妊娠期大鼠摄入氟化物对子代鼠血液和骨氟浓度的影响

目的:观察孕期大鼠摄入不同剂量的氟之后,对子代鼠血液和骨氟浓度及软骨细胞和骨关节结构的影响,以探索通过妊娠期母体给氟预防乳牙龋齿的新途径。方法:给妊娠SD大鼠分别用N aF按1 m g/kg体重、10 m g/kg体重和50 m g/kg体重灌胃至分娩,并用0.9%N aC l灌胃作为对照组。结果:①实验组各组子鼠血清中的氟化物含量均较对照组高(P<0.01);并且与母鼠摄入的氟剂量呈正相关。②在中、高剂量组子鼠上肢骨骨氟的含量明显高于对照组。③在高剂量组子鼠的上肢骨切片中可见软骨细胞和关节结构的破坏。结论:①妊娠期母体摄入的氟化物可进入其子体体内。②当母鼠摄入的氟化物剂量过高时,可引起骨组织的毒性损害。     

Sodium trimetaphosphate enhances the effect of 250 p.p.m. fluoride toothpaste against enamel demineralization in vitro

This in vitro study investigated the effect of sodium trimetaphosphate (TMP), added to toothpaste containing 250 p.p.m. fluoride, on enamel demineralization. Bovine enamel blocks (n = 96) were subjected to five pH cycles over a 7‐d period and treatment with suspensions of toothpastes containing 0, 250, 500, and 1,100 p.p.m. fluoride (as sodium fluoride), as well as with 250 p.p.m. fluoride containing TMP at 0.25, 0.5, 1.0, and 3.0%. Treatment with toothpaste suspensions was performed under agitation twice a day, for 1 min. Surface and cross‐sectional hardness, and fluoride firmly bound to enamel, were quantified. Data were subjected to one‐way anova , followed by Tukey's test. Low‐fluoride toothpastes containing TMP at 0.25–1.0% resulted in enamel mineral loss similar to that seen for the toothpaste containing 1,100 p.p.m. fluoride. Also, the addition of TMP to the toothpaste containing 250 p.p.m. fluoride promoted enamel fluoride concentrations similar to those obtained for the 500 p.p.m. fluoride group. The toothpaste containing 250 p.p.m. fluoride and 0.25% TMP led to the lowest mineral loss among all groups. It was concluded that the addition of as little as 0.25% TMP to a toothpaste containing 250 p.p.m. fluoride can reduce enamel demineralization to levels similar to those seen for a conventional toothpaste containing 1,100 p.p.m. fluoride, in vitro.     

Fluoridated toothpaste: usage and ingestion of fluoride by 4‐ to 6‐yr‐old children in England

Fluoridated toothpaste is effective for dental caries control, yet may be a risk factor for dental fluorosis. This study aimed to quantify fluoride ingestion from toothpaste by children and to investigate the effects of age, gender, and social class on the amount of fluoride ingested per toothbrushing session. Sixty‐one children, 4–6 yr of age, were recruited: 38 were from low socio‐economic (LSE) areas of Newcastle, UK, and 23 were from high socio‐economic (HSE) areas of Newcastle, UK. All expectorated saliva, rinse water (if used), and residual toothpaste were collected after brushing at home and were analysed for fluoride. Of the children, 74% and 69% from HSE and LSE areas, respectively, claimed that they brushed twice per day. The mean (SD) weight of toothpaste dispensed was 0.67 (0.36) g. The mean (SD) amount of fluoride ingested per toothbrushing session and per day was 17.0 (14.7) and 29.3 (32.8) μg kg^?1 of body weight, respectively. Daily fluoride intake per kilogram of body weight did not differ significantly between children from LSE and HSE areas. Fluoride intake per toothbrushing session was significantly influenced by weight of toothpaste, its fluoride concentration, and the child's age. Whilst the average amount of toothpaste used per toothbrushing session was more than twice the recommended amount (of 0.25 g), only one child had a daily fluoride intake that exceeded the tolerable upper intake level of 0.1 mg kg^?1 of body weight for this age group.     

