The topography of implant surfaces influences the interaction relationship between material and bacteria. The aim of this work was to characterize a novel 3D titanium surface, produced using Selective Laser Sintering (SLS), and to compare the bacterial interaction with machined and double acid etching (DAE) discs. The surface was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and Energy Dispersive X-ray Spectrometry (EDX). The wettability was measured using the sessile method. The microbiological investigation consisted in the cultivation of a bacterial pioneer, Streptococcus oralis, on titanium surfaces, previously covered by human saliva in order to form the acquired pellicle. Then, colony forming units (CFUs), biofilm biomass quantification, analyses of viable and dead cells, and SEM observation were determined after 24 h of S. oralis biofilm formation on the different discs. A significantly higher nano-roughness with respect to the other two groups characterized the novel 3D surface, but the wettability was similar to that of machined samples. The microbiological assays demonstrated that the 3D discs reported significantly lower values of CFUs and biofilm biomass with respect to machined surfaces; however, no significant differences were found with the DAE surfaces. The live/dead staining confirmed the lower percentage of living cells on DAE and 3D surfaces compared with the machined. This novel 3D surface produced by SLS presented a high antiadhesive and antibiofilm activity.
Purpose: The present study was conducted to determine oxidative stress and cell viability after contact with resin composites polymerized for different times. Methods: Disk-shaped specimens of Admira Fusion, Ceram X One Universal, Solare x and Filtek Z550 (n = 12) were prepared, and two subgroups with polymerization times of 20 and 40 s were employed. The specimens were incubated with mouse fibroblast cells for 48 and 72 h, and changes in reactive oxygen species (ROS) production and cellular viability were determined by an assay with a cell-permeable fluorescent dye, 2',7'-dichlorodihydrofluorescein diacetate (H 2 DCF-DA), and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, respectively. Results: At 72 h, ROS production in the presence of Admira Fusion polymerized for 40 s was reduced relative to that in the presence of Admira Fusion polymerized for 20 s (P < 0.05). Cell viability was maximal in the Admira Fusion and Solare x groups and there was no difference relative to the control group at 48 h. Cell viability was higher in the Admira Fusion and Solare x groups polymerized for 40 s than for the same materials polymerized for 20 s at 72 h (P < 0.05). Conclusion:Extension of the polymerizaton time has a material-specific effect and may be used as a strategy to increase the biocompability of resin composites.
The aim of this study is to investigate the effect of toothbrushing and paste repolishing on the colour restitution of long‐term coffee discoloured prefabricated and direct resin composites. One prefabricated (Componeer‐Coltène) and three direct resin composites (Brilliant Ever Glow‐Coltène, Essentia‐GC, Harmonize‐Kerr) were tested. Componeer samples were prepared with and without polishing while the other groups were all polished. After baseline colour‐measurement, the specimens were immersed in coffee for 3‐month and colour‐measurement was repeated, then a simulation of 1‐year of toothbrushing (Toothbrush Simulation ZM‐3.4‐SD Mechatronics) with Pro‐Expert Professional Protection‐Ipana, 3D White Luxe Perfection‐Ipana, and White Ruscello‐GC toothpaste was performed. Colour‐changes (ΔE) after toothbrushing and repolishing with polishing paste (Enamelize, Cosmodent) were calculated. The discolouration occurred after prolonged exposure to a coffee solution was above the clinically acceptable level of ΔE = 2 in all groups, except Componeer polished group. The lowest discoloured group was Componeer polished (ΔE = 1.66 ± 0.32) while the highest was Essentia group (ΔE = 4.30 ± 0.48). The samples toothbrushed with White Ruscello exhibited the greatest colour restitution (ΔE = 2.06 ± 0.75) (P < .05). After paste repolishing, slight colour restitution was observed among all the groups, but the differences between them remained the same as after the toothbrushing procedure. Prolonged exposure to coffee solution affects the colour of the resin composites and noninvasive methods can provide colour restitution below the critical value for visual perception (ΔE = 3.3). Noninvasive procedures such as toothbrushing with a whitening toothpaste or repolishing with a polishing paste may ensure the colour restitution of direct resin composite restorations until a clinically acceptable level.
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