The role of sodium polyphosphates - Veterinary Practice
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The role of sodium polyphosphates

Lee Danks in this ninth in a series from Royal Canin focusing on innovations in small animal nutrition looks at the benefits of sodium polyphosphates in veterinary diets with regard to dental health

PERIODONTAL disease (PD) is the most common infectious disease in cats and dogs with a prevalence that approaches 80%.1 It is an in ammatory oral disease seeded by the development of dental plaque.

Periodontal disease might be described as a combination of periodontal inflammatory reactions with varied clinical characteristics – local or generalised; acute or chronic; mild or aggressive. These focus on the periodontal tissues, namely the gingiva, periodontal ligament, cementum and the alveolar bone of the maxillae and mandible.

All stages are possible: from early-stage PD to moderate or severe forms, and different scales are used. Progression of PD depends on the level of mechanical removal of that seeding cause, dental plaque, but it’s also dependent on the local immune response of each individual.

With such a high prevalence, it’s plain that much PD is going undiagnosed in practice and unrecognised by pet owners.

As a source of chronic pain which often becomes a long-standing bacterial disease with wide-ranging effects throughout the rest of the body, we should be smart in understanding, diagnosing and communicating this condition to those who visit us in practice.

Dental plaque is a deposit on the surface of the tooth, consisting of bacteria amalgamated within an organic matrix. Plaque begins to calcify within 72 hours: the bacteria in the plaque shift to an anaerobic population which “ x” calcium ions and produce hardened mineral accumulations in the form of tartar.

This calcium originates in either the saliva or the gingival fluid in which the gingival crevice (or sulcus) is immersed to form  supra-gingival and sub-gingival plaque respectively. Tartar is actually a deposit of calcium carbonate and calcium phosphate which accumulates on the tooth surface, notably around the gingival margin.

Role of dental diets

Pet food manufacturers like Royal Canin meticulously analyse how dry kibble interacts with the oral environment. The size, shape and texture of dry diets can improve the control of dental plaque and tartar.

Unlike what might be described as the more “sticky” viscous wet diets, the physical properties of a dental kibble mean that it is able to mimic the effects of tooth-brushing. This is influenced by diet composition and technical specifications in production, quantitatively assessed by what we call a texturometer.

One further effort a manufacturer might take, with the target of combatting calculus (or tartar), is the addition of sodium polyphosphates.

The efficacy of sodium polyphosphates in curbing the development of calculus is well known and clinically validated: Calcium (Ca2+) cations in the saliva are required for the mineralisation step by which plaque is converted into calculus and polyphosphates work to interfere with this step.

They are released in the oral cavity to naturally trap or “chelate” the calcium in the saliva in its ionic form, limiting its integration in the dental calculus matrix. The calcium is then released normally in the digestive tract so that it can be absorbed in accordance with the individual’s needs.

The mechanical friction effect of kibbles on teeth can therefore be amplified if the kibbles are coated by calcium binders. This coating is one of the very last steps of the manufacturing process to be sure of maximal efficacy.

Free calcium in the saliva is minimised and this feature sets some dental diets aside from others. By inhibiting crystal formation, polyphosphates prevent plaque from becoming mineralised and subsequently, soft plaque may better be (and earlier) removed by the mechanical actions of the kibble.


Depending on your approach, conventional treatment of periodontitis can be split into three stages. Firstly, therapy should start with client education and establishing an appropriate at-home oral-care regime. Secondly, address the associated conditions and risk factors which may accompany the disease (geriatric changes, renal insufficiency, local and systemic infections where PD is advanced). The third step is to eliminate the plaque and calculus in the here and now by means of a scale and polish.

The success of the treatment you choose is ultimately based on long-term maintenance of good oral hygiene and it’s here that our owners’ efforts are key. Although tooth brushing is the gold standard method of plaque removal, it is not practically feasible for some dogs and many cats (and their owners!). For this reason, specifically adapted “dental” diets such as those provided by Royal Canin are now widely accepted as an effective support for oral hygiene.

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  1. Lund, E. M., Armstrong, P. J., Kirk, C. A. et al (1999) Health status and population characteristics of dogs and cats examined at private veterinary practices in the United States. J Am Vet Med Assoc 214: 1,336-1,341.
  2. Hennet, P., Servet, E., Soulard, Y. and Biourge, V. (2007) Effect of pellets size and polyphosphates in preventing calculus accumulation in dogs. J Vet Dent 24: 236-239.
  3. Clarke, D. E., Servet, E., Hendriks, W. et al (2010) Effect of kibble size, shape and additives on plaque in cats. J Vet Dent 27: 84-90.

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