Anti‐erosive effects of fluoride and phytosphingosine: an in vitro study

A selection of commercially available products containing stannous fluoride (SnF₂)/sodium fluoride (NaF), SnF₂/amorphous calcium phosphate (ACP), SnF₂/NaF/ACP, tin (Sn)/fluorine (F)/chitosan were compared with phytosphingosine (PHS) with respect to their anti‐erosive properties in vitro. One‐hundred and twenty bovine enamel specimens were immersed in the respective product slurries for 2 min, twice daily. The formulations were diluted with either remineralization solution or artificial saliva. After each treatment, an erosive challenge was performed for 10 min, twice daily, using citric acid, pH 3.4. The specimens were stored in remineralization solution or artificial saliva until the next treatment‐erosion challenge. After 10 d, tissue loss was determined using profilometry. Enamel softening was determined through surface microhardness measurements. Tissue‐loss values (measured in μm and expressed as mean ± SD) for PHS, SnF₂/NaF, SnF₂/ACP, SnF₂/ACP/NaF, and Sn/F/chitosan treatment groups and for the negative‐control group, were, respectively, 35.6 ± 2.8, 15.8 ± 1.8, 22.1 ± 2.0, 22.9 ± 1.8, 16.2 ± 1.2, and 51.2 ± 4.4 in the presence of remineralization solution and 31.7 ± 3.3, 15.6 ± 2.9, 16.5 ± 2.7, 16.8 ± 2.1, 13.1 ± 3.0, and 50.7 ± 2.8 in the presence of artificial saliva. There were no significant differences in surface microhardness measurements between the treatment groups. In conclusion, PHS resulted in a significant reduction of tissue loss compared with the negative control, but in comparison, the toothpastes containing Sn²⁺ and F^? ions were significantly more effective compared with PHS.     

Identification of early vascular calcification with 18F-sodium fluoride: potential clinical application

Vascular calcification plays a prominent role in cardiovascular disease. Once considered to be a passive consequence of aging, this pathological process is now accepted to be dynamic and tightly regulated, its onset triggered by inflammation and necrosis and its progression bearing key similarities to osteogenesis. A major potential advance in our ability to understand the natural history and clinical implications of vascular calcification is the detection of its early and dynamic stages through the use of the positron-emitting radiotracer, ¹⁸F-sodium fluoride. Alongside anatomical information gained from computed tomography, hybrid positron emission and computed tomography (PET/CT) imaging with ¹⁸F-sodium fluoride has, for the first time, enabled the non-invasive detection of microcalcification within the aortic valve, great vessels, and vulnerable coronary plaque. This has raised promise that exploring this process may allow improved risk prediction, better application of current therapies and ultimately the development of novel treatments to target this widespread pathology.     

Inhibition of dentin matrix‐bound cysteine cathepsins by potassium fluoride

Matrix metalloproteinases (MMPs) and cysteine cathepsins (CCs) can break down unprotected type I collagen fibrils in dentin matrix. This study investigated the use of potassium fluoride (KF) as a potential inhibitor of MMPs and CCs in dentin. Demineralized dentin beams were divided into groups (n = 10 in each group) and incubated in artificial saliva (AS, control), either alone or with one of seven concentrations of KF (6–238 mM fluoride) for 1, 7, and 21 d. After 21 d, all groups were further aged in AS for 6 months. Total MMP activity was screened using the colorimetric MMP assay. The activities of MMP‐2 and MMP‐9 were investigated using gelatin zymography. At the end of each incubation, changes in loss of dry mass and CC‐mediated or total dissolution of collagen peptides were measured via precision weighing, C‐terminal crosslinked telopeptide of type I collagen (CTX), and hydroxyproline (HYP) assays. The beams were examined using scanning electron microscopy. After 21 d, total MMP activities, dry mass loss, and CTX release for the groups exposed to 179 and 238 mM fluoride were significantly lower compared with the control group. After 6 months, all groups showed similar total MMP activity, dry mass loss, and HYP release, and CTX levels were significantly lower when the fluoride concentration was ≥24 mM. Calcium fluoride (CaF₂)‐like precipitates were observed over the beams. In summary, KF significantly inhibited the catalytic activity of dentin matrix‐bound CCs but did not seem to be effective for MMP‐mediated activity.