May, 2011

Triclosan – A Double Edged Sword

Ajay Kumar (BDS)

Lecturer

Pedodontia department

Narsinhbhai Patel Dental College and Hospital

Visnagar – 384 315 (North Gujarat)

India.

 

Vidhi Thaker (MSc)

Lecturer

Department of Pharmacology

Narsinhbhai Patel Dental College and Hospital

Visnagar – 384 315 (North Gujarat)

India

 

Kamlesh Singh (MDS)

Senior Lecturer,

Department of Periodontia

Narsinhbhai Patel Dental College and Hospital

Visnagar – 384 315 (North Gujarat)

 

Corresponding Author:

Ajay Kumar (BDS)

Lecturer

Pedodontia department

Narsinhbhai Patel Dental College and Hospital

Visnagar – 384 315 (North Gujarat)

India

Phone No: + 91 2765 222 271

E-mail: drajaykam@gmail.com

 

Abstract:

Triclosan, a chemical well known for it’s antibacterial and antifungal properties, is available in various household and dental products. However, the safety of triclosan has been questioned in regard to environmental and human health. While the companies that manufacture products containing this chemical claim that it is safe, the United States Environmental Protection Agency (EPA) has registered it as a pesticide. The chemical formulation and molecular structure of this compound are similar to some of the most toxic chemicals on earth, relating it to dioxins. The EPA gives triclosan high scores both as a human health risk and as an environmental risk. Recently it has been proved to be a carcinogen, allergen, endocrine disrupter, and an agent that can cause fetal brain hypoxia.  Employing a strong antibiotic agent such as triclosan for everyday use is of questionable value.

This article provides insight into triclosan and its prescriptions/uses in dental treatment.

Keywords: Triclosan, fetal brain injury, toxicity.

 

Introduction:

Triclosan is a chemical that was developed nearly 30 years ago.  It was first introduced into the Health Care Services in 1972 and since then, it is extensively used in deodorants, toothpastes, shaving creams, mouth washes, cleaning products, and is infused in an increasing number of consumer products, such as kitchen utensils, toys, bedding, socks, and trash bags.¹

Uses of Triclosan :

1)      Hand Sanitizer: Triclosan has been shown to be effective in reducing and controlling bacterial contamination on the hands and on treated products. More recently, showering or bathing with 2% triclosan has become a recommended regimen for the decolonization of patients whose skin is carrying methicillin resistant staphylococus aureus (MRSA).² 0.3% triclosan (bacti-stat) is used to eradicate an outbreak of methicillin resistant staphylococcus aureus in several clinical settings e.g. cardiothoracic surgical unit and neonatal nursery.^{3 ,4}

2)      Dental products:

In Dentifrices  (e.g. Janina Diamond Whitening Toothpaste, Pepsodent, Sensodyne Total Care) to prevent gingivitis. According to reviewed extensive effectiveness data on triclosan in Colgate Total toothpaste (1997) it showed that triclosan in this product was effective in preventing gingivitis.

Mouthwashes: Triclosan is incorporated in various mouthwashes (Colgate Total®; Triclosan Mouthwash) and has been used as an antiplaque and anticalculus agent²⁹.

3)      Household Use:  Triclosan is widely used in a wide variety of household products such as

 

A.     Soaps :

• Clearasil® Daily Face Wash
• CVS Antibacterial Soap
• DermaKleen™ Antibacterial Lotion Soap
• Dermatologica® Skin Purifying Wipes
• Dial® Liquid Soap
• Jergens Antibacterial® Antibacterial Cream Soap
• Naturade Aloe Vera 80® Antibacterial Soap
• Provon® Soap
• pHisoderm Antibacterial Skin Cleanser
• Softsoap® Antibacterial Liquid Hand Soap
• Tea Tree Therapy™ Liquid Soap

B.    Deodorant:

• Arm & Hammer Essentials Natural Deodorant
• Old Spice High Endurance Stick Deodorant
• Right Guard Sport Deodorant
• Queen Helene® Tea Trea Oil Deodorant and Aloe Deodorant
• Nature De France Le Stick Natural Stick Deodorant
• DeCleor Deodorant Stick
• Epoch® Deodorant with Citrisomes
• X Air Maximum Strength Deodorant

