OBJECTIVE: To study and compare the effects of different demineralization-inhibition methods on the shear bond strength (SBS) and fracture mode of an adhesive used to bond orthodontic brackets to demineralized enamel surfaces. METHODS: Eighty freshly extracted, human maxillary premolars were divided into 4 equal groups and demineralized over the course of 21 days. Brackets were bonded to the demineralized enamel of teeth in Group 1. In Group 2, bonding was performed following resin infiltration (ICON(R), DMG, Hamburg, Germany). Before bonding, pre-treatment with acidulated phosphate fluoride (APF) or solutions containing casein phosphopeptide-amorphous calcium phosphate with 2% neutral sodium fluoride (CPP-ACP/wF) was performed in Groups 3 and 4, respectively. The SBS values of the brackets were measured and recorded following mechanical shearing of the bracket from the tooth surface. The adhesive remnant index (ARI) scores were determined after the brackets failed. Statistical comparisons were performed using one-way ANOVA, Tukey's post-tests, and G-tests. RESULTS: Significant differences were found in some of the intergroup comparisons of the SBS values (F = 39.287, p < 0.001). No significant differences were found between the values for the APF-gel and control groups, whereas significantly higher SBS values were recorded for the resin-infiltrated and CPP-ACP/wF-treated groups. The ARI scores were also significantly different among the 4 groups (p < 0.001). CONCLUSIONS: Tooth surfaces exposed to resin infiltration and CPP-ACP/wF application showed higher debonding forces than the untreated, demineralized surfaces.
Acidulated Phosphate Fluoride ; Adhesives ; Bicuspid ; Calcium ; Calcium Phosphates ; Caseins ; Dental Enamel ; Humans ; Oral Hygiene ; Orthodontic Brackets ; Sodium Fluoride ; Tooth

The aim of this study was to compare fluoride release and surface changes according to different orthodontic bracket adhesives the application of fluoride products. We used non-fluoridated composite resin Transbond fluoridated composite resins Blugloo and LightBond, resin-modified glass ionomer Rely XTM Luting 2, and conventional glass ionomer Fuji I®. Fluoride release of five orthodontic bracket adhesives and fluoride release ability after application of three fluoride products (1.23% acidulated phosphate fluoride gel, Tooth Mousse Plus®, Fluor Protector, and a toothbrush with sodium fluoride-containing toothpaste) were measured using a fluoride electrode that was connected to an ion analyzer. After 4 weeks of fluoride application, the surface roughness and surface morphology were examined using a surface roughness tester and field emission scanning electron microscopy. The amounts of fluoride release were observed not only on application of Tooth Mousse Plus® and Fluor Protector on resin-modified glass ionomer Rely XTM Luting 2 and Fuji I®, but also during tooth brushing using fluoride-containing toothpaste. After application of Tooth Mousse Plus®, except Transbond XT, the surface roughness increased, and all orthodontic adhesives showed a partial drop of micro-particle filler. On application of 1.23% acidulated phosphate fluoride gel on all orthodontic bracket adhesives, their surface roughness increased. To bond the orthodontic bracket, resin-modified glass ionomer Rely XTM Luting 2 and Fuji I® adhesives are highly recommended if the amount of fluoride release is considered to confer a preventative effect on dental caries, and among the fluoride products, Tooth Mousse Plus® and Fluor Protector are better than 1.23% acidulated phosphate fluoride gel, and these are expected to prevent dental caries even during tooth brushing with fluoride-containing toothpaste.
Acidulated Phosphate Fluoride ; Adhesives* ; Composite Resins ; Dental Caries ; Dental Cements ; Electrodes ; Fluorides* ; Glass ; Microscopy, Electron, Scanning ; Orthodontic Brackets* ; Sodium ; Surface Properties* ; Tooth ; Toothpastes

No abstract available.
Ecological Systems, Closed* ; Osteoblasts* ; RNA, Messenger* ; Sodium Fluoride* ; Sodium*

