Recent Development of Active Ingredients in Mouthwashes and Toothpastes for Periodontal Diseases.

Periodontal diseases like gingivitis and periodontitis are primarily caused by dental plaque. Several antiplaque and anti-microbial agents have been successfully incorporated into toothpastes and mouthwashes to control plaque biofilms and to prevent and treat gingivitis and periodontitis. The aim of this article was to review recent developments in the antiplaque, anti-gingivitis, and anti-periodontitis properties of some common compounds in toothpastes and mouthwashes by evaluating basic and clinical studies, especially the ones published in the past five years. The common active ingredients in toothpastes and mouthwashes included in this review are chlorhexidine, cetylpyridinium chloride, sodium fluoride, stannous fluoride, stannous chloride, zinc oxide, zinc chloride, and two herbs-licorice and curcumin. We believe this comprehensive review will provide useful up-to-date information for dental care professionals and the general public regarding the major oral care products on the market that are in daily use.

DNA-assisted upconversion nanoplatform for imaging-guided synergistic therapy and laser-switchable drug detoxification.

The side effects of chemotherapy bring significant physical and psychological suffering to patients. To solve this urgent medical problem, Yb3+ and Er3+ co-doped NaLuF4 upconversion nanoparticles (UCNPs) were constructed for upconversion luminescence (UCL)-labeled diagnosis under 980 nm laser irradiation. The UCNPs were then modified layer by layer with polypyrrole and a special programming DNA segment as photothermal conversion agents and controllable drug carriers, respectively. The nanoplatform was successfully used for imaging-guided synergistic therapy (photothermal therapy and chemotherapy) at a safe power density (300 mW cm-2), and DNA-assisted detoxification at lower temperature in cancer cells when the laser off. The synergistic therapy of the nanoplatform achieved a higher therapeutic index (∼85%) than chemotherapy only (∼44%) and photothermal therapy only (∼25%) in vitro. In vivo experiments also suggested that the nanoplatform had a higher therapeutic effect and lower side effects. The toxicity study was also evaluated, indicating the nanoplatform is low toxic to living system. This multifunctional upconversion nanoplatform provided an innovative method for imaging-guided photothermal-chemotherapy and laser-switchable drug detoxification.

Fluoride loaded polymeric nanoparticles for dental delivery.

The overall aim of the present paper was to develop fluoride loaded nanoparticles based on the biopolymers chitosan, pectin, and alginate, for use in dental delivery. First, the preparation of nanoparticles in the presence of sodium fluoride (NaF) as the active ingredient by ionic gelation was investigated followed by an evaluation of their drug entrapment and release properties. Chitosan formed stable, spherical, and monodisperse nanoparticles in the presence of NaF and tripolyphoshate as the crosslinker, whereas alginate and pectin were not able to form any definite nanostructures in similar conditions. The fluoride loading capacity was found to be 33-113ppm, and the entrapment efficiency 3.6-6.2% for chitosan nanoparticles prepared in 0.2-0.4% (w/w) NaF, respectively. A steady increase in the fluoride release was observed for chitosan nanoparticles prepared in 0.2% NaF both in pH5 and 7 until it reached a maximum at time point 4h and maintained at this level for at least 24h. Similar profiles were observed for formulations prepared in 0.4% NaF; however the fluoride was released at a higher level at pH5. The low concentration, but continuous delivery of fluoride from the chitosan nanoparticles, with possible expedited release in acidic environment, makes these formulations highly promising as dental delivery systems in the protection against caries development.

