Sol–Gel Synthesis and Characterization of YSZ Nanofillers for Dental Cements at Different Temperatures

From MDPI via Jisc Publications RouterHistory: accepted 2021-10-26, pub-electronic 2021-10-29Publication status: PublishedFunder: The project is co-financed by Greece and the EuropeanUnion (European Social Fund-ESF) by the Operational Program Human Resources Development,Education and Lifelong Learning 2014–2020.; Grant(s): MIS5047876Background: Yttria-stabilized zirconia nanoparticles can be applied as fillers to improve the mechanical and antibacterial properties of luting cement. The aim of this study was to synthesize yttria-stabilized zirconia nanoparticles by the sol–gel method and to investigate their composition, structure, morphology and biological properties. Methods: Nanopowders of ZrO2 7 wt% Y2O3 (nY-ZrO) were synthesized by the sol–gel method and were sintered at three different temperatures: 800, 1000 and 1200 °C, and their composition, size and morphology were investigated. The biocompatibility was investigated with human gingival fibroblasts (hGFs), while reactive oxygen species (ROS) production was evaluated through fluorescence analysis. Results: All synthesized materials were composed of tetragonal zirconia, while nanopowders sintered at 800 °C and 1000 °C additionally contained 5 and 20 wt% of the cubic phase. By increasing the calcination temperature, the crystalline size of the nanoparticles increased from 12.1 nm for nY-ZrO800 to 47.2 nm for nY-ZrO1200. Nano-sized particles with good dispersion and low agglomeration were received. Cell culture studies with human gingival fibroblasts verified the nanopowders’ biocompatibility and their ROS scavenging activity. Conclusions: the obtained sol–gel derived nanopowders showed suitable properties to be potentially used as nanofillers for dental luting cement

Zirconia bond strength durability following artificial aging: A systematic review and meta-analysis of in vitro studies

The present study systematically reviewed the literature regarding the bond strength durability of zirconia ceramics to resin-based luting cements after application of different bonding protocols and aging conditions. Electronic searches in PubMed, Scopus, and Web of Science databases were performed for relevant literature published between January 1st 2015 and November 15th 2022. Ninety-three (93) English language in-vitro studies were included. The percentage of the mean bond strength change was recorded prior to and after artificial aging, and the weighted mean values and 95% confidence intervals were calculated. Bonding protocols were classified based on the combination of MDP/non-MDP containing cement/primer and surface pretreatment, as well as the level of artificial aging performed. Alumina sandblasting (SA) was identified as the most frequently used surface pre-treatment while an insufficient number of studies was identified for each category of alternative surface treatments. The combination of MDP cement with tribochemical silica coating (TSC) or SA yielded more durable results after aging, while the application of SA and TSC improved bond durability when a non-MDP cement and a non-MDP primer were used. TSC may lead to increased bond durability compared to SA, whereas MDP cements may act similarly when combined with SA or TSC

Zirconia Nanoparticles as Reinforcing Agents for Contemporary Dental Luting Cements: Physicochemical Properties and Shear Bond Strength to Monolithic Zirconia

Nanofillers in resin materials can improve their mechanical and physicochemical properties. The present work investigated the effects of zirconia nanoparticles (NPs) as fillers in commercial dental luting cements. Two dual-cured self-adhesive composites and one resin modified glass ionomer (RMGI) luting cement were employed. Film thickness (FT), flexural strength (FS), water sorption (Wsp), and shear bond strength (SBS) to monolithic zirconia were evaluated according to ISO 16506:2017 and ISO 9917-2:2017, whereas polymerization progress was evaluated with FTIR. Photopolymerization resulted in double the values of DC%. The addition of 1% wt NPs does not significantly influence polymerization, however, greater amounts do not promote crosslinking. The sorption behavior and the mechanical performance of the composites were not affected, while the film thickness increased in all luting agents, within the acceptable limits. Thermocycling (TC) resulted in a deteriorating effect on all composites. The addition of NPs significantly improved the mechanical properties of the RMGI cement only, without negatively affecting the other cements. Adhesive primer increased the initial SBS significantly, however after TC, its application was only beneficial for RMGI. The MDP containing luting cement showed higher SBS compared to the RMGI and 4-META luting agents. Future commercial adhesives containing zirconia nanoparticles could provide cements with improved mechanical properties

Early diagnosis of enteromyxosis in intensively reared sharpsnout seabream, Diplodus puntazzo

Myxozoans are metazoan parasites which are highly pathogenic in commercially important fish, particularly in aquaculture. Enteromyxosis is an economically significant disease caused by the myxosporean parasite Enteromyxum leei. Presently, early diagnosis of enteromyxosis in sharpsnout seabream was achieved by monitoring fish on a time-scale scheduled basis in combination with a validated molecular diagnostic technique. Two different successive fish batches of a commercial fish farm were monitored starting from the first month of on-growing in sea cages until fish reached commercial size. Fish weight and water temperature differentially ranged between them. E. leei detection was performed both by classical microscopic observation of fresh smears and by quantitative polymerase chain reaction (qPCR) while prevalence, mean intensity and mortality rate were calculated. In total, 520 fish were screened; 320 from the first batch and 200 from the second one. Parasitosis illustrated a seasonal occurrence pattern (spring and summer). When qPCR was used as a diagnostic method, enteromyxosis was diagnosed earlier with more increased prevalence compared to the microscopic observation. In this case, the parasite was detected at the lowest water temperature that has ever been recorded (14.7 degrees C), during the first month of on-growing in sea cages. The two-factor combination of water temperature and fish weight proved to be the most significant factor that could determine the emergence and development of parasitosis and smaller fish proved to be more susceptible. Mortality was influenced by both prevalence and intensity of parasitosis. An earlier diagnosis and identification of all developmental stages of the parasite throughout its life cycle was verified with qPCR, significantly before any outbreak occurred. The latter could become a key diagnostic tool for the control of enteromyxosis, allowing stakeholders and fish farmers to adopt all necessary precautionary measures minimizing economic loss in sharpsnout seabream intensive farming