Inter-method reliability for determining total and soluble fluorides in child low-fluoride formula dentifrices

Erosion Effects of OTC Paediatric Oral Liquids and Traditional Chinese Medicine on Primary Teeth

BACKGROUND

This study compared the in vitro erosive effects of 2 western and 2 Chinese medicinal over-the-counter paediatric medications on primary teeth in a continuous time scale.

METHODS

Twenty enamel blocks obtained from 10 deciduous incisors were randomly assigned into 5 groups (n = 4 each): Group GA and Group GB-paracetamol liquid (Jean-Marie Pharmacal Co. Ltd and Universal Pharmaceutical Laboratories Ltd, respectively); Group GC and Group GD-reconstituted Chinese medicinal granules (Huarun 999 and Guizhou Bailing Group Pharmaceutical Co. Ltd, respectively); and deionised water (control group). The pH levels of these liquids were assessed. The immersion process was repeated for 20 rounds. For each round, each sample was immersed in liquid for 15 seconds and then rinsed with deionised water for 15 seconds. Mean hardness ratio (MHR) at 5, 10, 15, and 20 rounds was evaluated using Vickers microhardness test. The initial and final surface morphology and chemistries were analysed by scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS).

RESULTS

All 4 liquid medications have shown acidic pH (4.74-5.76). After 20 rounds of immersion, the MHR20 of the GA (0.886) and GB (0.930) groups decreased significantly from the original MH0. The GC (0.978) and GD (0.985) groups illustrated a similar trend as the deionised water control group (0.985). Despite EDS, chemical analysis showed an increase of Ca/C mole ratio after drug immersion, and no significant difference (P > .05) was found on the ratios Ca/P and Ca/C and the amounts of magnesium or sodium before and after immersion according to the Wilcoxon signed-rank analysis. Distinctive enamel loss with irregular craters, and a corroded surface with fracture lines along the border of prism head were observed in the SEM of groups GA and GB, respectively. However, findings in both Chinese medicine groups were similar, such that erosive changes were barely seen, similar to the control group.

CONCLUSIONS

This study concluded that the pH of liquid medication may not be a significant factor that contributes to enamel softening. Traditional Chinese granule medications may be a safer option for primary teeth.

Enamel Remineralisation with a Novel Sodium Fluoride-Infused Bristle Toothbrush

This study aims to investigate whether toothbrushes with fluoride-infused bristles have any (re)mineralisation effects on bovine enamel. Bovine incisors (N = 160) were extracted, and the buccal side of the crown was cut into dimensions of ~5 mm × 5 mm with a low-speed saw. These specimens were randomly allocated into four groups: half (80 teeth) were stored in demineralising solution (DM), and the other half were stored in deionised water (DW) for 96 h. Then, they were brushed with a force of 2.0 ± 0.1 N for five min with a manual toothbrush with either fluoride-infused (TF) or regular (TR) bristles. Microhardness (Vickers), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) were used to investigate the surfaces of the bovine enamel specimens before and after brushing. Two-way ANOVA was used to analyse the hardness data, and the pairwise comparison method was used to analyse the Ca/P ratio, for each group at α = 0.05. The results show that brushing with either of these toothbrushes increased the Vickers microhardness on DM and DW enamel (p < 0.001), whereas hydroxyapatite was revealed in all groups by XRD. The DM samples showed a significant increase (p < 0.05) in the Ca/P ratios after brushing with TR and TF. Conversely, under DW conditions, these ratios decreased significantly after brushing. In terms of the F atomic%, TF increased significantly. SEM revealed mineral deposition in the DM groups after toothbrushing. To conclude, toothbrushing effectively induces the microhardness of sound and demineralised enamel, while fluoride-infused bristles might be able to retain fluoride on the enamel surface.

Optimization of a Validated Protocol That Determines Bioavailable Fluoride in Toothpastes

A validated protocol used to determine how much of total fluoride is bioavailable in toothpaste formulations was evaluated if it could be simplified regarding the following parameters: (1) concentration of the slurry (0.25-4%), (2) centrifugation speed (1,000-12,000 g) and time (1-10 min), and (3) incubation time for FPO32- ion hydrolysis and insoluble-F dissolution (15-60 min). Fresh and aged Na2FPO3/CaCO3 and fresh NaF/SiO2-based toothpastes were analyzed (n = 9). The improvements were the centrifugation at 1,000 g for 5 min is enough to separate insoluble-F and the time for FPO32- ion hydrolysis and insoluble-F dissolution can be shortened to 30 min.

Fluoride content in paediatric dentifrices commercialized in Brazil

OBJECTIVES

The aim of this study is to determine the total, soluble and ionic fluoride (IF) concentration in toothpastes for children since there is a lack of information about this data.

METHODS

Fifteen different brands of toothpastes were purchased in different cities in Brazil. The total fluoride (TF), total soluble fluoride (TSF) and IF of two samples of each brand were determined (μg/g F).

RESULTS

The concentration of TF found in the fluoride toothpastes ranged from 324.4 to 1466.2 μg/g F, TSF ranged from 214.6 to 1424.1 μg/g F and IF ranged from 108.3 to 1320.1 μg/g F. TSF ranged between TF and IF. Most toothpastes were formulated with sodium fluoride (NaF), and only one with monofluorophosphate (MFP). The concentrations of TF were below the reported values. TSF and IF were below the TF concentration.

CONCLUSIONS

The measured TF was less than that declared by the manufacturer in all the products. Most of the evaluated fluoride toothpastes commercialized in Brazil showed concentrations of TF below what was stated on the packaging, but with enough TSF to provide an anti-caries effect.