The use of sodium trimetaphosphate for matrix metalloproteinase inhibition, remineralization and bonding to dentin / O uso de trimetafosfato de sódio sobre a inibição de metaloproteinases e na remineralização e adesão à dentina

The adhesive process to dentin substrate depends on the condition determined by the combined action of the mineral loss and the endogenous enzymes activity. Thus, considering a more complete therapeutic approach, sodium trimetaphosphate (STMP) may be a novel strategy that conciliates the remineralization potential to the promotion of dentin strengthening and its stability, possibly directing mineral nucleation and controlling the rate of biodegradation. In this study, the effect of STMP was evaluated in 2 studies. In study 1, different concentrations of STMP (0.5, 1.5, 3.5 and 5%) were investigated to assess their anti-proteolytic capacity on human purified MMPs-2 and -9 by zymography. Afterwards, only the concentrations (1.5, 3.5 and 5%) that showed total inhibition of both MMPs were used to evaluate their remineralizing capacity in dentin substrate submitted to artificial cariogenic challenge, through surface hardness (SH) and cross-sectional hardness (CSH). In study 2, based on the previous results, the capacity of the 1.5% STMP associated or not with NaF or Ca(OH)2 solutions in improving the dentin bond strength of a universal adhesive system was evaluated by the microtensile test . Thus, these studies suggest that 1.5% STMP is an effective inhibitor of collagen degradation mediated by purified human MMPs-2 and -9. In addition, demineralized and treated dentin with 1.5% STMP supplemented with Ca(OH)2 may induce remineralization. Thus, the use of STMP can be introduced as a new strategy that combines enzymatic inhibition and remineralization potential, reestablishing favorable conditions to affected dentin. These evidences support perspectives of therapies to restructure dentin and propose feasible and promising clinical strategies.(AU)

O processo adesivo ao substrato dentinário depende da condição determinada pela ação combinada da perda mineral e atividade de enzimas endógenas. Deste modo, considerando uma abordagem terapêutica mais completa, o trimetafosfato de sódio (STMP) pode ser uma estratégia inovadora que concilia o potencial remineralizador à promoção do fortalecimento da dentina e sua estabilidade, possivelmente direcionando a nucleação mineral e controlando a taxa de biodegradação. Neste trabalho, o efeito do STMP foi avaliado em 2 estudos. No estudo 1, diferentes concentrações de STMP (0,5; 1,5; 3,5 e 5%) foram investigadas para avaliar sua capacidade anti-proteolítica sobre as MMPs-2 e -9 purificadas humanas, por zimografia. Posteriormente, somente as concentrações (1,5; 3,5 e 5%) que apresentaram capacidade de inibição total de ambas MMPs foram utilizadas para avaliar sua capacidade remineralizadora em substrato dentinário submetido ao desafio cariogênico artificial, através da dureza de superfície (DS) e longitudinal (DL). No estudo 2, baseado nos resultados anteriores, foi avaliada a capacidade do STMP à 1,5% associado ou não a soluções de NaF ou Ca(OH)2 em melhorar a resistência de união à dentina de um sistema adesivo universal pelo teste de microtração. Desta forma, estes estudos sugerem que o STMP à 1,5% apresenta-se como um inibidor eficaz da degradação do colágeno mediada por MMPs-2 e -9 humanas purificadas. Além disso, a dentina humana desmineralizada e tratada com STMP à 1,5% suplementada com Ca(OH)2 pode induzir à remineralização. Assim, o uso de STMP pode ser introduzido como uma nova estratégia que combina inibição enzimática e potencial de remineralização, reestabelecendo condições favoráveis a partir de uma dentina afetada. Estas evidências sustentam perspectivas de terapias para reestruturar a dentina e propor estratégias clínicas factíveis e promissoras.(AU)

Surface degradation of lithium disilicate ceramic after immersion in acid and fluoride solutions.

