Acid wear: the caries of the 21st century

GlaxoSmithKline (GSK) has commenced the next phase of its consumer campaign aimed at increasing the awareness of the problems of acid wear. Following the launch of their latest toothpaste brand, Pronamel, earlier this year, GSK aired a series of testimonial-based television commercials featuring Sydney dentist Anthony Goswell. This latest phase of the campaign has seen press briefings with leading women's and consumer magazines held to coincide with a visit by Dr David C. Alexander, GlaxoSmithKline's Director of Worldwide Dental Affairs.

"We see acid wear as a major threat to the oral health of the population," Dr Alexander said. "Acid wear is effectively the caries of the 21st century and we want to increase awareness of the problem.

"As teeth are healthier and last longer with fewer restored surfaces, they are suffering more wear and tear. Healthier diets and lifestyles are also inadvertently impacting on our dentition and we need to educate people on how to adapt the way they look after their teeth to ensure they remain healthy.

"If you look at the evolution of toothpaste, we introduced fluoride in the 1960's and it was seen as being therapeutic. In the 70's and 80's however, we lost sight of this. Toothpaste became more of a grooming tool and it was marketed as being able to give you fresher breath, whiter teeth, the ability to control tartar and so on.

"We forgot about the properties of fluoride because you got it whether you wanted it or not. During that period, there were a lot of other ingredients added into toothpaste to achieve those grooming related properties and some of these compromised the effects of the fluoride.

"The bioavailability of fluoride differs markedly from brand to brand despite all having the obligatory 1000 parts per million (the upper limit allowed by the TGA for over the counter toothpastes). In reality however, the fluoride can bind to other ingredients.

"By the time it gets onto your toothbrush, not all of those 1000 parts per million are available. It then becomes a slurry when it mixes with your saliva and the detergents and thickening agents present further compete with the effectiveness of the fluoride.

"What GSK has done with Pronamel is to revisit the whole concept of toothpaste and take a pharmaceutical approach. In effect, viewing toothpaste as a drug delivery system with the drug being fluoride. We asked the question, how do we optimise the system to make it more effective.

"Pronamel is no wonder drug or magic bullet; rather we went back to basics and looked at how can we deliver as much of those 1000 parts per million to the tooth as possible."

According to GSK, Pronamel fluoride uptake is optimised through a combination of a netural pH, low abrasiveness and a formula free of Sodium Lauryl Sulphate (SLS). The latter is an excellent detergent, but it has been suggested that it may strip the smear layer. The smear layer contains calcium, phosphate, fluoride, and also acts as a protective barrier. Pronamel instead uses the detergent cocamidopropyl betaine for a gentler clean, leaving more of the smear layer intact.

The critical pH at which enamel can demineralise is reported to be approximately pH 5.5 (Newby CS et al.The Journal of Clinical DentistryVol XV11. 4.94-99). The critical pH for dentine demineralisation is reported to be between pH 6.0 and 6.8. Pronamel has been designed to have a neutral pH of approximately 7.1.

Dental-type silicas act as polishing and cleaning agents to assist in the removal of food and remnants from teeth. The grade of silica in Pronamel provides an abrasivity level which is low relative to other pastes, but will still clean effectively, and is within the recommended level of ISO 11609 for dentifrice product.

Dr Alexander said that GSK has conducted extensive testing to gauge both the fluoride uptake and also the physical change in the microhardness of teeth brushed with Pronamel.

"Our tests have shown that using Pronamel, the surface of your teeth is harder and thus more resistant to acid attack ," he said. "We test all the toothpastes on the market and we know that by brushing with Pronamel, you receive at least a 20% improved fluoride uptake over the market leading brand."

Dr Alexander emphasised during the briefing that while Pronamel will help combat acid wear on your teeth, lifestyle changes were also necessary to maintain a health dentition.

"The way we were taught to look after our teeth many years ago made certain assumptions and some of those assumptions have now changed, particularly based on our diets and the greater longevity of our natural dentition. With Pronamel, we are trying to help educate consumers about how to modify their oral care routines to ensure they reduce the effects of acid wear and keep their teeth strong and healthy for life."

Dr Alexander gained his BDS from the School of Dental Surgery, University of Liverpool, England in 1975 and Membership in General Dental Surgery of the Royal Colleges of both England and Edinburgh in 1984. He then completed a Master of Science in Community Dentistry at the University of London, and a Residency in Dental Public Health at the National Institute for Dental and Craniofacial Research in the US.

Before joining GSK, he was involved in the training and education of both dental hygienists and dentists at both the undergraduate and postgraduate levels. He has published over 35 papers and presented lectures at scientific meetings throughout the world. As GSK's senior dentist, he is based in the United States and supports the company's oral health activities by helping dental professionals worldwide understand more about the therapeutic conditions in which the company carries out research and the development of new products.