The evolution of plaque removal

Dec. 18, 2014
Contemporary toothpaste targets changing the 'enabling' factor with bacteria and tooth surfaces

Contemporary toothpaste targets changing the 'enabling' factor with bacteria and tooth surfaces

BYPeter L. Jacobsen, PhD, DDS

Fossil evidence documents that plaque dates back at least 50,000 years to the Neanderthals.1 Perhaps even they worried about how to get it off before it calcified into tartar, improving oral comfort or as a part of natural grooming.

The first recorded efforts at plaque control focused on physical removal, essentially scrubbing it off with a stick or brush.2 The use of a chewing stick dates back to ancient times, and there is even mention that Siddhartha (Buddha) used a chewing stick to clean his teeth. Different plants are chosen for chewing sticks in different cultures and locations around the world. Interestingly, a close look at the chemistry of the plants used as chewing sticks reveals that many contain compounds with antimicrobial properties, such as the miswak twig used in the Middle East.3

At some point - perhaps there was sand left on the chewing stick - people noticed that some abrasive added to the stick improved plaque removal. People also used ground-up bone, as well as the crystals that formed in the bottom of red wine bottles and barrels to clean their teeth. Today, most toothpastes contain very clean, very fine abrasive particles, such as silica, calcium carbonate (chalk), silicon dioxide (sand), dicalcium phosphate, and alumina to help remove the plaque.

Next, soap (sodium lauryl sulfate) was added to the mix to break up the surface tension and to help with the cleaning process. Soaps and detergents are still an important ingredient in most toothpastes today. That is the reason almost all toothpastes foam.

Toothpastes continued to evolve from the traditional soap and abrasive model to the new "modern" toothpastes introduced in the early 1900s, containing the addition of chemicals such as calcium fluoride and later sodium fluoride. During the 1950s, stannous fluoride was added to fight dental decay. Potassium nitrate was added in the 1970s as a desensitizer, and triclosan was added in the 1990s as an antimicrobial. A recent Cochrane Review meta-analysis of 30 studies documented the efficacy of this most recent additive in reducing plaque and gingivitis by 22%. It also documented a 48% reduction in gingival bleeding when compared to a fluoride-only toothpaste.4

It is now one hundred years after the first modern toothpaste was invented, and patients' only choices are still to scrub teeth with brushes, sands, and soaps, killing plaque with bacteria-killing chemicals.

Rethinking Plaque Control and Toothpaste

To control plaque effectively, you must look at the chemistry of plaque formation. The electrical charge on the surface of teeth is negative and the charge on the surface of bacteria is also negative. Two similarly charged surfaces normally electrostatically repel each other. Based on that electrostatic chemistry, the teeth should repel the plaque, just like two magnets put together at similar ends repel each other.

But, of course, that doesn't happen. Plaque sticks to teeth.

A closer look at the chemistry of plaque reveals that something gets between the negatively charged surface of the tooth and the negative surface of the bacteria, enabling the bacteria to stick to teeth. That enabler is the positively charged calcium (Ca++) ion in the saliva. The positive charge of salivary calcium reduces the natural negative charge of both the bacteria and the tooth surface. This masking of negative charges prevents the teeth from repelling the bacteria. Instead, the calcium allows the bacteria and the tooth surface to get closer together. At this point, another attractive force, called van der Waals force, which is effective at very short distances, takes over and allows the bacteria to stick to the teeth.

Adhesion of the bacteria to the tooth surface is the foundation for what is scientifically referred to as the biofilm, the plaque that we see on teeth. It is the source of a variety of oral cavity problems, including dental decay, halitosis, gingivitis, and periodontal disease.

As the biofilm grows, it continues to concentrate the calcium, not only out of the saliva, but also from the surface of the teeth, essentially fueling this unhealthy attraction. In fact, calcium is concentrated in the plaque fluid, reaching levels two to three times higher than the levels found in saliva.

Besides masking the negative charge of the bacteria, the higher calcium concentration in the biofilm stimulates bacteria to excrete exopolysaccharides (glucan, for example) at eight to 10 times their normal rate and aggregate them into a sticky gel.5,6 This sticky gel acts as a shield protecting the bacteria from dislodgement. It also prevents antibacterial compounds from effectively reaching the bacteria in the biofilm.

The increased calcium also causes bacteria to produce fibrils, or pili, which are used to anchor the bacteria to the teeth, to the mucosal surfaces, and to each other.7 These pili inject toxins into the gingiva, which leads to inflammation. These growing collections of bacteria, which are now firmly attached to the surface of the teeth, create bacterial colonies that are the foundation of dental plaque. Essentially, teeth become little petri dishes for the bacteria to grow on.

Eventually the plaque, because of the high concentrations of calcium, calcifies into calculus, an ideal biofilm environment that firmly attaches to the teeth. Once calculus has formed, it must be professionally removed.

Disabling the Enabler

The obvious answer is to disable the enabler, the calcium in the plaque fluid.8 If we can achieve this, then there would be no unhealthy attraction of bacteria to the teeth, no secretion of exopolysaccharides to create the fabric of the biofilm and hold it together, and no development of the bacterial pili that anchor the bacteria to the gingiva and each other and are a major source of inflammation.

The result of decreasing calcium levels in the biofilm would be a dramatic reduction of plaque in the oral cavity. Additionally, removing the plaque would also allow the salivary calcium ions to perform their real job of remineralizing tooth surface directly, instead of being interrupted and bound up by the plaque.