PURPOSE: To analyze whether immersion in sodium fluoride (NaF) solutions and/or common acidic beverages (test solutions) would affect the surface roughness or topography of lithium disilicate ceramic. METHODS: 220 ceramic discs were divided into four groups, each of which was subdivided into five subgroups (n = 11). Control group discs were immersed in one of four test beverages for 4 hours daily or in artificial saliva for 21 days. Discs in the experimental groups were continuously immersed in 0.05% NaF, 0.2% NaF, or 1.23% acidulated phosphate fluoride (APF) gel for 12, 73, and 48 hours, respectively, followed by immersion in one of the four test beverages or artificial saliva. Vickers microhardness, surface roughness, scanning electron microscopy (SEM) associated with energy dispersive spectroscopy, and atomic force microscopy (AFM) assessments were made. Data were analyzed by nested analysis of variance (ANOVA) and Tukey's test (α = 0.05). RESULTS: Immersion in the test solutions diminished the microhardness and increased the surface roughness of the discs. The test beverages promoted a significant reduction in the Vickers microhardness in the 0.05% and 0.2% NaF groups. The highest surface roughness results were observed in the 0.2% NaF and 1.23% APF groups, with similar findings by SEM and AFM. Acidic beverages affected the surface topography of lithium disilicate ceramic. Fluoride treatments may render the ceramic surface more susceptible to the chelating effect of acidic solutions.

Fluoride Affects Calcium Homeostasis by Regulating Parathyroid Hormone, PTH-Related Peptide, and Calcium-Sensing Receptor Expression.

Parathyroid hormone (PTH), PTH-related peptide (PTHrP), and calcium-sensing receptor (CaSR) play important roles in maintaining calcium homeostasis. Here, we study the effect of fluoride on expression of PTH, PTHrP, and CaSR both in vitro and in vivo. MC3T3-E1 cells and Sprague-Dawley rats were treated with different concentrations of fluoride. Then, the free calcium ion concentration in cell culture supernatant and serum were measured by biochemical analyzer. The expression of PTH, PTHrP, and CaSR was analyzed by qRT-PCR and Western blot. We found that the low dose of fluoride increased ionized calcium (i[Ca(2+)]) and the high dose of fluoride decreased i[Ca(2+)] in cell culture supernatant. The low dose of fluoride inhibited the PTH and PTHrP expression in MC3T3-E1 cells. The high dose of fluoride improved the PTHrP expression in MC3T3-E1 cells. Interestingly, we found that NaF decreased serum i[Ca(2+)] in rats. Fluoride increased CaSR expression at both messenger RNA (mRNA) and protein levels in MC3T3-E1 cells and rats. The expression of PTHrP protein was inhibited by fluoride in rats fed regular diet and was increased by fluoride in rats fed low-calcium diet. Fluoride also increased the expression of PTH, NF-kappaB ligand (RANKL), and osteoprotegerin (OPG) in rats. The ratio of RANKL/OPG in rats fed low-calcium food in presence or absence of fluoride was significantly increased. These results indicated that fluoride might be able to affect calcium homeostasis by regulating PTH, PTHrP, and CaSR.

Evaluation of standardized Bacopa monniera extract in sodium fluoride-induced behavioural, biochemical, and histopathological alterations in mice.

Effect of standardized Bacopa monniera (BM; family: Scrophulariaceae) extract (100 and 300 mg/kg) against sodium fluoride (NaF; 100 and 200 ppm)-induced behavioural, biochemical, and neuropathological alterations in mice was evaluated. Akinesia, rotarod (motor coordination), forced swim test (depression), open field test (anxiety), transfer latency (memory), cholinesterase (ChE), and oxidative stress (superoxide dismutase, catalase, glutathione peroxidase, and lipid peroxidation) were determined in mice treated with NaF for 30 days alone and in combination with BM. NaF induced motor incoordination, depression, and memory impairment, and these were prevented by coadministration of BM in mice. However, NaF did not alter the weight gain, feed/water consumption, and anxiety profile. Suppression of ChE levels and increased oxidative stress were observed in mice treated with NaF. Coadministration of BM significantly improved the memory, ChE levels, and antioxidant enzymes but failed to alter the fluoride levels in NaF-treated mice. Histopathological studies revealed that BM protected the neuropathological alterations induced by NaF.

Fragipan horizon fragmentation in slaking experiments with amendment materials and ryegrass root tissue extracts.

