What is Teeth Whitening – At-Home & In-Office Methods + Precautions

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Human beings usually have 32 permanent teeth made from a hard bone-like substance.

Each tooth contains the white visible crown and the root that anchors our teeth to the bones.

There are four tissues – enamel, dentin, cementum, and pulp.

The enamel is the outer visible tissue that comprises microscopic crystalline rods that start off a sparkling white. These get worn out over the years due to the food we eat and trauma such as chewing and gnashing.

This causes cracks and gaps to appear in the enamel and they get filled with debris and stains and begin to appear dull and lackluster.

It also exposes the lower dentin layer and this is usually what gives our teeth the yellowish, off-white or grayish color.

Our genes can determine the color of our teeth.

Other reasons for teeth to become discolored include – poor oral hygiene, congenital or inherited diseases, and certain drugs like antibiotic tetracycline, environmental factors, excess fluoride use or neonatal jaundice, eating and drinking dark-colored foods.

Smokers and older age people are also likely to have discolored teeth.

Depending on the type of stains, there are 2 main causes for discoloration – extrinsic or surface stains and intrinsic stains.

What is Teeth Whitening

We cannot avoid discoloration of our teeth.

However, there are many cosmetic dental procedures which are available that can remove these stains and make our teeth several shades whiter.

This is called teeth whitening and it refers to the process of bleaching our teeth using one or more methods. This can remove stains but will not make our teeth a brilliant shade of white.

There are many teeth whitening products available both from professionals and whitening kits that can be used at home.

Methods of teeth whitening can be both in-office and at-home procedures.

In-office or Professional teeth whitening

In-office or Professional teeth whitening requires several visits to the dentist.

The dentist will first examine you to check for any dental problem like cavities, gum disease or restorative work done. If you are eligible for teeth whitening, the dentist will advise you about the most suitable method for you.

This could be:

  • Laser teeth whitening: This is also called chair-side bleaching. For this, the dentist will first place a protective rubber shield over your gums to prevent damage to soft tissues. He will then apply a bleaching gel on your teeth and a special laser or LED white light will be passed over the teeth. This activates the whitening agent and the process of whitening begins. The number of sittings depends on the extent of staining. Each session can last 30-60 minutes.   Usually, hydrogen peroxide or carbamide peroxide of 15-35% concentration will be used during laser therapy.
  • Custom made mouth guards or mouth trays: The dentist can give you a custom-made tray and whitening gel that can be used at home. For this, he or she will take an impression of your teeth and prepare a mouth guard. Along with this, a whitening gel (usually carbamide peroxide gel of 10-20% concentration) will be given. You will be given specific instructions on how to use this mouth guard. Usually, it can be used for 2 hours or even longer if the gel concentrations are low and for 2-6 weeks.

The benefits of professional teeth whitening are that it safe and effective since it is monitored by the dentist, it can make teeth even 12-15 shades whiter and the dentist gets to assess your teeth and treat you for any dental problems before the whitening procedure is undertaken.

The main issue with professional teeth whitening is that it is expensive – costing $500 or more for each sitting.

A combination of both the above procedures could cost even $1000 or more.

So, before opting for this, first, weigh the pros and cons and go to a dentist with a good reputation and who has good equipment to deliver the best results.

At-home teeth whitening

Revealed - Most Popular Methods for Teeth Whitening

Home teeth whitening products can be supplied by the dentist or purchased at drug stores, online retail stores etc.

These will be cheaper than professional whitening methods, they are simple to use and can even be taken to work or used when traveling.

There are many products available like trays, strips, gels, whitening trays, whitening toothpaste, whitening pens etc.

Whitening trays

While custom-made whitening trays can be supplied by the dentist, these are also available as OTC products.

These trays will come in a standard size that fits most people. It can be fitted directly on your teeth.

The tray will come with pre-filled whitening gel or sometimes the gel will be provided in a tube or syringe and can be dispensed on the tray.

The gel will usually be a 10-22% concentration of hydrogen peroxide or carbamide peroxide. The tray can be used to whiten both upper and lower teeth.

