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Does Whitening Toothpaste Really Work?

 

Julie Won

October 23, 2007

 

INTRODUCTION:

          What is the craze?? Today, grocery store shelves are stacked full of teeth whitening toothpastes and kits. It seems as though everyone wants that beautiful, pearly white smile and many people will do whatever it takes to get it. These days, ads and especially ¡°popular" magazines suggest that tooth color is a significant factor in the attractiveness of a smile. An attractive smile plays a major role in the overall perception of physical attractiveness¡± (Kihn, 2007). Studies show that our society places a strong importance on the connection between attractiveness and success. Surprisingly, there were people ¡°whitening their teeth even in the pharaoh¡¯s ancient Egypt¡± (http://www.brilliantsmile.se/tandblekning/tand-blekning_en.asp). Although there¡¯s an increase in those getting their teeth professionally whitened at the dentists¡¯ office, there are still many who prefer giving whitening toothpastes a chance and thus, wish to know if these toothpastes really whiten their teeth (http://www.essortment.com/lifestyle/beautywhitening_slgj.htm).

Does whitening toothpaste really work?

  

 

HOW DO TEETH GET YELLOW, ANYWAY?

        The yellow discoloration in our teeth is natural and inevitable. These stains inside the tooth are called intrinsic stains.  As we age, the innermost layer of our tooth, called dentin, changes yellow in color. In her article regarding vital tooth whitening, Dr. Patricia Kihn says that ¡°discoloration results from the aging process. As teeth age, more secondary dentin is formed and the more translucent enamel layer thins¡± (Kihn, 2007).  

 http://www.colgate.com/app/Colgate/US/OC/Information/OralHealthBasics/CommonConcerns/Cavities/IllustrationsHowAToothDecays.cvsp

 

Furthermore, it is proven that exposure to too much fluoride also causes the inner dentin layer to change color. However, each tooth can become discolored on the outer layer as well. The enamel is made up of pores that can hold stains; this is why products such as coffee, red wine, iron salts, certain medications, and tobacco stain our teeth to a greater degree than most other foods. Not only does the enamel hold stains, but there is also a sticky coating on the outside of your tooth that picks up stains. Since tooth whitening toothpaste is most effective on surface stains, its result is temporary and it does not penetrate the discoloration of the inner-most layer of the tooth (http://www.goaskalice.columbia.edu/0680.html).

http://nutrizone.com/img/bef-aft.jpg

 

WHAT ARE THE KEY ¡®WHITENING¡¯ INGREDIENTS IN WHITENING TOOTHPASTES?

A)    Carbamide Peroxide – This is the chemical that bleaches your teeth with each usage.

B)    Abrasives – These can include alumina, silica, calcium carbonate and dicalcium phosphate which help break up the stains off the surfaces of the teeth.

C)   Detergents (sodium lauryl sulfate) – This chemical is basically like soap which foams and cleans the outer layer of the teeth.

D)   Polyvinylpyrrolidone (PVP) – This is a protective ingredient that keeps stains away from the tooth surface.

E)    Others – These include enzymes such as papain, triclosan, citric acid, sodium tripolyphosphate

(http://www.choice.com.au/viewArticle.aspx?id=104583&catId=100563&tid=100008&p=4&title=Test%3a+Whitening+toothpaste)

 

It¡¯s important to note that there are a few whitening toothpastes which have a sole purpose to ONLY whiten teeth; most whitening toothpastes are meant to clean teeth, prevent cavities, AND whiten. Hence, most whitening toothpastes only contain a small concentration of the whitening chemical because they also contain protective tooth decay ingredients such as fluoride (http://www.goaskalice.columbia.edu/0680.html).

 

**Attention** -- Not all whitening toothpastes contain peroxides; abrasives are the main source of ¡°scouring¡± off those surface stains.  For whitening toothpastes that do contain peroxides, the chemical barely has time to seep through the surface of the tooth after the abrasives have diminished most of the stains. Thus, to see whitening results using whitening toothpaste, one must be consistently brushing their teeth over an approximate 4-week period (http://www.dental-picture-show.com/teeth-whitening/a7-best-tooth-whitening-toothpaste.html)

 

 

What¡¯s the history behind teeth whitening?

Have you ever wondered where the idea of teeth whitening came from?  The beginnings of teeth whitening actually began almost a century ago by accident. In 1916, T.C. Adams found that hypochloric acid could treat dental fluorosis, which is a white mottling on the teeth due to excessive intake of fluoride either from certain toothpastes or excessive amounts of fluorinated water.

       

http://www.nofluoride.com/tooth.gif                       http://www2.next.ne.jp/~sirayuki/img/mottled%20t.jpg

 

Later in 1937, J.W. Ames reported a mixture of two different chemicals, hydrogen peroxide and ethyl ether, plus heat, to treat mottled enamel. In 1966, hydrochloric acid and hydrogen peroxide were proven to treat brown stains on mottled teeth. For over 50 years, treating mottled teeth, an extrinsic stain, was the ultimate goal. Beginning in 1970, however, researchers found a method for treating stained dentin, an INTRINSIC STAIN, in cystic fibrosis patients using hydrogen peroxide. There was now evidence that ¡°chemical penetration of hydrogen peroxide to the dentin¡± could whiten teeth. In an experiment to improve gingival infection, a 10% carbamide peroxide solution was implemented; an important observation was whitened teeth which provided for further studies in the correlation between peroxides and tooth whitening. Soon enough, night guard bleaching techniques and bleaching in dental offices became popular (Kihn, 2007).

           

Is there scientific evidence that whitening toothpastes work?