A close look at this chemistry by a team of researchers has led to the realization that a class of compounds called chelators should inactivate the unhealthy calcium in the biofilm. The problem in using chelators is that, like biofilm, chelators are also negatively charged. Since similar charges repel, the available chelators have never been able to penetrate through the biofilm to get to the calcium.

The scientists at Livionex have succeeded in finding a way to activate the FDA-approved, food-safe chelator, edathamil, so that the negative charges of the chelator are masked. This allows the edathamil to penetrate into the biofilm and reduce the calcium levels in the plaque fluid. The activated edathamil, in the form of a dental gel, is brushed on like any other toothpaste and strategically disrupts the calcium levels in the biofilm, resulting in a dramatic reduction in plaque.

Livionex Dental Gel delivers results that no other toothpaste has ever been able to achieve. And it is done without the abrasives, detergents, or antimicrobials found in traditional toothpastes.

A double blind plaque control study was conducted in the United States, comparing the Livionex Dental Gel with a leading triclosan-containing toothpaste.8 The study documented that Livionex Dental Gel, with activated edathamil, is significantly more effective at reducing plaque, reducing gingival inflammation, and reducing gingival bleeding than the control toothpaste, which as discussed earlier is more effective than standard fluoride toothpaste. Results showed an 84% improvement in plaque reduction, a 64% greater reduction in gingival inflammation, and a 39% greater reduction in gingival bleeding over the control triclosan-containing toothpaste.8

There is general agreement in the dental profession that good plaque control will have many oral health benefits, including a reduction in gingivitis and bleeding. Livionex Dental Gel represents a new and more effective approach to the chemistry and method of plaque and gingivitis control. This new plaque-reducing gel is not only more effective, but also eliminates concerns about safety, because it doesn't contain any soaps, abrasives, or harsh chemicals. Its effect is mediated by a compound, activated edathamil, which is considered by the FDA as safe enough to be used in food. This is a level of safety not shared by any of the active ingredients in any of the other leading, ADA-accepted plaque-control toothpastes.

Because of its effectiveness and safety, it is a good choice for all dental patients, especially for those who are not achieving good plaque control with their present toothpaste. It is also an excellent choice for those patients who are concerned about chemicals in their oral-care products. It is also useful for patients with special plaque control needs, such as those with orthodontic brackets, those with oral appliances, and in patients with gingivitis and periodontitis. It reduces plaque in the difficult-to-reach areas of the gingival margins and interproximal spaces and thereby eliminates the inflammation and odors associated with plaque buildup.

According to the British Medical Journal, over 90% of adults have gingivitis. The recently published Centers for Disease Control and Prevention (CDC) report states that over 47% of all U.S. adults have periodontitis.10Given these epidemic occurrences of oral disease, Livionex Dental Gel has the potential to be an easy-to-use innovation that can vastly improve future oral care. RDH

Peter L. Jacobsen, PhD, DDS, is an adjunct professor at the Arthur A. Dugoni School of Dentistry in San Francisco. Dr. Jacobsen is widely recognized as an expert in oral medicine, speaking nationally on the topics of dental pharmacology and over-the-counter dental products. He also consults and sits on the scientific advisory committees of several oral-care product companies.


1. Barras C. Neanderthal dental tartar reveals evidence of medicine, New Scientist, 18 July 2012,

2. Eid MA, et al. Relationship between chewing sticks (miswak) and periodontal health. Part 1. Review of the literature and profile of the subjects, Quintessence Int., 1990 Vol 21 Number 11/1990: 913-917.

3. Wu CD, Darout IA, Skaug N. Chewing sticks: timeless natural toothbrushes for oral cleansing. J.Periodontal Res. 2001 Oct;36(5):275-84.

4. Riley P, Lamont T. Triclosan/copolymer containing toothpastes for oral health, Editorial Group: Cochrane Oral Health Group, Published Online: 5 DEC 2013, Assessed as up-to-date: 19 AUG 2013, DOI: 10.1002/14651858.CD010514.pub2.

5. Patruchan MA, et al. Calcium influences cellular and extracellular product formation during biofilm-associated growth of a marine Pseudoalteromonas sp, Microbiology. 2005 Sep;151(Pt 9):2885-97.

6. Sarkisova S, et al. Calcium-induced virulence factors associated with the extracellular matrix of mucoid Pseudomonas aeruginosa biofilms, J Bacteriol. 2005 Jul;187(13):4327-37.

7. Johnson MD. The Effect of Calcium Binding on Adhesion and Pilus Biogenesis in the PilC Family of Proteins, PhD Thesis 2011, University of North Carolina, Chapel Hill.

8. Martinez-Gil, et al. Calcium causes multimerization of the large adhesin LapF and modulates biofilm formation by Pseudomonas putida, J Bacteriol. 2012 Dec;194(24):6782-9.

9. Ralston et al. Comparison of Plaque Removal Capabilities between Two Dentifrices, Oral Hyg Health 2014, 2: 157. doi: 10.4172/2332-0702.1000157.

10. Eke PI, Dye B, Wei L, Thornton-Evans GO, Genco RJ. Prevalence of periodontitis in adults in the United States: 2009 and 2010. J Dent Res 2012; 91:914-20.