 

C.       Cosmetics:

• Supre® Café Bronzer™
• Total Skin Care Makeup Kit
• Garden Botanika® Powder Foundation
• Mavala Lip Base
• Jason Natural Cosmetics
• Blemish Cover Stick
• Movate® Skin Litening Cream HQ
• Paul Mitchell Detangler Comb
• Revlon ColorStay LipSHINE Lipcolor Plus Gloss
• Dazzle

 

D.    Other Personal Care Products:

• Gillette® C omplete Skin Care MultiGel Aerosol Shave Gel
• Murad Acne Complex® Kit®
• Diabet-x™ Cream
• T.Taio™ sponges and wipes
• Aveeno Therapeutic Shave Gel

E.         First Aid:

• SyDERMA® Skin Protectant plus First Aid Antiseptic
• Solarcaine®
• First Aid Medicated Spray;
  f.Nexcare™ First Aid
• Skin Crack Care
• First Aid/Burn Cream
• HealWell® Night Splint
• 11-1X1: Universal Cervical Collar with Microban

G.      Kitchenware:

• Farberware® Microban Steakknife Set and Cutting Boards
• Franklin Machine Products FMP Ice Cream Scoop SZ 20 Microban
• Hobart Semi-Automatic Slicer
• Chix® Food Service Wipes with Microban
• Compact Web Foot® Wet Mop Heads

H.        Computer Equipment:

• Fellowes Cordless Microban Keyboard and Microban Mouse Pad

I.        Other:

• Sandals Radio
• Hourglass
• Sounds Around Driver
• Few Laptop
• Toys
• Shoes
• Chef’s Apron
• Socks
• Bionare® Cool Mist Humidifier
• Microban® All Weather Reinforced Hose

• Thomasville® Furniture
• Deciguard AB Ear Plugs
• Bauer® 5000 Helmet
• Aquatic Whirlpools
• Miller Paint Interior Paint
• Escalator Handrails
• Dupont™ Air Filters
• Durelle™ Carpet Cushions
• Advanta One Laminate Floors
• San Luis Blankets
• J Cloth® towels
• Pesticides

Physical Properties of Triclosan:
Molecular formula	C12H7Cl3O2
Molar mass	289.54 g/mol
Melting point	55-57 °C
Boiling point	120 °C, 393 K, 248 °F

Chemical structure and properties

This organic compound is a white powdered solid with a slight aromatic/phenolic odor. It is a chlorinated aromatic compound that has functional groups representative of both ethers and phenols. Phenols often show antibacterial properties. Triclosan is only slightly soluble in water, but soluble in ethanol, methanol, diethyl ether, and strong basic solutions such as 1 M sodium hydroxide. Triclosan can be synthesized from 2,4-dichlorophenol.

IUPAC name Of Triclosan  5-chloro-2- (2,4-dichlorophenoxy) phenol

Mechanism of action

a)                  At in-use concentrations, triclosan acts as a biocide, with multiple cytoplasmic and membrane targets.⁷

b)                   At lower concentrations, however, triclosan appears bacteriostatic and is seen to target bacteria mainly by inhibiting fatty acid synthesis. Triclosan binds to bacterial enoyl-acyl carrier protein reductase enzyme (ENR), which is encoded by the gene FabI.

c)                  The study indicates that the stimulatory effect of IL-1beta on prostanoid formation (PGE2, PGI2) in human gingival fibroblasts was diminished in the presence of triclosan partly at the level of phospholipase A2 and partly at the level of cyclooxygenase. The present data that triclosan, in vitro, inhibits the production of inflammatory mediators such as prostaglandins suggests that this can be an aspect of its clinical effect on gingivitis, in addition to its antibacterial effect.⁸