Whitening trays may be used for at least 2 hours a day or overnight for 4 weeks or longer – depending on the concentration of gel and the level of discoloration.

OTC mouth trays are cheaper than custom made ones. However, the latter can be used multiple times and you need to only purchase fresh bleaching gel.

Teeth Whitening Gel

Teeth whitening gel can be used directly or along with an aid like a strip or tray. When applied directly on the teeth, you use a small brush and spread the gel directly.

These gels usually made from hydrogen peroxide or carbamide peroxide with a 10-22% concentration can be applied twice daily for 14 days.

Teeth Whitening Strips

These OTC teeth whitening products are extremely popular. They have a special coating of hydrogen or carbamide peroxide whitening gel.

The strips are usually made from flexible, thin, transparent membranes made from polyethylene.  You simply need to take each strip and place them on your teeth.

They adhere very well and are convenient to use. Being of a transparent material, these strips can even be used when outdoors – traveling, shopping, work etc.

Store-bought whitening strips may contain less peroxide than the one supplied by the dentist.   Whitening strips can be used twice daily for 2 weeks. Leave it on for 30 minutes each time.

The results can be seen after a few days and may last for at least 4 months.

Teeth Whitening Toothpaste

These work like any other toothpaste except that they contain mild abrasives like silica that can remove surface stains that get deposited on teeth enamel.

It can also help maintain the brightness of your teeth. Some whitening toothpastes may contain small amounts of hydrogen peroxide and this will improve whitening effects.  ,

Teeth Whitening Rinse

These contain hydrogen peroxide and can reduce gum disease, dental plaque and get rid of surface stains. It can be used twice a day for about 60 seconds each.

Teeth Whitening Pens

This comprises a pen that dispenses a bleaching agent – hydrogen peroxide. The pen contains a tiny brush or sponge that makes application very easy.

You simply need to squeeze the pen and spread the gel evenly on the teeth. It is also easy to reach all your teeth and even use it to paint one tooth at a time if needed.

Simple Home Remedy

This is an easy and simple way to whiten teeth at home without spending on home whitening kits. Just mix a little baking soda and juice of one lemon in a bowl.

Wipe out excess saliva from teeth and mouth using some cotton.

Immediately dip a cotton swab in it and brush lightly on your teeth. Brush and rinse thoroughly after one minute. Do not keep this more than a minute.

Natural Teeth Whitening Ways

For those who do not wish to use chemicals on their teeth, there are many natural teeth whitening products available in your own kitchen.

Strawberries: They contain both vitamin C and astringent that effectively remove surface stains and clear plaque.

Apples: Chewing on a crunchy apple helps to scrub surface stains and get rid of bacteria and excess food caught between teeth.

Malic acid which is a chemical that can dissolve stains and is used in many teeth whitening products is found naturally in apples.

Raisins: Eating a handful of raisins induces production of saliva. This increased saliva production helps to rinse out plaque and food debris.

The benefits of home teeth whitening is that it is convenient for those who live very busy professional lives and who feel that a visit to the dentist for periodic teeth whitening can be time-consuming.

It is also simple to use.

Home teeth whitening is also recommended by the dentist as an adjunct treatment for professional teeth whitening.

This helps to achieve long-term results.

Most home whitening systems can even be used when traveling or at work. At-home OTC kits are reasonably priced when compared to those supplied by a dentist, ranging in cost from $4-$100 making them easily affordable.

There are a few issues with home teeth whitening kits.

If the mouth guard does not fit your teeth properly it could cause seepage of the bleach into your gums and teeth and cause sensitivity and blistering.

Always seek the advice of a dentist who will recommend the right product. OTC teeth whitening kits if they are not of a good brand may not contain sufficient bleaching agent to be effective.

Before purchasing an OTC product, you can also ask a friend or read online reviews before doing so.

Get a product that allows you to adjust the mouth guard so that it fits your teeth better.

If you experience any pain, sensitivity or changes to the gum color, stop using the product at once and seek medical help.

