Introduction

Hi guys,

Here's the introduction. It is two and a quarter pages including the heading and footnotes. I lost some formatting when I pasted it in here.
I tried to mention our previous triclosan lab, since that is one of the requirements. Also, I referenced two scientific papers (three are required).

Here is a description of what an introduction should include:
"The purpose of this section is to state the objective of your study. You will present relevant background information in order to familiarize the reader with your research topic. For example, background information on how enzymes catalyze reactions, and why they are important in organisms, would be appropriate in your enzyme report. Your hypothesis should be clearly stated here, along with a well supported, scientifically valid rationale for the hypothesis. Your hypothesis should be no more than one or two sentences. Your hypothesis can be followed by a set of predictions based on your hypothesis. Finally, discuss the variables you will measure in order to test your hypothesis."

Yay! please edit!

Sarah


Sarah, Beatrice, Deborah, Lisa, Victoria
Advanced Biology Period 1
May 19, 2007


Effectiveness of Mouthwashes in the Inhibition of the Growth of E. coli and Oral Flora

After inducing resistance to triclosan in E. coli, our group was interested in testing the efficacy of a product with similar anti-bacterial properties. We seized on mouthwash as a common household item whose effectiveness as an anti-bacterial agent is very important to consumers.
The primary purpose of most mouthwashes is to kill oral bacteria in order to prevent bad breath and/or fight plaque and gingivitis[1]. The active ingredients in mouthwashes vary, from thymol[2] (a plant-derived antiseptic[3]) and sodium benzoate[4] to witch hazel and vitamin C[5]. In order to conduct the most informative assay of the effectiveness of mouthwash, we chose to compare several brands which vary in both their advertising claims and their active ingredients. The products chosen were Listerine Antiseptic Original, Scope Original Mint, and Tom’s of Maine Natural Cleansing Mouthwash in Spearmint. The active ingredients of Listerine Original include thymol, methyl salicylate, menthol, and eucalyptol. Their stated purpose is fighting plaque and gingivitis. Thymol is an antiseptic while menthol[6], eucalyptol[7], and methyl salicylate[8] (oil of wintergreen) are flavoring agents. Listerine also contains denatured alcohol (26.9%) “as a solubilizer for flavors and active ingredients”[9], benzoic acid, poloxamer 407, sodium benzoate, and caramel[10]. The company claims that Listerine Original “kills germs that cause plaque, gingivitis and bad breath” and “provides 24-hour protection against plaque and gingivitis germs when used morning and night”­10.

Tom’s of Maine contains witch hazel and ascorbic acid (Vitamin C) for an “astringent feel”, aloe vera for a “soothing feel”; and glycerin, spearmint oil, and menthol for flavor­­5. Poloxamer 335 is used for dispersion of flavorings, and water is included to improve the consistency of the product. Advertising for this mouthwash emphasizes its lack of alcohol5.

The ingredients of Scope Original Mint include water, alcohol (15 WT%), glycerin, polysorbate 80, flavor, sodium saccharin, sodium benzoate, cetylpyridinium chloride, benzoic acid, blue 1, and yellow 54. Scope is classified by its parent company as “a cosmetic mouthwash” designed to kill the bacteria that cause bad breath[11].

We hypothesized that Listerine would be most effective in preventing the growth of bacteria, that Scope would have some preventative effect, but not as great as that of Listerine, and that Tom’s of Maine would not prevent bacterial growth. Our rationale for this hypothesis was that if Listerine kills 99.9% of bacteria on contact, as the company claims, it will prevent the growth of bacteria on a plate. Also, independent clinical studies have shown that Listerine does significantly reduce plaque and gingivitis after six months of use[12]. We concluded that Listerine would work better than Scope in preventing bacterial growth because Scope’s advertising does not claim to kill 99.9% of bacteria. In addition, Listerine has the American Dental Association (ADA) seal of approval for preventing plaque and gingivitis[13]. Scope does not have this accreditation[14]. However, because Scope does contain anti-bacterial agents, we decided that it should have some ability to prevent the growth of bacteria. Conversely, the lack of an antimicrobial ingredient in Tom’s of Maine’s led us to hypothesize that it would not inhibit bacterial growth.

A variable used to test this hypothesis included the concentration of bacteria used on the plates to which the mouthwashes were applied (1:10, 1:100, 1:1000, and 1:10,000). A second variable was the testing of the mouthwashes’ effectiveness against both E. coli and an oral culture. We hypothesized that the mouthwashes would be more effective against oral bacteria than E.coli because oral bacteria are the organisms they were designed to kill and there should be little if any E. coli in the mouth.

[1] “Oral Health Care Products: Mouthrinses”
[2] http://www.pfizerch.com/product.aspx?id=428
[3] Shapiro and Guggenheim
[4] http://www.pg.com/content/pdf/01_about_pg/msds/health_care/oral_care/Scope_Liquids.pdf
[5] http://www.tomsofmaine.com/toms/product.asp?dept%5Fid=350&pf%5Fid=MW
[6] http://en.wikipedia.org/wiki/Menthol
[7] http://en.wikipedia.org/wiki/Eucalyptol
[8] http://www.chemistrystore.com/methyl_salicylate.htm
[9] http://www.pfizerch.com/faq.aspx?brand=298#FAQ935
[10] Listerine.com
[11]http://pg.custhelp.com/cgi-bin/pg.cfg/php/enduser/std_adp.php?p_faqid=5592&p_created=1114095268&p_sid=dV3e5gCi&p_accessibility=0&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9NTgmcF9wcm9kcz00JnBfY2F0cz0wJnBfcHY9MS40JnBfY3Y9JnBfcGFnZT01&p_li=&p_topview=1
[12]http://jada.ada.org/cgi/content/full/132/5/670?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=1&andorexacttitle=and&andorexacttitleabs=and&fulltext=listerine&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT
[13] http://www.ada.org/ada/seal/pro-com1.asp?company=Johnson%20%5e%20Johnson%20Consumer%20%5e%20Personal%20Products%20Worldwide
[14] http://www.ada.org/ada/seal/sealsrch.asp