Slaking experiments were conducted of fragipan clods immersed in solutions of poultry manure, aerobically digested biosolid waste (ADB), fluidized bed combustion byproduct (FBC), D-H2O, CaCO3, NaF, Na-hexa-metaphosphate, and ryegrass root biomass. The fragipan clods were sampled from the Btx horizon of an Oxyaquic Fragiudalf in Kentucky. Wet sieving aggregate analysis showed significantly better fragmentation in the NaF, Na-hexa-metaphosphate, and ryegrass root solutions with a mean weight diameter range of 15.5-18.8 mm compared to the 44.2-47.9 mm of the poultry manure, ADB, and FBC treatments. Dissolved Si, Al, Fe, and Mn levels released in solution were ambiguous. The poor efficiency of the poultry manure, ADB, and FBC treatments was attributed to their high ionic strength, while the high efficiency of the NaF, Na-hexa-metaphosphate, and rye grass root solutions to their high sodium soluble ratio (SSR). A slaking mechanism is proposed suggesting that aqueous solutions with high SSR penetrate faster into the fragipan capillaries and generate the critical swelling pressure and shearing stress required to rupture the fragipan into several fragments. Additional fragmentation occurs in a followup stage during which potential Si, Al, Fe, and Mn binding agents may be released into solution. Field experiments testing these findings are in progress.

Topical laser application enhances enamel fluoride uptake and tribological properties.

Topical fluoride treatment prevents dental caries. However, the resulting calcium-fluoride-like deposits are soft and have poor wear resistance; therefore, frequent treatment is required. Lasers quickly heat surfaces and can be made portable and suitable for oral remedies. We examined the morphology, nanohardness, elastic modulus, nanowear, and fluoride uptake of fluoride-treated enamel followed by CO2 laser irradiation for 5 and 10 sec, respectively. We found that laser treatments significantly increased the mechanical properties of the calcium-fluoride-like deposits. The wear resistance of the calcium-fluoride-like deposits improved about 34% after laser irradiation for 5 sec and about 40% following irradiation for 10 sec. We also found that laser treatments increased fluoride uptake by at least 23%. Overall, laser treatment significantly improved fluoride incorporation into dental tissue and the wear resistance of the protective calcium-fluoride layer.

Fluoride-treated bio-resorbable synthetic nonceramic [corrected] hydroxyapatite promotes proliferation and differentiation of human osteoblastic MG-63 cells.

When resorbable hydroxyapatite (HA) granules, which are used as a bone supplement material, were treated in neutral 4% sodium fluoride (NaF) solution, formation of a reactant resembling calcium fluoride was observed on the surface of the granules. Immediate and slow release of fluoride from fluoridated HA (HA+F) granules was observed after immersion in culture fluid, and the concentration increased over time to 1.25 ± 0.05 ppm F at 0.5 hours, 1.57 ± 0.12 ppm F at 24 hours, and 1.73 ± 0.15 ppm F at 48 hours. On invasion assay, migration of human osteoblast-like MG-63 cells exposed to the released fluoride was confirmed in comparison to the cells incubated with a nonfluoridated control sample (P < .01). In addition, fluoride added to the medium increased MG-63 cell proliferation in a manner dependent on fluoride concentrations up to 2.0 ppm (P < .05). At 5.0 ppm, however, fluoride significantly inhibited cell proliferation (P < .005). Activity of the osteogenic differentiation marker, alkaline phosphatase (ALP), also increased with fluoride after exposure for 1 week, increasing significantly at 1.0 ppm (P < .05). The promotion of MG-63 cell migration and proliferation, as well as increased ALP activity, suggested that fluoride released from the surface of resorbable HA granules, which were fluoridated by prior treatment with neutral 4% NaF solution, can provide a superb method to supply fluoride and promote osteogenic cell differentiation.

Effect of resin composites with sodium trimetaphosphate with or without fluoride on hardness, ion release and enamel demineralization.

