Browsing by Subject "Remineralisation"

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    Effects of a sodium fluoride- and phytate-containing dentifrice on remineralisation of enamel erosive lesions—an in situ randomised clinical study
    (Springer, 2018-02-08) Creeth, Jonathan E.; Parkinson, Charles R.; Burnett, Gary R.; Sanyal, Susmita; Lippert, Frank; Zero, Domenick T.; Hara, Anderson T.; Cariology, Operative Dentistry and Dental Public Health, School of Dentistry
    ObjectiveThe 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 methodsSubjects (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).ResultsAfter 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.ConclusionsIn 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 relevanceAddition of phytate or pyrophosphate to a fluoride dentifrice may reduce its net anti-erosive properties.
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    Remineralisation of enamel erosive lesions by daily-use fluoride treatments: network meta-analysis of an in situ study set
    (Springer, 2024-12-26) Creeth, Jonathan; Smith, Gary; Franks, Billy; Hara, Anderson; Zero, Domenick; Biomedical and Applied Sciences, School of Dentistry
    Objectives: Daily-use fluoride products are first-line protection against enamel wear from dietary-acid exposure (DAE). This study aimed to understand effects of fluoride concentration, fluoride salt, product form and ingredients in daily-use products on remineralisation and demineralisation, via network meta-analysis (NMA) of 14 studies using one well-established in-situ model. Remineralisation (surface-microhardness recovery, SHMR) after treatment, and protection against subsequent demineralisation (acid-resistance ratio, ARR) were measured. Materials and methods: Healthy participants, wearing intra-oral palatal appliances holding enamel specimens eroded with standardised DAE, used test products once. Enamel hardness was assessed (Knoop microhardness probe) pre-DAE; post-DAE; after 4 h intra-oral remineralisation; and after post-remineralisation DAE. NMA was performed using a mixed-models approach on subject-level data to estimate and compare means. Results: There was a dose-response for fluoride ion in toothpastes (0-1426ppm F; p < 0.001 for SMHR and ARR). One toothpaste (silica-based, 1150ppm F as NaF) showed a benefit for SMHR versus placebo [mean(standard error)]: 8.8%(0.6%) (33.0% vs. 24.2%; p < 0.001); for ARR: 0.27(0.03) (0.43 vs. 0.15; p < 0.001; 9 mutual studies). Use of fluoride mouthwash after fluoride toothpaste increased SMHR [2.4%(1.1%); p = 0.043; 3 studies]; the effect on ARR [0.08(0.05)] was not significant (p = 0.164). Negative effects of polyvalent metal ions and polyphosphates on SMHR (p < 0.05) were observed. Conclusions: NMA proved effective in discriminating between fluoride-based treatments in this in-situ study, highlighting the importance of fluoride ion to enamel protection and showing formulation ingredients can affect its performance. Clinical relevance: Daily-use fluoride products can protect enamel against dietary acids, but careful formulation is required for optimal performance.