d)                 Previous studies indicate that triclosan reduces the pain and other symptoms after chemically induced inflammation in the oral mucosa and skin when sodium lauryl sulfate (SLS) is used as an irritant. The aim of the present study was to examine whether triclosan has an effect on the inflammation in human skin caused by intradermal administration of histamine. 9 female volunteers participated in a double-blind study, and skin patch tests were performed in 2 series. In the 1st, the skin was pre-treated for 1 h with triclosan before the histamine was applied. In the 2nd, the histamine reaction was elicited first and triclosan applied subsequently. The effect of triclosan on the weals formed in the skin after histamine application was measured. It was found that triclosan reduced the size of the weals markedly when triclosan was applied after the weals were formed, and that pre-treatment of the skin had only a slight effect. It is assumed that triclosan has an effect on the cascade reactions of inflammation elicited by histamine. 2 other phenols tested in the same study had similar effects.⁹

Pathophysiological role

i.                  In the environment, triclosan may be degraded by microorganisms or react with sunlight, forming other compounds, which include between 3 and 12 % of chlorophenols and dioxin which are extremely toxic and very potent endocrine disruptors. Hence, The United States Environmental Protection Agency (EPA) has registered it as a pesticide.

ii.                  There have been reports of acute health effects such as skin irritation resulting from triclosan exposure. But the more worrisome health effects of triclosan are subtler. Researchers have raised concerns about triclosan and its link to dioxins, which are highly carcinogenic chemicals that can cause severe health problems such as:

1.    Weakening of the immune system,

2.      Decreased fertility,

3.       Altered sex hormones,

4.       Birth defects, and

5.    Cancer.

iii.      Triclosan was found in Greifensee sediment that was over 30 years old,

suggesting that triclosan is degraded or removed slowly in sediment.⁶

 

Resistance

1)      Humans do not have an ENR enzyme, and thus are not affected. Some bacterial species can develop low-level resistance to triclosan at its lower bacteriostatic concentrations due to FabI mutations, which results in a decrease of triclosan’s effect on ENR-NAD⁺ binding, as shown in Escherichia coli and Staphylococcusaureus.^10,11 Another way for these bacteria to gain low-level resistance to triclosan is to overexpress FabI.¹²

2)      Some bacteria have innate resistance to triclosan at low, bacteriostatic levels, such as Pseudomonas aeruginosa, which possesses multi-drug efflux pumps that ‘pump’ triclosan out of the cell.¹³

3)      Other bacteria, such as some of the Bacillus genus, have alternative FabI genes (FabK) to which triclosan does not bind and hence are less susceptible

Resistance concerns

1)      An article coauthored by Dr. Stuart Levy in the August 6, 1998 issue of Nature¹⁴ warned that triclosan’s overuse could cause resistant strains of bacteria to develop, in much the same way that antibiotic-resistant bacterial strains are emerging. In 2003, the Scottish Sunday Herald newspaper reported that some UK supermarkets and other retailers were considering phasing out products containing triclosan.¹⁵

2)      It has since been shown that the laboratory method used by Dr. Levy was not effective in predicting bacterial resistance for biocides like triclosan.¹⁶ At least seven peer-reviewed and published studies have been conducted demonstrating that triclosan is not significantly associated with bacterial resistance over the short term, including one study coauthored by Dr. Levy.¹⁷

Some level of triclosan resistance can occur in some microorganisms, but the larger concern is with the potential for cross-resistance or co-resistance to other antimicrobials. Studies investigating this possibility have been limited.¹⁸

Health concerns

Triclosan is used in a variety of common household products, including soaps, mouthwashes, dish detergents, toothpastes, deodorants, and hand sanitizers.^[19] In the United States, manufacturers of products containing triclosan must indicate it on the label.

1)      A 2010 study linked triclosan usage in children with the development of allergies, suggesting that children with higher exposure to triclosan are more frequently diagnosed with allergies.^20,21,22 Other studies have linked triclosan to allergic contact dermatitis in some individuals.^23,24

2)      Reports have suggested that triclosan can combine with chlorine in tap water to form chloroform,²⁵ which the United States Environmental Protection Agency classifies as a probable human carcinogen. As a result, triclosan was the target of a UK cancer alert, even though the study showed that the amount of chloroform generated was less than amounts often present in chlorinated drinking waters.