PURPOSE: To evaluate the effect of the addition of sodium trimetaphosphate (TMP) with or without fluoride on enamel demineralization, and the hardness and release of fluoride and TMP of resin composites. METHODS: Bovine enamel slabs (4 x 3 x 3 mm) were prepared and selected based on initial surface hardness (n = 96). Eight experimental resin composites were formulated, according to the combination of TMP and sodium fluoride (NaF): TMP/NaF-free (control), 1.6% sodium fluoride (NaF), and 1.5%, 14.1% and 36.8% TMP with and without 1.6% NaF. Resin composite specimens (n = 24) were attached to the enamel slabs with wax and the sets were subjected to pH cycling. Next, surface and cross-sectional hardness and fluoride content of enamel as well as fluoride and TMP release and hardness of the materials were evaluated. Data were statistically analyzed using ANOVA (P < 0.05). RESULTS: The presence of fluoride in enamel was similar in fluoridated resin composites (P > 0.05), but higher than in the other materials (P < 0.05). The combination of 14.1% TMP and fluoride resulted in less demineralization, especially on lesion surface (P < 0.05). The presence of TMP increased fluoride release from the materials and reduced their hardness.

Effect of iron II on hydroxyapatite dissolution and precipitation in vitro.

The aim of this study was to evaluate the effect of iron II on the dissolution and precipitation of synthetic hydroxyapatite (HA). HA powder was suspended in solutions of iron (0.84 µg/ml, Fe0.84; 18.0 µg/ml, Fe18; 70.0 µg/ml, Fe70), fluoride (1,100 µg/ml, F1,100), and deionized water and submitted to pH cycling. After pH cycling, the samples were analyzed by infrared spectroscopy and X-ray diffraction. The concentrations of fluoride, calcium, phosphorus, and iron were also analyzed. The data were submitted to ANOVA, and analyzed by Tukey's test (p < 0.05). The infrared spectrum showed a reduction in all bands corresponding to phosphates and hydroxyls and an increase in the carbonate band in the groups with iron. The intensity of the phosphate bands increased and that of the hydroxyl bands decreased in the group F1,100. It was observed that there was a higher concentration of Ca in the group F1,100, with no significant difference between the groups Fe18 and Fe70 (p > 0.05). There was an increase in Fe concentration in the HA directly related to the Fe concentration of the treatment solutions. Results show that the presence of Fe causes the precipitation of apatite with high solubility.

Ameliorative effect of tamarind leaf on fluoride-induced metabolic alterations.

OBJECTIVES: Fluoride is a serious health hazard across several nations, and chronic intake of fluoride deranges the carbohydrate, lipid and antioxidant metabolism in general. As there are limited remedial measures to prevent fluorosis, we investigated the role of tamarind leaf as a food supplement in restoration of carbohydrate, lipid and antioxidant metabolism in fluoride-exposed albino rats. METHODS: Albino rats were exposed to fluoride (100 ppm sodium fluoride) through drinking water and fed diet supplemented with tamarind leaf powder (2.5, 5 and 10 g %) for 4 weeks. Carbohydrate, lipid and antioxidant profiles were investigated in both controls and fluoride-exposed animals. RESULTS: While 4-week exposure to fluoride elevated plasma glucose and lipid profiles, simulating diabetic and hyperlipidaemic conditions, the antioxidant defence mechanisms of fluoride-exposed rats were compromised, with elevation and decline in lipid peroxidation and high-density lipoprotein (HDL)-cholesterol, respectively. When the diet was supplemented with tender tamarind leaves (used in southern India as a replacement for tamarind or other sour food ingredients), significant improvements in carbohydrate and lipid profiles occurred as evidenced by decreased plasma glucose and lipid levels, lipid peroxidation, increased hepatic glycogen content, hexokinase activity and cholesterol excretion, with simultaneous improvement in antioxidant profiles of both hepatic and renal tissues. CONCLUSIONS: These findings are significant in view of the need for cost-effective approaches to tackle fluorosis as an environmental hazard and use of food supplements as ameliorative measures.

