Sodium Lauryl Sulfate and Canker Sores


Arianna Ritchey, RDH

Sodium Lauryl Sulfate and Canker Sores

There are many different types of toothpastes available to consumers, and there are a variety of benefits available in each of the different types of toothpastes related to their active ingredients.  With so many different ingredients present in toothpastes, some toothpastes may cause an unpleasant or even allergic reaction inside the mouth.  One ingredient commonly found in toothpaste that can cause reactions in some patient is Sodium Lauryl Sulfate, also known by its abbreviation, SLS.  

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SLS is a foaming agent that creates that nice, rich foam we expect from our soaps and toothpastes. It’s also a detergent, and thus strips away hard-to-get-rid of fats.  Similar to other detergents, SLS can be an irritant to those with sensitive skin or a sensitivity to SLS itself.  SLS is found in many shampoos, soaps, and is used to create a foaming action in all Colgate brand toothpastes and Crest brand toothpastes.  

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The most common reaction to SLS in the mouth is the development of aphthous ulcers, more commonly known as canker sores.  Canker sores are benign ulcerations of the soft tissues that can range from a minor irritation to a major ulcer which can be quite painful.   While the actual cause of canker sores is unknown, certain factors are recognized as triggers of the onset of a canker sore.  Any type of trauma to the mucus lining of the mouth can trigger a canker sore, be it inadvertently biting the tongue or cheek, or perhaps a food irritant such as chocolate, mustard, nuts, tomatoes, shellfish, and or pineapple.  An irritant like SLS may also trigger canker sore development.

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At this time there are no treatments to prevent a canker sore, but once they have developed, canker sores may be treated palliatively with a topical anesthetic, like Orajel.  Another option for treatment is laser therapy by a laser-certified dental hygienist, or dentist.  Heat from the laser is used to kill any virus present and to stimulate the body’s healing potential.  Laser treatments take about 15 minutes and most patients feel better immediately following treatment.  

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If you are experiencing recurrent sores in your mouth, many dental professionals recommend switching to a toothpaste without SLS to see if that helps resolve the issue.  Two toothpastes which are SLS-free and are accepted by the American Dental Association are Rembrandt Premium Whitening Mint Toothpaste, and Sensodyne ProNamel Mint Essence Toothpaste.  


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If mouth sores persist after the discontinuation of a SLS toothpaste, this may be an indication of a nutritional deficiency, including deficiency in iron, folic acid, and other B vitamins.  Vitamin supplements or an improved diet may eliminate these deficiencies, but it is advisable to ask your physician for a nutritional assessment.

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