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Composite hydrogel films are prepared by photocros-slinking of partially polymerized poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) prepolymer solution dispersed with aragonite precipitated calcium carbonate (PCC) particles. The effects of PCC aspect ratio (AR, 4.2-6.6) and volume fraction ([Φ.sub.PCC]) are studied with respect to the prepolymer viscosity, the maximum packing fraction ([Φ.sub.m]), and optical properties. [Φ.sub.m] obtained from Kreigher-Dougherty fitting is found to decrease with increasing AR of PCC particles, from [Φ.sub.m]= 0.33 (AR=4.2) to [Φ.sub.m]= 0.21 (AR=6.6). Scanning electron microscopy images revealed that the particles are uniformly dispersed and randomly orientated in the polymer network when [Φ.sub.PCC], INTRODUCTION Hydrogels are three-dimensional polymeric networks that can absorb a large amount of water, while maintaining the network structure. They play important roles in many biological applications, including drug delivery, [...]

Objective. The objective of this research was to evaluate the caries control potential of a new fluoridemouthrinse that also contained antimicrobial agents and a biofilm disrupting agent using different in vitro models. Methods. Four in vitro studies were conducted to assess the performance of this three pronged approach to caries control: (1) traditional enamel fluoride uptake, (2) surface microhardness study usingpHcyclingmodel and subsequent fluoride uptake, (3) a salivary biofilm flow-through study to determine the anti-microbial activity, and (4) a single species biofilm model measuring effect on biofilm matrix disruption. Results. The data showed that a LISTERINE rinse with fluoride, essential oils and xylitol was superior in promoting enamel fluoride uptake and in enhancing antimicrobial activity over traditional commercially available fluoridated products. An increase of the surface microhardness was observedwhen the LISTERINE rinse was used in combination with fluoridated toothpaste versus the fluoridated toothpaste alone. Finally, itwas demonstrated that xylitol solutions disrupted and reduced the biovolume of biofilmmatrix of mature Streptococcus mutans. Conclusion. These in vitro studies demonstrated that a fluoride mouthrinse with antimicrobial agent and biofilm matrix disrupting agent provided multifaceted and enhanced anti-caries efficacy by promoting remineralization, reducing acidogenic bacteria and disrupting biofilm matrix. [ABSTRACT FROM AUTHOR]

Purpose: To review the published literature on clinical caries trials of fluoride dentifrices and to combine their results in order to evaluate the correlation between fluoride concentration in dentifrice formulations and their anticaries efficacy, i.e., the dose-response relationship. Methods: All available dentifrice caries clinical trials reported in the literature of products having at least two fluoride concentrations greater than 0 ppm were reviewed, graphed and statistically analyzed, Results: The evaluation supported a linear correlation between the fluoride concentration of dentifrices between 0 and 5000 ppm F and clinical caries efficacy. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the expected anticaries efficacy of a new dentifrice containing stannous fluoride as the anticaries agent and potassium nitrate as the antihypersensitivity agent using a series of laboratory and animal studies. Methods: Four surrogate studies were performed in this assessment including fluoride uptake in sound enamel, enamel solubility reduction, fluoride bioavailability and animal caries. Results: Each of these studies indicated the new dentifrice for hypersensitivity (Colgate Sensitive Maximum Strength) was effective in inhibiting the caries process. The data demonstrate that this new dentifrice is predicted to be highly effective against caries and equivalent to a positive control dentifrice. [ABSTRACT FROM AUTHOR]

Purpose: To measure the inward flux of potassium across human dentin disks, in vitro, in the absence and then in the presence of a simulated pulpal pressure (PP), before and after brushing with two desensitizing dentifrices. Materials and Methods: Dentin discs were made from extracted unerupted third molars and etched with 6% citric acid to remove the smear layers. The hydraulic conductance (Lp or outward fluid movement) of the discs was measured before and after brushing for 2 minutes with two desensitizing dentifrices, Colgate Sensitive Maximum Strength or Sensodyne Fresh Mint, both dentifrices containing 5% potassium nitrate. The potassium flux was measured at a pressure of 0 cm H2O, and a simulated pulpal pressure of 30 cm H2O. Results: The results showed the Colgate-brushed specimens had lower Lp (P< 0.05) than specimens brushed with Sensodyne or with saline. The Colgate-brushed specimens had a corresponding lower K+ flux, at a PP = 0 cm H2O, than specimens brushed with saline, but were not significantly different than specimens brushed with Sensodyne dentifrice. However, when the pressure was increased from 0 to 20 cm H2O, to simulate outward dentin fluid pressure, there were significant decreases in K+ flux across all three treatment groups, but the K+ flux of the Colgate-brushed specimens were affected the least, resulting in the Colgate-brushed specimens having significantly (P < 0.05) greater K+ fluxes than the saline or Sensodyne dentrifice-brushed groups. The magnitude of reduction in K+ flux in going from 0 cm H2O to 20 cm H2O was demonstrated to be linearly related to the magnitude of the Lp of the brushed specimens. Hence, a small Lp corresponded to a small reduction in K+ flux, and a correspondingly large K+ flux at 20 cm H2O. An explanation of this phenomenon is that a decrease in the Lp of dentin, produced by brushing, corresponds to a decreased outward dentin fluid flow. This lowers the outward K+ convective flow and also lowers the inward K+ diffusion. However, since the decrease of the outward K+ convective flow is greater than the decrease of the inward K+ diffusion, and the net flux is the algebraic sum of these two terms, the result is greater net inward K+ flux through the dentin. Therefore, the Colgate-brushed specimens, which exhibited the lowest Lp, provided the greatest inward K+ flux at simulated dentin fluid pressure. [ABSTRACT FROM AUTHOR]

'Soft' nanomaterials have the potential to produce substantive antibiofilm effects. The aim of this study was to understand the oral antimicrobial activity of soft nanomaterials generated from alpha-tocopherol (α-T) and alpha-tocopherol phosphate (α-TP). (+) α-TP formed planar bilayer islands (175 ± 21 nm, -14.9 ± 3.5 mV) in a Trizma® buffer, whereas (+) α-T formed spherical liposomes (563 ± 1 nm, -10.5 ± 0.2 mV). The (+) α-TP bilayers displayed superior Streptococcus oralis biofilm growth retardation, a more substantive action, generated a superior adsorption to hydroxyapatite and showed an enhanced inhibition of multi-species bacterial saliva biofilm growth (38 ± 7μm vs 58 ± 18 μm, P ˂ 0.05) compared to (+) α-T. Atomic force microscopy data indicated that the ability of the 'soft' α-TP nanomaterials to transition into planar bilayer structures upon contact with interfaces facilitated their adhesive properties and substantive antimicrobial effects., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)