Influence of surface roughness on streptococcal adhesion forces to composite resins.

OBJECTIVE: To determine streptococcal adhesion forces with composite resins with different surface roughness. METHODS: Polishing and grinding were applied to obtain smooth (roughness 20 nm), moderately rough (150 nm) and rough (350 nm) surfaces of two orthodontic, light-cured composites. Adhesion forces between Streptococcus sanguinis and Streptococcus mutans and the composite surfaces were measured using atomic force microscopy in absence or presence of a salivary conditioning film. Initial adhesion forces were measured as well adhesion after 120 s of contact, as longer contact times are known to result in stronger adhesion forces ("bond-strengthening"). Surface roughness in absence and presence of salivary conditioning films were compared using ANOVA, while adhesion forces were subjected to a Weibull analysis. RESULTS: Initial adhesion forces in absence of a salivary conditioning film amounted between -0.7 and -0.9 nN for smooth composite resins and increased between -1.0 and -2.0 nN for the roughest surfaces. Streptococcal adhesion forces after bond-strengthening were significantly stronger than upon initial contact, irrespective of the composite type. Salivary conditioning films significantly decreased the surface roughness of the composites, as well as the streptococcal adhesion forces. Yet, also in the presence of a conditioning film, rougher composite surfaces exerted stronger adhesion forces, irrespective of composite type or bacterial strain. CONCLUSION: Streptococcal adhesion forces to orthodontic composite resins increase with increasing roughness of the composite surfaces. Composite surface roughness less affects adhesion forces with S. mutans than with S. sanguinis.

In vivo efficacy of tamarind (Tamarindus indica) fruit extract on experimental fluoride exposure in rats.

The study was undertaken to determine the efficacy of hydro-methanolic (1:1) extract of tamarind (Tamarindus indica L.) fruit pulp in removing body fluoride burden. Thirty rats were divided into five groups. Keeping no fluoride group as the control, rats of no treatment, low dose, middle dose and high dose groups received sodium fluoride orally at the rate of 200mg per kg body weight daily for 14 weeks. Rats of low dose, middle dose and high dose group simultaneously received tamarind fruit pulp extract at three doses, viz. 25 (low), 50 (medium) and 100mg (high) per kg body weight orally, respectively. Fluoride concentration in blood, urine and long bone of experimental rats was monitored to assess the efficacy of the extract. Mean serum fluoride concentration in fluoride exposed rats was 0.145 ± 0.009 and 0.783 ± 0.042 µg/ml on days 0 and 98. In comparison, fluoride concentrations in tamarind treated rats were 0.179 ± 0.021 and 0.633 ± 0.015; 0.179 ± 0.021 and 0.502 ± 0.025 and 0.176 ± 0.021 and 0.498 ± 0.030 µg/ml in low, medium and high dose groups, respectively on day 0 and day 98 of the experiment. There was a significant (p ≤ 0.01) increase in urinary fluoride excretion from day 28 onwards. The mean fluoride concentration in long bones of treated rats was significantly lower than the values recorded in fluoride exposed rats. These findings suggest that concomitant use of tamarind fruit pulp extract can reduce fluoride concentration in blood and bone and enhanced urinary excretion, indicating the ameliorative potential of fruits of tamarind in fluoride toxicity.

Mechanism of action of a desensitizing fluoride toothpaste delivering calcium and phosphate ingredients in the treatment of dental hypersensitivity. Part III: Prevention of dye penetration through dentin vs a calcium- and phosphate-free control.