Fluoride is one of the most potent stimulators of bone formation in vivo. But its direct effects on osteoblast is not yet clear. This study was to investigate the effects of Sodium fluoride on alkaline phosphatase(ALP) activity, cAMP formation responsive to parathormone(PTH) and type I alpha 2 collagen ribonucleic acid (mRNA) level in Murin osteoblast-like (MC3T3-E1) cells. The cells were cultured in alpha -Minimal essential medium ( alpha -MEM) supplement with 10% fetal bovine serum (FBS) and then changed to 0.1% FBS with various concentration of Sodium fluoride. The ALP activity was assayed by the method of Lowry with disodium phenyl phosphated as substrate. cAMP formation was measured by Radioimmuno Assay(RlA). Type I alpha 2 collagen ribonucleic acid(mRNA) expression was studied by Nothern blot analysis. The results were as follows: 1. cAMP level was increased by PTH in MC3T3-E1 cells. 2. Sodium fluoride showed the tendency of inhibitory effects on cAMP responsiveness to PTH in MC3T3-E1 cells. 3. Sodium fluoride increased ALP activity at cocentration of 2micrometer, 4micrometer, and 10micrometer significantly different from control at the 0.001 level. ALP activity revealed maximum value at 10micrometer in this study. 4. Nothern blot analysis of Sodium fluoride treated cells, using Type I alpha 2 collagen prove, revealed significant increase at 10micrometer in MC3T3-E1 cells.
Alkaline Phosphatase ; Collagen* ; Fluorides ; Osteoblasts* ; Osteogenesis ; RNA* ; Sodium Fluoride* ; Sodium*

OBJECTIVETo study the effect of excessive fluoride on calcium overload and apoptosis in cultured rat ameloblasts in vitro.

METHODSLogarithmic-phase ameloblasts (HAT-7) were treated with 0, 0.4, 0.8, 1.6, 3.2, and 6.4 mmol · L(-1) sodium fluoride (NaF) solution. Cell activities were detected by using a Cell Counting Kit 8 (CCK-8) assay after 48 h of treatment. The effect of fluoride on cell apoptosis was analyzed by using flow cytometry. Excessive fluoride-induced calcium concentration and calreticulin expression changes in ameloblasts were detected by using laser scanning confocal microscopy, Western blot analysis, and real-time quantitative polymerase chain reaction.

RESULTSNaF inhibited ameloblast activity at 1.6, 3.2, and 6.4 mmol · L(-1) (dose-dependent) after 48 h of induction. The Ca2+ fluorescence intensity of HAT-7 cells incubated with 1.6 and 3.2 mmol · L(-1) NaF was higher than that in the control group. The fluoride-induced early-stage apoptosis of ameloblasts after 48 h of induction and the early-stage apoptosis rate was positively correlated with fluoride concentration. Calreticulin mRNA expression in HAT-7 cells was higher than that in the control group after 48 h of incubation with 0.8, 1.2, and 1.6 mmol · L(-1) NaF.

CONCLUSIONExcessive fluoride-induced calcium overload in ameloblasts and further caused endoplasmic reticulum stress-mediated apoptosis.

OBJECTIVETo evaluate the reliability of a method of measuring the total fluoride in fluoride-containing toothpastes with acid diffusion and fluoride selective electrode.

METHODSFour brands of commercially available non-fluoride toothpastes and fluoride-containing toothpastes were sampled. Fluoride was extracted from the toothpastes in 2 mol/L HC10(4) at room temperature overnight and then subjected to the measurement with fluoride electrode.

RESULTSFluoride recovery of the non-fluoride toothpastes containing calcium as abrasive by this method was 99.5%-100.5%, more than 94% of total fluoride was measured from the marketed fluoride toothpastes, and the variation coefficient of this method was less than 1.54%. While the abrasive was silicon, the fluoride recovery of the non-fluoride toothpastes was 83.4%, and 89.7% of total fluoride was measured from the marketed fluoride-containing toothpastes.

CONCLUSIONThe amount of total fluoride in the calcium containing toothpaste can be detected simply and accurately measured by acid diffusion and fluoride selective electrode.

In recent years, though more and more ulcerations of oral mucosa caused by allergy to drug occurred clinically, allergy to sodium fluoride glycerin is extremely rare. A case of allergy to sodium fluoride glycerin occurred in Qianfoshan Campus Hospital of Shandong University. After treatment by sodium fluoride glycerin, there was mucosal edema, a large number of red miliary granules in buccal and palatal mucosa. After 3 hours, there were swallowing difficulties, but no breathing difficulties. Next day large ulcers of oral mucosa developed. The patient was cured 7 days after treatment. Fluoride-sensitive test result was positive.
Fluorides ; Glycerol ; Humans ; Hypersensitivity ; Male ; Mouth Mucosa ; Phosphates ; Sodium Fluoride

OBJECTIVETo evaluate the capability of quantitative light-induced fluorescence (QLF) for monitoring the remineralization of lesions lengthways and distinguishing the effect of different fluorides.