Possible Side Effects of Teeth Whitening

Here are some possible side effects. Note, they generally do not occur but it is best to keep them in mind along with precautions to ensure safety.

Teeth Sensitivity

This is the most common side effect of teeth whitening.

Sensitivity could occur during and after the bleaching process.

When teeth are whitened, the dentin layer could get exposed. This comes in contact with the bleaching gel and causes the sensitivity.

If you already have sensitive teeth, it would be best to consult the dentist who will give you the various options available that will lessen sensitivity. The dentist will also recommend suitable products that can reduce sensitivity.

Those with cracked teeth or with receding gums are more at risk of experiencing sensitivity. Some people can experience unbearable shooting pain called ‘zingers’.

Potassium nitrate toothpaste can alleviate some of these symptoms.

Sometimes, if the teeth whitening tray does not fit properly, some of the gel can seep through and affect the soft tissues. This can be avoided by using custom-made mouth trays.

You can even try to use the trays for a shorter period to reduce sensitivity.

Irritation of Soft Tissue

Very often, soft tissue in the mouth like the gums gets exposed to the chemicals which make up the whitening gel.

This causes soft tissue irritation like inflammation and is called a chemical burn.

Initial exposure to carbamide or hydrogen peroxide will cause the gums to turn white.

Prolonged exposure to high concentrations can cause redness and inflammation of gum and other soft tissue. In some extreme cases, it could also cause bleeding and pain.

Other reactions

Over expectation can also cause some undesirable results. For example, if teeth are heavily stained or if there is internal tooth discoloration, regular teeth whitening may not return them to their original whiteness.

If you expect your teeth to get a brilliant shade of white and start whitening them too often, this could, in fact, cause the opposite effect and turn your teeth into a translucent or gray shade rather than the creamy white most people desire.

Sometimes, you may end up with ‘Technicolor teeth’.

This occurs if you have a combination of natural and restored teeth.

Then when you whiten teeth, while the veneers and bonds remain the same, the surrounding teeth get whitened and then your teeth end up in different shades.

Causes of Such Side Effects

While the above are some of the side effects of teeth whitening, knowing the causes could help mitigate them to a certain extent at least.

Often high concentrations of carbamide or hydrogen peroxide will cause sensitivity and irritation. These days, bleaching gels come well buffered.

This reduces the sensitivity levels to a great extent.

Sometimes, if the product is not good or leaving the bleaching agent on your teeth for longer than required can also cause side effects.

Hence, choose clinically proven products from good brands, follow instructions carefully when using teeth whitening products at home and consult your dentist when choosing to use any home teeth whitening product.

Tips to Reduce These Side Effects

Your dentist can provide you with products that contain fluoride that can re-mineralize your teeth and reduce sensitivity.

You can use this to brush your teeth or even wear it on the tray and apply it to your teeth before and after teeth whitening.

Sometimes, simply stopping the process for a few days to allow teeth to get used to the whitening gel can also help.

Not everyone can undergo teeth whitening due to the side effects. When you consult a dentist, he will tell you if you can undergo the procedure or not.

Pregnant women, children under 16 years of age, anyone who suffers from allergies, has sensitive teeth, worn enamel, gum disease, has exposed roots or cavities, crowns, fillings or other restorative work may not be able to undergo teeth whitening.

However, you need not despair for there are other alternatives to whitening teeth. You can have crowns, caps or fillings done which will be tooth colored. You can also have veneers and bonding done.

These are meant for chipped, broken or extremely stained teeth.

Veneers are porcelain coverings that are fitted on the teeth and bonding is a procedure that uses composite resin to fill gaps or restore and reshape broken teeth.

Teeth whitening using non-chemical products such as an electric toothbrush will not cause any side effects.

The proliferation of numerous over-the-counter teeth whitening products which do not require a prescription means that sometimes people misuse or overuse them.

A little common sense when using such products can prevent many of the unwanted side effects of teeth whitening.


There are several teeth whitening methods available including at-home and in-office. Both have their own pros and cons and you must decide the one best suited to your needs.

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