When I started my practice, the first thing I bought was a dental shade guide. Shades from D4 to A1 are found here. We use this routinely to determine the shafe of a particular tooth to be fabricated as a crown. This is when most patients see their shades and ask,"Can I better this shade". My answer to them is always, "yes, you can but I will not force you". I feel bleaching of teeth or whitening is a very personal choice. One that a dentist should not force on the patients and one that patients should not have to undergo unless they want to. Whitening, be it of teeth or skin should not inculcate a negative personal image. People in the US tend to ask their doctors for a smile so white that in the dental fraternity, we call it toilet-bowl white. That's the effect of Hollywood and Pop culture, I guess.
Having said that, let me briefly tell you about whitening of teeth or bleaching as we call it. Bleaching is done for teeth which are discoloured. Discolouration of teeth happens due to various reasons like excess fluoride in water (people from Rajasthan/Kutch have this problem), age, tetracycline medication in pregnancy or infancy, discolouration due to red wine, tobacco chewing or smoking and vibrantly coloured spices. Discolouration of a single tooth may also occur in cases of necrosis of the pulp tissue (i.e destruction of the pulp tissue due to trauma or decay). Unclean teeth also look darker due to the tartar deposits on your teeth.
To treat various types of discolorations, we use bleaching agents. But bleaching agents will not work on fillings or crowns, so an evaluation by a dentist is a must. The active ingredient in these is primarily hydrogen peroxide or carbamide peroxide. Hydrogen peroxide is a powerful oxidizer. This oxidizes the various colouring agents on the tooth surface and make the teeth whiter. But hydrogen peroxide is also very caustic and can cause burns of the soft tissue if used incorrectly or at home. Hence hydrogen peroxide based bleaching agents are reserved for use in dental office under the supervision of the dentist. These are available at strengths of 30-40% depending on the brand. Some of these are light-activated. The dentist applies these gels to the patient's teeth in cycles of 10-15 minutes each. The gums are protected by using a light-cured gel to block them out. Typically 3 cycles are recommended for a good result. I have personally used the ZOOM! system (discus dental) on my patients hundreds of times and the results are amazing. You typically get a jump of about 8 shades by using in-office bleaches. Hence, it is recommended for patients on the go and who want quick results. There is a mild sensitivity in a few patients but nothing that doesn't go away in a day or two. Also the shade tends to slightly go down a notch as the teeth, when bleached, get dehydrated. The shade stabilises over a period of 72 hours as the teeth rehydrate. We tell the patients to avoid coloured food during this period of 72 hours.
Carbamide peroxide on the other hand has only one-third the strength of hydrogen peroxide and hence is safe for at-home use. The strength of the product varies from 10-30% carbamide peroxide (3-10% hydrogen peroxide). We make an impression of the patient's upper and lower teeth. A customised soft acrylic tray is fabricated which is used by the patient in the comfort of his home. The tray is half-filled with the bleaching gel and snapped onto the teeth and kept in place for 2-6 hours, depending on the product used. The lower the strength of the product, the higher is time to keep the tray in mouth. But since the gel is very low in strength, it needs to be used for 5-10 days till a desired shade is achieved.
Some over the counter bleaching products are available but being a dentist I doubt its safety as patients wouldn't know when to stop using them. Same applies to home remedies like using soda bicarb and lime juice. One easy thing that you can do sometimes is rub crushed strawberries on your teeth. The malic acid present in it acts as a bleaching agent.
To treat various types of discolorations, we use bleaching agents. But bleaching agents will not work on fillings or crowns, so an evaluation by a dentist is a must. The active ingredient in these is primarily hydrogen peroxide or carbamide peroxide. Hydrogen peroxide is a powerful oxidizer. This oxidizes the various colouring agents on the tooth surface and make the teeth whiter. But hydrogen peroxide is also very caustic and can cause burns of the soft tissue if used incorrectly or at home. Hence hydrogen peroxide based bleaching agents are reserved for use in dental office under the supervision of the dentist. These are available at strengths of 30-40% depending on the brand. Some of these are light-activated. The dentist applies these gels to the patient's teeth in cycles of 10-15 minutes each. The gums are protected by using a light-cured gel to block them out. Typically 3 cycles are recommended for a good result. I have personally used the ZOOM! system (discus dental) on my patients hundreds of times and the results are amazing. You typically get a jump of about 8 shades by using in-office bleaches. Hence, it is recommended for patients on the go and who want quick results. There is a mild sensitivity in a few patients but nothing that doesn't go away in a day or two. Also the shade tends to slightly go down a notch as the teeth, when bleached, get dehydrated. The shade stabilises over a period of 72 hours as the teeth rehydrate. We tell the patients to avoid coloured food during this period of 72 hours.
Carbamide peroxide on the other hand has only one-third the strength of hydrogen peroxide and hence is safe for at-home use. The strength of the product varies from 10-30% carbamide peroxide (3-10% hydrogen peroxide). We make an impression of the patient's upper and lower teeth. A customised soft acrylic tray is fabricated which is used by the patient in the comfort of his home. The tray is half-filled with the bleaching gel and snapped onto the teeth and kept in place for 2-6 hours, depending on the product used. The lower the strength of the product, the higher is time to keep the tray in mouth. But since the gel is very low in strength, it needs to be used for 5-10 days till a desired shade is achieved.
Some over the counter bleaching products are available but being a dentist I doubt its safety as patients wouldn't know when to stop using them. Same applies to home remedies like using soda bicarb and lime juice. One easy thing that you can do sometimes is rub crushed strawberries on your teeth. The malic acid present in it acts as a bleaching agent.
Tooth bleaching is one of the most conservative and cost-effective dental treatments to improve or enhance a person’s smile. However, tooth bleaching is not risk-free and tooth bleaching is best performed under professional supervision and following a pre-treatment dental examination and diagnosis. In my next post I will talk about another fascinating subject, Smile Design. Till then, my beauties, keep smiling.
Dr. Rasika
Dr. Rasika
Additional reads:
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| Various shades guides |
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| ZOOM! Bleach and its use |
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| Customised acrylic trays |
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| Dentist-dispensed bleaching gel used with the acrylic trays |
