Effects of a sodium fluoride- and phytate-containing dentifrice on remineralisation of enamel erosive lesions—an in situ randomised clinical study

• Published in: Clinical oral investigations Vol. 22; no. 7; pp. 2543 - 2552
• Main Authors: Creeth, Jonathan E., Parkinson, Charles R., Burnett, Gary R., Sanyal, Susmita, Lippert, Frank, Zero, Domenick T., Hara, Anderson T.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2018; Springer Nature B.V
• Subjects: Adolescent; Adult; Aged; Clinical trials; Cross-Over Studies; Dental enamel; Dental erosion; Dentifrices; Dentifrices - pharmacology; Dentistry; Double-Blind Method; Enamel; Female; Fluoridation; Fluorides; Hardness; Humans; Male; Medicine; Middle Aged; Mineralization; Original; Original Article; Phytic Acid - pharmacology; Sodium; Sodium fluoride; Sodium Fluoride - pharmacology; Surface Properties; Teeth; Tooth Erosion - prevention & control; Tooth Remineralization - methods; Toothbrushes; Treatment Outcome; Dental erosion; Dentifrice; Fluoride; Polyphosphate; Demineralisation; Remineralisation
• ISSN: 1432-6981; 1436-3771; 1436-3771
• DOI: 10.1007/s00784-018-2351-z

Objective The objective of this work was to evaluate effects of a dentifrice containing sodium fluoride (1150 ppm F) and the organic polyphosphate phytate (0.85% w / w of the hexa-sodium salt) on in situ remineralisation of early enamel erosive lesions and resistance to subsequent demineralisation. Materials and methods Subjects ( n  = 62) wore palatal appliances holding eight bovine enamel specimens with pre-formed erosive lesions. They brushed their natural teeth with the phytate test dentifrice (TD); a positive control dentifrice (PC, 1150 ppm fluoride as NaF); a reference dentifrice (RD, disodium pyrophosphate + 1100 ppm fluoride as NaF) or a negative control dentifrice (NC, fluoride-free) in a randomised, double-blind, crossover design. Specimens were removed at 2, 4 and 8 h post-brushing and exposed to an ex vivo acid challenge. Surface microhardness (Knoop) was measured at each stage. The primary efficacy variable was relative erosion resistance (RER); other variables included the surface microhardness recovery (SMHR), acid resistance ratio (ARR) and enamel fluoride uptake (EFU). Results After 4 h, the results for RER, ARR and EFU were in the order PC > TD  =  RD > NC with PC > TD  =  RD  =  NC for SMHR. Results at 2 and 8 h were generally consistent with the 4 h data. Mineralisation progressed over time. Dentifrices were generally well-tolerated. Conclusions In this in situ model, addition of phytate or pyrophosphate to a fluoride dentifrice inhibited the remineralising effect of fluoride. Both formulations still delivered fluoride to the enamel and inhibited demineralisation, albeit to a lesser extent than a polyphosphate-free dentifrice. Clinical relevance Addition of phytate or pyrophosphate to a fluoride dentifrice may reduce its net anti-erosive properties.