        In a 2004 study, researchers did an experiment to ¡°determine the effect of natural calcium carbonate toothpaste containing Perlite and microgranules (Whitening toothpaste) on extrinsic tooth stain compared to a standard commercial toothpaste formulation with precipitated calcium carbonate (PCC) as abrasive and a commercial toothpaste with dicalcium phophate dihydrate (DCPD) as abrasive.¡± The experiment method included a double blind, parallel group design study using 600 people with extrinsic stains. The study consisted of four weeks, each person brushing their teeth twice a day with the allotted toothpaste which was given to them. According to the t-test results and ANCOVA, whitening toothpaste was shown to be much more superior and effective in removing teeth stains than the other two products (Matheson, et al., 2004).

          In a review article of the 2006 International Dental Journal, researcher Andrew Joiner reiterates the validity of the Matheson experimental results through a separate experiment saying that whitening toothpaste ¡°has been shown to be more effective in removing naturally occurring extrinsic tooth stain than a silica non-whitening control toothpaste after two weeks of twice daily brushing in a parallel group, double-blind clinical study using 152 adult volunteers. In addition, the enhanced whitening effect did not give a clinically relevant level of wear to enamel or a significant increase in dentine wear compared to marketed non-whitening toothpaste formulations, as shown by using an in situ type model with ex vivo brushing¡± (Joiner A, 2006).

          However, some experiments with whitening toothpaste proved to be a little less than successful. In an experiment to compare a test whitening toothpaste versus a conventional fluoride paste, the results did not show a significant difference. The experimental method used, however, lasted only one week and the 24 subjects performed a forced rinse method through repeated chlorhexidine/tea rinses 8 times each day of the week. The results stated: ¡°The study showed no difference in the ability of the test whitening toothpaste, control toothpaste and water control at inhibiting stain... The difference was however in favor of the test product which approached a conventional level of significance (P = 0.089)... This study has suggested that the test product may have some advantage over the conventional paste at removing stain but the magnitude of difference would appear to be small and of little clinical relevance¡± (Moran J, et al., 2005).

          There has also been a study comparing regular Colgate toothpaste (control group) and Crest white strips (test group). The Crest white strips contained 6% hydrogen peroxide and were worn by the subjects for 30 minutes, twice a day.

Results showed that the test group, the Crest white strips, showed a significant difference in tooth color versus the regular Colgate toothpaste over a two week period (Luo W, et al, 2007). This indicates that Crest White strips has a higher level of active ingredient, hydrogen peroxide, therefore, it is a stronger whitening agent than whitening toothpaste. Further experimentation proves that this is the case. In an experiment testing the effectiveness of various over-the-counter dental products, whitening strips proved to be the most effective in teeth whitening due to its high concentration of hydrogen peroxide.  The whitening strips contained 5.5%-6.5% hydrogen peroxide while the whitening gel–in-tray method contained 10% carbamide peroxide, the main bleaching ingredient in whitening toothpastes (Hasson, H, et al., 2006). 10% carbamide peroxide is equal to 3.6% hydrogen peroxide; this shows how much more HP is used in whitening strips (Kihn P, 2007). This high concentration of hydrogen peroxide, however, resulted in a number of tooth sensitivity complaints (Hasson H, et al, 2006).

 

Does whitening toothpaste really work?

 

        Yes! Indeed, it takes time and consistency in brushing your teeth twice a day to  

see distinguishing results, but it definitely does its job in temporarily breaking up stains

from the surfaces of your teeth. If you want to see significant and noticeable results, a bleaching treatment from your dentist will probably be the best option. Listed below are a few quotes from the World Wide Web:

 

-- ¡°It's impossible for a whitening toothpaste that is on the teeth usually for a maximum of one minute, to soak into the teeth and perform that kind of bleaching. The best you can hope for is to get rid of all the surface stains.¡±

http://www.mynewsmile.com/whitening_toothpaste.htm

 

--¡±It is true that whitening toothpastes do lighten your teeth, but the effect might not be as much as you hope. In fact the concentration of carbamide peroxide in such whitening toothpastes is so little that you can not expect them to do much for betterment of appearance of your teeth. However, they are a great way to preserve your whiter smile which you have acquired from dental bleaching.¡±

http://articles.ruchie.com/computers/teeth-whitening-toothpaste-does-it-work.html     

 

 

                              

 

Top 10 facts about teeth whitening

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References

 

Luo W, Westland B, Brunton P, Ellwood R, Pretty I, Mohan N. (2007). Comparison of the ability of different color indices to assess changes in tooth whiteness. Journal of Dentistry, 35(2), 109-116.

 

Hasson H, Ismail AI, Neiva G. (2006). Home-based chemically-induced whitening of teeth in adults. Cochrane Database of Systematic Reviews, (4).

 

Joiner A. (2006). Review of the extrinsic stain removal and enamel/dentine abrasion by a calcium carbonate and perlite containing whitening toothpaste. International Dental Journal, 56(4), 175-180.

 

Kihn, Patricia. (2007). Vital Tooth Whitening. Dental Clinics of North America, 51(2), 319-331.

 

Matheson JR, Cox TF, Baylor N, Joiner A, Patil R, Ketkar V, Bijlani NS. (2004). Effect of toothpaste with natural calcium carbonate/perlite on extrinsic tooth stain. International Dental Journal, 54 (5), 321-325.

 

Moran J, Claydon NC, Addy M, Newcombe R. (2005). Clinical studies to determine the effectiveness of a whitening toothpaste at reducing stain. International Journal of Dental Hygiene, 3(1), 25-30.

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