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

Clin Oral Investig. 2018 Sep;22(7):2543-2552. doi: 10.1007/s00784-018-2351-z. Epub 2018 Feb 8.

Abstract

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.

Keywords: Demineralisation; Dental erosion; Dentifrice; Fluoride; Polyphosphate; Remineralisation.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Cross-Over Studies
  • Dentifrices / pharmacology*
  • Double-Blind Method
  • Female
  • Hardness
  • Humans
  • Male
  • Middle Aged
  • Phytic Acid / pharmacology*
  • Sodium Fluoride / pharmacology*
  • Surface Properties
  • Tooth Erosion / prevention & control*
  • Tooth Remineralization / methods*
  • Treatment Outcome

Substances

  • Dentifrices
  • Phytic Acid
  • Sodium Fluoride