Pyrophosphates in toothpaste: a retrospective and reappraisal

During the last 50 years, an increasing number of toothpastes have been marketed that include pyrophosphates as anti-tartar (calculus) agents. Pyrophosphates are chelating agents with low toxicity and a broad range of applications, such as food additives and in industrial applications. Like other chelating agents, the prime function is to combine with metal elements and, in toothpastes, to inhibit calcium phosphate deposits in the form of dental calculus. It is well established that pyrophosphates inhibit crystal growth of hydroxyapatite in bones and teeth, and theoretically may negatively affect the demineralisation-remineralisation equilibrium at the tooth surface. Surprisingly, little clinical research has been carried out to assess if the caries protection provided by fluoride toothpaste is compromised by the inclusion of pyrophosphates and the existing evidence is inconsistent. In the absence of more clinical research, it is suggested that children should not use pyrophosphate-containing toothpastes under 12 years of age.