New Oral-B Pro-Health: one toothpaste with the benefits of many

Oral-B is positioned to become a major player in the toothpaste market in Australia for the first time following its launch of Oral-B Pro-Health, a dentifrice containing both stabilised Stannous Fluoride and Sodium Hexametaphosphate suitable for everyday use.

More than 15 years in the making and backed by over 100 clinical and scientific studies, Oral-B Pro-Health marks a scientific breakthrough, offering demonstrated effectiveness against plaque; caries; gingivitis; sensitivity; enamel erosion; calculus; staining; and halitosis.

The combination of stabilised stannous fluoride and sodium hexametaphosphate solves the two major concerns which have limited the use of stannous fluoride in oral care products in the past - its stability in the product and its tendency to cause discolouration. This new toothpaste can impact positively on oral health through multiple mechanisms based on its unique combination of active ingredients.

Stannous fluoride delivers long-lasting antimicrobial benefits against a wide range of bacteria, including oral species linked with dental caries, periodontal disease and oral malodour. In vitro and in vivo studies on the antimicrobial activity of stannous fluoride have proposed a variety of potential mechanisms of action, including the inhibition of bacterial growth and adhesion and interference with bacterial metabolic processes.

Table 1. Properties of Stannous Fluoride and SodiumHexametaphosphate

Studies have also shown that stannous fluoride produces strong activity against plaque acid production as well as inhibition of regrowth, with subsequent and significant reductions in lactic, acetic and total acids.

Pro-Health has also exhibited long-lasting antibacterial actions against salivary bacteria by producing significant bactericidal activity that lasted at least 16 hours after a 60-second exposure of the salivary organisms to the toothpaste. The activity of Pro-Health on plaque metabolism was also found to be very effective, extensively reducing plaque acid production immediately and at 45 minutes after exposure.

Stannous fluoride dentifrices
Pro-Health was first launched under the Crest brand in 2006 in the US market and has since secured a significant market share.

Procter & Gamble, who own both the Oral-B and Crest brands, have a long history in stannous fluoride-based dentifrices. As early as 1946, the company was researching toothpastes to prevent tooth decay and in 1950, began supporting the work of Dr Joseph Muhler at Indiana University who was investigating the benefits of fluoride. It was Dr Muhler who identified stannous fluoride as being the most effective type of fluoride and by 1953, he had perfected the formula for “Fluoristan”, which was commercialized as Crest with Fluoristan and launched in 1955.

Crest swapped to using Sodium Fluoride as its active ingredient following issues with “Fluoristan”. Although widely recognized as an effective multibenefit therapeutic agent, stannous fluoride’s use has been limited by its chemical instability in aqueous solutions and by aesthetic considerations, such as astringent taste and mild extrinsic dental staining in some patients with prolonged use.

A number of approaches have been used in the past to minimize the stability and aesthetic issues associated with stannous fluoride, with limited success.

It wasn’t until 1995 that Crest re-entered the market with a stannous fluoride-based product, Crest Gum Care, for use in specific indications, however research efforts continued to develop a dentifrice for every day use.

Sodium hexametaphosphate
Procter & Gamble’s ongoing investment in oral-health related innovation, research and development next lead to the discovery of sodium hexametaphosphate’s advanced calculus and stain-control properties. This polymer demonstrated an ability to inhibit calculus formation and new stain formation whilst also whitening teeth via extrinsic stain removal. Commencing in 1999, P&G marketed Crest Dual Action Whitening and Crest Vivid White toothpastes containing sodium hexametaphosphate.

Like stannous fluoride, sodium hexametaphosphate also suffered stability issues. These were eventually overcome through the use of a low-water system in a silica-based dentifrice formulation that significantly minimizes the hydrolysis of sodium hexametaphosphate and thus helps to maintain effective levels of polyphosphate for activity. These same techniques were also adapted to eventually perfect the combination of stannous fluoride with sodium hexametaphosphate that lead to the development of Pro-Health.