It is generally accepted that the pain of dental hypersensitivity resulting from gum recession is from the movement of fluid within the exposed tubules of dentin, causing changes in pressure on the nerve within the pulpal cavity. One method of treating hypersensitivity is to occlude the tubules, preventing fluid movement. This article discusses the use of a dye penetration technique, which establishes this mechanism of action for a desensitizing fluoride toothpaste containing calcium and phosphate. Two groups of intact teeth were perfectly sealed with enamel paint. Windows 100-micro to 200-micro deep were opened on opposite sides of each tooth at the dentin-enamel junction and briefly etched using 20% polyacrylic acid. One batch of teeth was treated eight times for 30 mins each with a 1:3 slurry of the desensitizing toothpaste and another set with a similar slurry prepared from a calcium- and phosphate-free control. A 0.85% aqueous solution of acid red fuchsin dye was applied to each window and allowed to dry. After a brief rinse, the teeth were sectioned across the windows. Almost no dye penetration was seen in teeth treated with the desensitizing toothpaste; however, extensive penetration through the dentin was visible in the control-treated teeth. The differences in dye penetration for the two sets of teeth were significant by both subjective (P < .001) and objective (P < .01) measures. Tubule occlusion because of calcium and phosphate ions from the desensitizing toothpaste accounts for its tooth desensitizing efficacy.

Encapsulation of protein in silica matrices: structural evolution on the molecular and nanoscales.

The immobilization of biological species such as proteins and enzymes in sol-gel hosts is currently an area of intense research activity. However, the majority of these studies have been directed toward investigating the biological activity or physicochemical properties of the encapsulated species, with much less attention having been directed toward the effect of proteins on the structural evolution of the sol-gel matrix. This study investigates the structural evolution of sol-gel matrices in the presence of a model protein, bovine serum albumin (BSA). The sol-gel matrices were produced via the NaF-catalyzed hydrolysis of a mixture of tetramethyoxysilane (TMOS) and methyltrimethoxysilane (MTMS), yielding nanohybrid matrices with controlled pore sizes, pore volumes, and surface chemistry. The structural evolution of the matrix was investigated using a complementary suite of techniques, including solid-state (29)Si NMR, FTIR, SANS contrast variation, and N(2) sorption. A novel approach was developed to model the SANS data, to extract key structural parameters. The results indicated that the structural evolution of the matrices was modulated by a series of complex interactions between the enzyme and the evolving sol-gel nanohybrid: On the molecular scale, increasing BSA content led to an associated increase in both the abundance of linear Si-O-Si species (FTIR) and the Qn network connectivity ((29)Si NMR). However, only minor changes in the connectivity of the evolving Tn network were evident with varying BSA content. The selective role of the protein in these systems, where the approach of the methylated monomer to the vicinity of the protein's surface is presumably impeded by the hydrophobicity of the monomer, will be discussed. On the nanoscale, N(2) sorption data were consistent with an initial increase in the mesopore volume and surface area at low BSA loadings, followed by a subsequent monotonic decrease with increasing BSA content. In contrast, no such trends were evident in the in situ SANS data obtained from these samples, suggesting that modulation of the evolving network structure of the silica matrix by BSA during condensation prevents collapse of the nanoscale gel structure during freeze-drying. This latter comparison reflects the important role of in situ techniques such as small angle scattering (which can be used to study both open and closed porosity and probe nanostructure on length scales from approximately 1 nm to >100 nm) in investigating such complex, multicomponent systems, and techniques for modeling such data in sol-gel systems will be discussed.

TiF(4) and NaF at pH 1.2 but not at pH 3.5 are able to reduce dentin erosion.

