Plasma proteins in the acquired denture pellicle enhance substrate surface free energy and Candida albicans phospholipase and proteinase activities

2014 ◽  
Vol 6 (4) ◽  
pp. 273-281 ◽  
Author(s):  
William Custodio ◽  
Wander J. Silva ◽  
Adriana F. Paes Leme ◽  
Jaime A. Cury ◽  
Altair A. Del Bel Cury
2014 ◽  
Vol 6 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Wander J. da Silva ◽  
Cristiane Maria B. Leal ◽  
Flávia C. Viu ◽  
Letícia M. Gonçalves ◽  
Célia Marisa R. Barbosa ◽  
...  

2010 ◽  
Vol 428-429 ◽  
pp. 186-193 ◽  
Author(s):  
Wen Jun Zheng ◽  
Chen Yan Chiang ◽  
Chi Wi Ong

The effect of temperature on the tilt of discotic columns in a columnar phase has been studied. The homogenous alignment of discotic columns is achieved by applying a mechanical shearing. In the columnar phase, the tilt of the discotic columns at substrate surface is found to change with temperature. A decrease in the temperature of the substrates causes an increase in the pretilt of the discotic columns. The phenomenon is explained based on the consideration of surface free energy at the interface of the substrate.


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1534
Author(s):  
Andrea Schubert ◽  
Ralf Bürgers ◽  
Franziska Baum ◽  
Oliver Kurbad ◽  
Torsten Wassmann

Microbial adhesion to oral splints may lead to oral diseases such as candidiasis, periodontitis or caries. The present in vitro study aimed to assess the effect of novel computer-aided design/computer-aided manufacturing (CAD/CAM) and conventional manufacturing on Candida albicans and Streptococcus mutans adhesion to oral splint resins. Standardized specimens of four 3D-printed, two milled, one thermoformed and one pressed splint resin were assessed for surface roughness by widefield confocal microscopy and for surface free energy by contact angle measurements. Specimens were incubated with C. albicans or S. mutans for two hours; a luminometric ATP assay was performed for the quantification of fungal and bacterial adhesion. Both one-way ANOVA with Tukey post hoc testing and Pearson correlation analysis were performed (p < 0.05) in order to relate manufacturing methods, surface roughness and surface free energy to microbial adhesion. Three-dimensional printing and milling were associated with increased adhesion of C. albicans compared to conventional thermoforming and pressing, while the S. mutans adhesion was not affected. Surface roughness and surface free energy showed no significant correlation with microbial adhesion. Increased fungal adhesion to oral splints manufactured by 3D printing or milling may be relevant for medically compromised patients with an enhanced risk for developing candidiasis.


1989 ◽  
Vol 50 (24) ◽  
pp. 3527-3534 ◽  
Author(s):  
P. Oswald ◽  
F. Melo ◽  
C. Germain

2011 ◽  
Vol 2 (2) ◽  
pp. 101-105
Author(s):  
L. Fazekas ◽  
Z. S. Tiba ◽  
G. Kalácska

Abstract The lubricant storing and releasing ability of the thermally sprayed surfaces plays an essential role in the proper operation of the components. In the case of porous sprayed surfaces the lubricant storing and releasing ability depends mainly on porosity and the surface energy (adhesion susceptibility). The adhesion ability can also be expressed indirectly with an index number that is by determining the surface free energy.


1989 ◽  
Vol 54 (12) ◽  
pp. 3171-3186 ◽  
Author(s):  
Jan Kloubek

The validity of the Fowkes theory for the interaction of dispersion forces at interfaces was inspected for the system water-aliphatic hydrocarbons with 5 to 16 C atoms. The obtained results lead to the conclusion that the hydrocarbon molecules cannot lie in a parallel position or be randomly arranged on the surface but that orientation of molecules increases there the ration of CH3 to CH2 groups with respect to that in the bulk. This ratio is changed at the interface with water so that the surface free energy of the hydrocarbon, γH, rises to a higher value, γ’H, which is effective in the interaction with water molecules. Not only the orientation of molecules depends on the adjoining phase and on the temperature but also the density of hydrocarbons on the surface of the liquid phase changes. It is lower than in the bulk and at the interface with water. Moreover, the volume occupied by the CH3 group increases on the surface more than that of the CH2 group. The dispersion component of the surface free energy of water, γdW = 19.09 mJ/m2, the non-dispersion component, γnW = 53.66 mJ/m2, and the surface free energies of the CH2 and CH3 groups, γ(CH2) = 32.94 mJ/m2 and γ(CH3) = 15.87 mJ/m2, were determined at 20 °C. The dependence of these values on the temperature in the range 15-40 °C was also evaluated.


2020 ◽  
Vol 7 (12) ◽  
pp. 3869-3876
Author(s):  
Kathryn M. Peruski ◽  
Brian A. Powell

Solubility of neptunium dioxide decreases as microstructure grain size increases, likely due to decreasing surface free energy and surface area.


2021 ◽  
pp. 002203452110181
Author(s):  
A.A. Balhaddad ◽  
I.M. Garcia ◽  
L. Mokeem ◽  
M.S. Ibrahim ◽  
F.M. Collares ◽  
...  

Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque control, enhanced biofilm accumulation, and cause gingival irritation. A potential material to restore such lesions should combine agents that interfere with bacterial biofilm development and respond to acidic conditions. Here, we explore the use of new bioresponsive bifunctional dental composites against mature microcosm biofilms derived from subgingival plaque samples. The designed formulations contain 2 bioactive agents: dimethylaminohexadecyl methacrylate (DMAHDM) at 3 to 5 wt.% and 20 wt.% nanosized amorphous calcium phosphate (NACP) in a base resin. Composites with no DMAHDM and NACP were used as controls. The newly formulated 5% DMAHDM–20% NACP composite was analyzed by micro-Raman spectroscopy and transmission electron microscopy. The wettability and surface-free energy were also assessed. The inhibitory effect on the in vitro biofilm growth and the 16S rRNA gene sequencing of survival bacterial colonies derived from the composites were analyzed. Whole-biofilm metabolic activity, polysaccharide production, and live/dead images of the biofilm grown over the composites complement the microbiological assays. Overall, the designed formulations had higher contact angles with water and lower surface-free energy compared to the commercial control. The DMAHDM-NACP composites significantly inhibited the growth of total microorganisms, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum by 3 to 5-log ( P < 0.001). For the colony isolates from control composites, the composition was typically dominated by the genera Veillonella, Fusobacterium, Streptococcus, Eikenella, and Leptotrichia, while Fusobacterium and Veillonella dominated the 5% DMAHDM–20% NACP composites. The DMAHDM-NACP composites contributed to over 80% of reduction in metabolic and polysaccharide activity. The suppression effect on plaque biofilms suggested that DMAHDM-NACP composites might be used as a bioactive material for cervical restorations. These results may propose an exciting path to prevent biofilm growth and improve dental composite restorations’ life span.


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