Dentinal hypersensitivity
As well as antiplaque and antigingivitis effects, the clinical efficacy of stannous fluoride for the prevention and control of dentinal hypersensitivity has been demonstrated extensively. These effects have been attributed to the partial or complete occlusion of dentinal tubules by insoluble precipitates or solid complexes formed by the reaction of stannous fluoride with enamel or dentine surfaces.

Anti-caries effects
The anti-caries efficacy of stannous fluoride dentifrices has been demonstrated in more than 40 clinical studies. Fluoride is known for its ability to inhibit demineralization and enhance remineralisation of partially demineralised enamel. Additionally, stannous fluoride exhibits strong reactivity with enamel and root surfaces, forming insoluble precipitates that coat the surface of these biomaterials and thereby provide protection against acid challenges. Another widely recognized function of stannous fluoride in caries prevention has been its ability to reduce bacteria that cause dental caries, i.e., Streptococci mutans, most notably in patients at high risk for caries, including patients with orthodontic appliances and patients with reduced salivary flow. The anti-caries effects of stannous fluoride, therefore, comprise a combination of physical chemical effects and antimicrobial actions.

Anti-erosion effects
The deposition of stannous fluorophosphate or stannous oxide layers onto enamel surfaces have also been reported and this helps prevent dental erosion. This occurs primarily as a result of the attachment of the stannous ion to free phosphate (PO) sites on the surface of enamel with the stannous forming a protective layer that is highly resistant to acids. Clinical and in vitro studies have also demonstrated Pro-Health’s combination of stannous fluoride and sodium hexametaphosphate offers superior protection against erosion over conventional fluoride products.

Anti-calculus effects
The primary mechanism for the anti-calculus actions of sodium hexameta-phosphate is plaque mineralisation inhibition via inhibition of crystal nucleation and growth. Studies have demonstrated significant reductions in hydroxyapatite crystal growth and plaque mineralisation when sodium hexametaphosphate was delivered either from an aqueous solution or a dentifrice vehicle.

Extrinsic whitening effects
In addition to producing significant reductions in calculus formation, sodium hexametaphosphate whitens through chemical stain control, which includes both stain-prevention and stain-removal activities. Because of its strong affinity for and enhanced retention to calcium phosphate in enamel, dentin and dental calculus, sodium hexametaphosphate exhibits considerable influence on the stain chromogen adsorption/desorption chemistry, pellicle film chemistries and bacterial detachment from pellicle-coated hard tissue surfaces. These effects lend support to the theory that the clinical stain-control efficacy of sodium hexametaphosphate is derived from the superior actions of polymer chains interacting via chemical actions with the stain-trapped pellicle films.

Anti-Halitosis
A final benefit of Oral-B Pro-Health is reducing oral malodour. The combination of stannous fluoride and sodium hexametaphosphate reduces and inhibits both Gram-positive and Gram-negative bacteria.

Oral malodour is primarily a result of anaerobic Gram-negative bacteria breaking down amino acids, resulting in volatile sulphur compounds (VSCs) being produced. Reductions in oral malodour as well as a breath freshening effect have been demonstrated in controlled clinic trials with short-term overnight use of Oral-B Pro-Health as well as longer term over a period of several weeks.

Summary
The benefits of Oral-B Pro-Health include protection against pathogenic and odour-causing bacteria, plaque, gingivitis, dentinal hypersensitivity, caries, and calculus as well as whitening through extrinsic stain control. Oral-B Pro-Health is the only all-in-one dentifrice that contains an advanced stannous fluoride/sodium hexametaphosphate technology to deliver this unique combination of therapeutic and cosmetic benefits recommended by dental professionals.

Reference materials
This article draws extensively from material contained in an article, A Novel Dentifrice Technology for Advanced Oral Health Protection: A Review of Technical and Clinical Data by Dr Arif Baig and Tao He published in Compendium.

For the launch of Oral-B Pro-Health, Oral-B has compiled an extensive evidence base available to dental professionals in Australia on request. Studies supporting all claims made in this article relating to the efficacy of Pro-Health are included in this material.