The Editorial Executive Committee welcomes letters, which should be less than 250 words. Before a decision to publish is made, letters which refer to a published article may be sent to the author for a response. Any letter may be sent to an expert for comment. When letters are published, they are usually accompanied in the same issue by their responses or comments. The Committee screens out discourteous, inaccurate or libellous statements. The letters are sub-edited before publication. Authors are required to declare any conflicts of interest. The Committee's decision on publication is final.
Letter to the editor
Editor, I refer to Professor Reynolds' excellent review of the safety implications of toothpaste ingredients (Aust Prescr 1994;17:49-51).
Probably the agents most likely to cause an allergic reaction are methyl and propyl parahydroxybenzoates, which seem to be the most commonly used preservatives in toothpastes available in Australia. As far as I am aware, SensodyneF (regular and gel) and the entire Aim and Colgate ranges are free of any preservative.
Professor Reynolds' discussion of the potential hazards of ingestion of silicareminds me that, not only are siliceous earths used as abrasives, but also that hydrated silica (silica gel), colloidal anhydrous silica and aluminium magnesium silicate are often used as thickening/binding agents. A few toothpastes are silica free, including Macleans Regular Mint, OralB Dental Paste, Colgate Fluoriguard (regular and cool mint only), Ultrabrite and Dentagard.
The use of gum arabic (gum acacia), gum tragacanth and Indian tragacanth (karaya) as binders/thickeners is less common nowadays due to a possibility of sensitization reactions. Carrageenan gum (which incidentally is identical to Irish Moss extract), guar gum, xanthan gum, silica compounds and cellulose derivatives seem to be the most commonly used.
The only sorbitol free toothpaste that I can trace is Macleans Smokers Toothpaste! Of course, sorbitol is not the only potential laxative in toothpastes since several of the thickening/binding agents may exert this effect if swallowed in sufficient quantity.
Toothpastes containing 0.3% triclosan, as a plaque inhibiting antibacterial, are currently readily available (e.g. Colgate Total and the Aim range).
Senior Lecturer in Pharmacology
Department of Dentistry
University of Adelaide
- Machackova J, Smid P. Allergic contact cheilitis from toothpastes. Contact Dermatitis 1991;24:311-2.
- Andersen KE. Contact allergy to toothpaste flavours. Contact Dermatitis 1978;4:195-8.