METHODSFollowing baseline early caries examination, 305 school students (age from 11 to 14 years old)were qualified from Chengdu area. The schools in which the subjects studied were randomized into three groups: NaF group, MFP group and nonfluoride group. The subjects of three groups brushed the teeth with 1450 mg/L sodium fluoride dentifrice, 1450 mg/L sodium monofluorophosphate dentifrice and non-fluoride dentifrice, respectively. QLF images of early lesions on smooth surfaces of the maxillary anterior teeth were taken at baseline, three and six months after the initiation of experiment. These images were analyzed by the trained examiner with the area of lesion (Area), fluorescence loss (deltaF) and gross fluorescence loss quantity (deltaQ).

RESULTS296 school students completed the study. After three months, the lesions on smooth surfaces got better in all three groups. The change of Area, deltaF and lg deltaQ amongst three groups had no statistical significance (P>0.05). After six months, the lesions on smooth surfaces also got better in all three groups than at baseline. The change of Area, deltaF and lg deltaQ of the lesions in NaF group and MFP group exhibited significant decreases than that of no-fluoride dentifrice group (P<0.05). But no significantly difference was found between NaF group and MFP group (P>0.05).

CONCLUSIONAs a diagnostic method which could quantify the miner content, QLF system has the capability of monitoring the variations of lesions lengthways.

OBJECTIVEThis study aims to determine the effect of fluoride concentration on the corrosion behavior of cobalt-chromium alloy fabricated by two different technology processes in a simulated oral environment.

METHODSA total of 15 specimens were employed with selective laser melting (SLM) and another 15 for traditional casting (Cast) in cobalt-chromium alloy powders and blocks with the same material composition. The corrosion behavior of the specimens was studied by potentiodynamic polarization test under different oral environments with varying solubilities of fluorine (0, 0.05%, and 0.20% for each) in acid artificial saliva (pH = 5.0). The specimens were soaked in fluorine for 24 h, and the surface microstructure was observed under a field emission scanning electron microscope after immersing the specimens in the test solution at constant temperature.

RESULTSThe corrosion potential (Ecorr) value of the cobalt-chromium alloy cast decreased with increasing fluoride concentration in acidic artificial saliva. The Ecorr, Icorr, and Rp values of the cobalt-chromium alloy fabricated by two different technology processes changed significantly when the fluoride concentration was 0.20% (P < 0.05). The Ecorr, Icorr, and Rp values of the cobalt-chromium alloy fabricated by two different technology processes exhibited a statistically significant difference. The Icorr value of the cobalt-chromium alloy cast was higher than that in the SLM group cobalt-chromium alloy when the fluoride concentration was 0.20% (P < 0.05). The Ecorr, tRp alues of the cobalt-chromium alloy cast were lower htan those of the SLM group cobalt-chromium alloy when the fluoride concentration was 0.20% (P< 0 .05).

CONCLUSIONFluoride ions adversely affected the corrosion resistance of the cobalt-chromium alloy fabricated by two different technology processes. The corrosion resistance of the cobalt-chromium alloy cast was worse than that of the SLM group cobalt-chromium alloy when the fluoride concentration was 0.20%.

To understand the micro-mechanical changes and the effects of the fluoride on rat's femur after administration of sodium fluoride, the threepoint bending test, acoustic emission analysis during the three-point bending test and scanning electron microscopy were performed. The obtained results were as follows: 1. Bone strength increased in the rats given 1, 5, 10 and 20 ppm of fluoride but, there were no statistical significances (p > 0.05). 2. With increasing the concentration of fluoride, most AE events released rapidly just before the maximum load and smaller events were recorded than the control group's. The average of cumulative AE event counts until maximum load of the femur in 20 ppm group were significantly small with respect to the control group's (p < 0.05). 3. Fracture surfaces were well coincide with the results of acoustic emission behavior. Analyses of fracture surfaces indicated that, consistent with its the highest load, rat femur in 20 ppm fluoride group displays the roughest surface.
Acoustics* ; Animals ; Femur* ; Fluorides ; Microscopy, Electron, Scanning ; Rats* ; Sodium Fluoride* ; Sodium*