OBJECTIVE: This study aimed to analyse and compare the protective effect of buffered (pH 3.5) and native (pH 1.2) TiF(4) in comparison to NaF solutions of same pH on dentin erosion. DESIGN: Bovine samples were pretreated with 1.50% TiF(4) or 2.02% NaF (both 0.48M F) solutions, each with a pH of 1.2 and 3.5. The control group received no fluoride pretreatment. Ten samples in each group were eroded with HCl (pH 2.6) for 10x60s. Erosion was analysed by determination of calcium release into the acid. Additionally, the surface and the elemental surface composition were examined by scanning electron microscopy (two samples in each group) and X-ray energy-dispersive spectroscopy in fluoridated but not eroded samples (six samples in each group). Cumulative calcium release (nmol/mm(2)) was statistically analysed by repeated measures ANOVA and one-way ANOVA at t=10min. RESULTS: TiF(4) and NaF at pH 1.2 decreased calcium release significantly, while TiF(4) and NaF at pH 3.5 were not effective. Samples treated with TiF(4) at pH 1.2 showed a significant increase of Ti, while NaF pretreatment increased F concentration significantly. TiF(4) at pH 1.2 led to the formation of globular precipitates occluding dentinal tubules, which could not be observed on samples treated with TiF(4) at pH 3.5. NaF at pH 1.2 but not at pH 3.5 induced the formation of surface precipitates covering dentinal tubules. CONCLUSION: Dentin erosion can be significantly reduced by TiF(4) and NaF at pH 1.2, but not at pH 3.5.

Relationship between tightness of binding and immunogenicity in an aluminum-containing adjuvant-adsorbed hepatitis B vaccine.

Phospholipid-containing antigens, such as Hepatitis B Surface Antigen (HBsAg), adsorb to aluminum-containing adjuvants by ligand exchange of a phosphate group for a hydroxyl group on the adjuvant surface. In this study, a tightness of binding (TOB) assay was developed to characterize the strength of binding between HBsAg and aluminum hydroxyphosphate sulfate adjuvant containing two levels of phosphate. Antigen desorption was induced using either fluoride or phosphate as a competing ion. HBsAg, formulated as a monovalent or combination vaccine, showed decreased tightness of binding when the amount of phosphate in the adjuvant composition increased, indicating that there was less ligand exchange between HBsAg and the adjuvant. Furthermore, the physicochemical property of TOB was related to enhanced immunogenicity in a murine model. These data show that tightness of binding can be a useful characterization tool, and potential predictor of immunogenicity, during development of vaccines that adsorb to aluminum adjuvants via ligand exchange.

Effectiveness of a baking soda toothpaste delivering calcium and phosphate in reducing dentinal hypersensitivity.

OBJECTIVE: The purpose of this controlled clinical trial was to determine the effectiveness and safety of a single-phase dentifrice that delivers calcium, phosphate, and fluoride to the tooth surface (Arm & Hammer Enamel Care for Sensitive Teeth toothpaste, United Kingdom) in reducing dentinal hypersensitivity. METHODS: Two-hundred and eight qualifying subjects were randomly assigned to either the Enamel Care dentifrice group or a control dentifrice group, and brushed twice daily with their assigned dentifrice for eight weeks. Pain/discomfort in response to a thermal stimulus was assessed at baseline, week 4, and week 8 using a Visual Analogue Scale (VAS; primary outcome variable) and the Schiff Thermal Sensitivity Scale (STSS; secondary outcome variable). After eight weeks, volunteers from the Enamel Care group were switched to the control dentifrice and participated in a second eight-week study to determine the degree of persistence of pain reduction. RESULTS: Both groups had statistically significant VAS score reductions from baseline at weeks 4 and 8, with mean VAS scores in the Enamel Care group decreasing by 45.6% at week 4 and 61.1% at week 8 (p < 0.0001). Enamel Care was statistically significantly more effective than the control at weeks 4 and 8, with respective mean VAS reductions of 63% (p < 0.0001) and 33% (p = 0.0004) greater than the control. Consistent with the VAS score results, the Enamel Care group had respective statistically significant STSS score reductions of 77% and 58% greater than the control group (p < 0.0001). The reductions in dentinal hypersensitivity seen in the Enamel Care group at week 8 persisted for an additional eight weeks, during which the subjects discontinued use of Enamel Care and brushed with the control dentifrice. CONCLUSION: Enamel Care for Sensitive Teeth toothpaste (United Kingdom) is an effective dentifrice for the management of dentinal hypersensitivity, and its efficacy persists for a least eight weeks following discontinued product use.