3)      Triclosan also reacts with the free chlorine in tap water to produce lesser amounts of other compounds, like 2,4-dichlorophenol.²⁵ Most of these intermediates convert into dioxins upon exposure to UV radiation (from the sun or other sources). Although small amounts of dioxins are produced, there is a great deal of concern over this effect, because some dioxins are extremely toxic and are very potent endocrine disruptors. They are also chemically very stable, so that they are eliminated from the body very slowly (they can bioaccumulate to dangerous levels), and they persist in the environment for a very long time. A 2006 study concluded that low doses of triclosan act as an endocrine disruptor in the North American bullfrog.^[26]

4)      In the study by the University of Florida, researchers found that levels of triclosan were potentially damaging to the unborn foetus, if ingested by the carrying mother. “We know it’s a problem. But we just don’t know how much of a problem. Triclosan can affect blood flow to the uterus, meaning the baby’s brain does not get the oxygen it needs,” said Professor Margaret James, who was the lead-author of the study (the daily mail quoted). In the latest study, tests on sheep showed it interferes with an enzyme that allows the hormone oestrogen to circulate in the womb.

Risk Factors

The most common active ingredient was Triclosan, a chemical i.e. used so commonly, it actually makes its way into our bodies. In 2002, Swedish studies states that high levels of triclosan in 3 out of 5 Human Breast Milk sample is present.

1. The EPA gives triclosan high scores both as a human health risk and as an environmental risk.
2. Triclosan is a chlorophenol, a class of chemicals that is suspected of causing cancer in humans. Externally, phenol can cause a variety of skin irritations, but since it can temporarily deactivate sensory nerve endings, contact with it may cause little or no pain.
3. Taken internally, even in small amounts, phenol can lead to cold sweats, circulatory collapse, convulsions, coma and death. Additionally, chlorinated hydrocarbon pesticides can be stored in body fat, sometimes accumulating to toxic levels.
4. Long-term exposure to repeated use of many pesticide products can damage the liver, kidneys, heart and lungs, suppress the immune system, and cause hormonal disruption, paralysis, sterility and brain hemorrhages.

 

5.   Although it is used as an additive for plastic production used in food packages, but

it has not been approved by the European Commission.⁵

Industry & dentistry urged to take precautions with triclosan

Following various studies on the use of the antibacterial agent triclosan in consumer products, including oral care, experts are urging companies to remove it from their formulations as a precaution.

 

1) Elizabeth Salter Green, director of ChemTrust, a health and environmental body, explained that on a precautionary basis the chemical might not be safe to use at any level. “If one eats the right foods and maintains correct dental hygiene, then triclosan, or other antibacterial agents are not needed,” explained by Salter Green.

2)  The negative effects of triclosan on the environment and its questionable benefits in toothpastes²⁷ has led to the Swedish Naturskyddsföreningen to recommend not using triclosan in toothpaste.²⁸

Removed from GSK’s oral products Oral care giant, GlaxoSmithKline, has removed triclosan from its Aquafresh and Sensodyne toothpastes, as well as its Corsodyl mouthwash, according to the University of Florida which has performed a study on the ingredient in sheep.

Conclusion

Due to inadequate studies and data’s available on triclosan benefits, we should be very cautious about the use of Triclosan in Dental Products. The use of antimicrobial agent, Triclosan, in consumer products has not been studied extensively. No data exists to support their efficacy when used in such products. ³⁰

Any confirmatory studies or data that prove the efficacy of Triclosan in dental products   are still lacking. Moreover it has been a proven accumulative poison and environmental hazardous. Other conventional methods and products are more effective in dental care. So, we should insist on its precautionary withdrawal from the dental products.

Acknowledgement

Authors are grateful to the Dean, Narsinhbhai Patel Dental College and Hospital, Visnagar, India for providing the facilities for conducting the study and Patel Romi, Sharma Arun, Raval Khushbu, Patel Rupal and Shah Utsav (Interns, Narsinhbhai Patel Dental College and Hospital, Visnagar) for providing help.

 

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