer it can be used safely.

Over-the-Counter (OTC) Items

Over-the-counter bleaching is the cheapest and most convenient option for teeth whitening, involving the use of a store-bought whitening kit containing a bleaching gel with a lower concentration than professionally dispensed take-home whiteners. The gel is applied to the teeth using trays, strips, or paint-on applicators that are one-size-fits-all. Unlike custom trays, which can whiten the entire smile, this may only whiten a few of the front teeth in many cases.

When procedures are followed exactly, teeth whitening treatments are considered safe. However, there are some risks to bleaching that you should be aware of:

Bleaching can temporarily increase your sensitivity to temperature, pressure, and touch. This is most likely to happen during in-office whitening, when a higher concentration of bleach is used. Some people get sudden shooting pains (“zingers”) down the middle of their front teeth. Individuals with gum recession, significant cracks in their teeth, or leakage caused by faulty restorations are most vulnerable to whitening sensitivity. It has also been reported that redheads, even those with no other risk factors, are more likely to experience tooth sensitivity and zingers. Whitening sensitivity lasts only a day or two.

Gum irritation: More than half of those who use peroxide whiteners experience gum irritation as a result of the bleach concentration or contact with the trays. Such irritation can last for several days after bleaching is stopped or the peroxide concentration is reduced.
Restorations such as bonding, dental crowns, or veneers are not affected by bleach and thus retain their original colour while the surrounding teeth are whitened. This results in what is commonly referred to as “technicolour teeth.”

Keeping Your Results
Dentists are likely to recommend the following to extend the life of newly whitened teeth:

At-home follow-up or maintenance whitening can be done right away or as infrequently as once a year.
After whitening, avoid dark-colored foods and beverages for at least a week.
When possible, sip dark-colored beverages through a straw.
Brushing and flossing after meals and at bedtime are examples of good oral hygiene.