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Influence of Different Polishing Methods on Surface Roughness and Microhardness of Dental Composites

Mierzejewska Żaneta A., Łukaszuk Kamila, Choromańska Magdalena, Zalewska Anna, Borys Jan, Antonowicz Bożena, Kulesza Ewa

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 1

268--279

EN

The surface roughness and microhardness of dental composites greatly affects the durability of restorations. To evaluate the effect of three different polishing systems (Sof-Lex, Enhance+PoGo, Kenda) on the surface roughness and microhardness of microhybrid (Herculite XRV, Filtek Z250 and Charisma Flow) and nanohybrid (Herculite XRV Ultra, Filtek Z550 and Charisma Bulk Flow) composites resin used for dental fillings. Six different composites were used in the study. From each material, 40 cylinder-shaped samples were made. All samples were polymerized and polished using three different methods. To evaluate surface roughness a confocal laser microscope was used, and microhardness was determined using a universal Vickers hardness tester.The data were analysed using the one-way ANOVA test at a significance level of 0.05 for both tests. The smoothest surfaces in all groups of composites were obtained for control samples. Also in all groups of composite samples no statistically significant differences were found between the Sof-Lex and Enhance+PoGo. The measurement of surface roughness obtained for the Kenda system showed significantly lower values than for the other two methods. The surfaces of the control samples showed statistically significantly lower microhardness values compared to all polishing systems for all six tested resin composites, additionally no statistically significant differences were found between all finishing and polishing methods. Regardless of the finishing and polishing method used, the lowest microhardness values among microhybrid materials were found for Charisma Flow, while among nanohybrid materials the lowest values were obtained for Herculite HRV Ultra. Finishing and polishing increases the microhardness of microhybrid and nanohybrid composite resin. The use of Kenda three step polishing system resulted in smoother surface for all tested composite materials compared to the Sof-Lex and Enhance+PoGo systems, while the finishing and polishing method had little effect on the microhardness of the surface.

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Influence of silver-containing filler on antibacterial properties of experimental resin composites against Enterococcus faecalis

Adeeb S., Adeeb S., Chladek G., Pakieła W., Mertas A.

Journal of Achievements in Materials and Manufacturing Engineering

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2021

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Vol. 109, nr 2

59--67

EN

Purpose: The aim of the presented work was to investigate the impact of the S-P introduction into resin-based composites on their effectiveness against Enterococcus faecalis (E. faecalis). Design/methodology/approach: Seven experimental composites based on typical matrix were developed. Six of them contained a filler with antimicrobial properties (silver sodium hydrogen zirconium phosphate, S-P), while the control material contained only common reinforcement fillers. The materials were characterized in terms of the dispersion of the extender in the matrix and then subjected to microbiological tests. The efficiency in the reduction of E. faecalis in the microenvironment was tested. Findings: The composites show a satisfactory distribution of fillers and a high initial reduction of bacteria colonies for the tested strain of E. faecalis. The reduction in bacteria colonies achieved for S-P concentrations from 7% to 13% was similar (median value from 99.8 to 99.9%, when for control material and compound with 1% S-P the number of colonies increased compared to positive control. Research limitations/implications: Laboratory test results may differ from in vivo test performance. In addition, there are many models for conducting laboratory antimicrobial efficacy studies, the results of which are also varied. The cytotoxic tests, long-term investigations and in vivo experiments need to be performed in future experiments. Practical implications: E. faecalis is a Gram-positive bacterium that is commonly detected in persistent endodontic infections and may enter the root canal through the coronal part. Development of composites with antimicrobial properties against this bacterium is as important as obtaining efficacy against cariogenic bacteria. Originality/value: The antimicrobial effectiveness against E. faecalis of experimental composites with submicrometer-sized particles of S-P was not investigated until now.

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Recycling of Electrical Insulators, by their Secondary Use, as Substitutes for Mineral Aggregates in Artificial Composites Based on Orthophthalic Polyester Resins

Zegardło Bartosz

Journal of Ecological Engineering

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2020

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Vol. 21, nr 7

241--248

EN

This paper is a continuation of the research work on the reuse of worn-out electric insulators. The aim of this analysis was to check the possibility of using this waste matter in composites in which the bonding phase is made of orthophthalic polyester resins. In order to test the thesis, a transparent resin composite was designed, which contained the recycled aggregates from worn-out electrical insulators. Aggregate with a grain size of 1–2 mm was prepared from the elements obtained during the renovation works. Unsaturated orthophthalmic polyester resin was used as binder. The initiator – methyl ethyl ketone peroxide – was used to cure the resin. Aluminum cement was used as a fine filling phase. A synthetic stone was produced from the substrates prepared in this way, which was subjected to the basic tests carried out for concretes used in construction. The density of the composite, absorbability, and strength parameters such as flexural tensile strength and compressive strength were examined. The results showed that from the described components it is possible to obtain a resin composite which, apart from interesting aesthetics, meets the requirements for construction materials used in the building industry.

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Effects of Different Inorganic Fillers on Mechanical Properties and Degree of Conversion of Dental Resin Composites

Stencel R., Pakieła W., Barszczewska-Rybarek I., Żmudzki J., Kasperski J., Chladek G.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 3

1361--1369

EN

The aim of the study was to evaluate the influence of different fillers on the chosen functional properties of experimental composites based on typical polymeric matrix, in order to understand the effect of different fillers on their properties and to develop a simple base composite for further investigations with experimental fillers, e.g. with antimicrobial properties. Previous experiments have been usually based on commercially available composites of unknown composition or compilation of monomers, without reinforcing fillers. Scanning electron microscopy was used to investigate the quality of fillers’ dispersion, which was satisfying. Results showed significant differences between materials’ diametral tensile strength (p = 0.0019), compressive strength (p < 0.0001), Vickers microhardness (p < 0.0001), flexural modules (p = 0.0018), and the degree of conversion (p < 0.0001), but flexural strength was not significantly different (p = 0.0583). Investigations indicated that no filler type had an especially positive impact on the mechanical properties, but reinforcement effect was achieved by proper compilation of silica nanofiller and variable glass fillers. Nanofiller decreased the degree of conversion.