Comparison of the Surface Properties of 3D-printed Permanent Restorative Resins and Resin-based CAD/CAM Blocks.

OBJECTIVE: This study aimed to investigate the surface roughness, microhardness, and color changes of resin-based computer-aided design/computer-aided manufacturing (CAD/CAM) blocks and 3D-printed permanent resins in different beverages. METHODS AND MATERIALS: Resin-based CAD/CAM blocks (Cerasmart 270 and Grandio Blocs) and 3D-printed permanent restorative resins (Crowntec and Permanent Crown) were used in this study. A total of 96 specimens were prepared from CAD/CAM blocks and 3D-printed permanent resins. The initial surface roughness, microhardness, and shade value of the specimens were measured. Then, the specimens prepared from each material were divided into three subgroups (n=8) and immersed in tea, coffee, and distilled water for 30 days. After the specimens were immersed in the beverages, the surface roughness, microhardness, and tone values were measured again. The data were statistically analyzed using a two-way analysis of variance test (p<0.05). RESULTS: No statistically significant difference was found in the surface roughness values of the resin-based CAD/CAM blocks and 3D-printed resins (p<0.05). Resin-based CAD/CAM blocks showed statistically significantly higher microhardness than 3D-printed permanent resins (p<0.05). Although the color changes in 3D-printed resins in tea and coffee were similar to those in resin-based CAD/CAM blocks on the first and seventh days, more color changes appeared in the 3D-printed resins after 30 days. The surface roughness and microhardness values of the specimens submerged in tea, coffee, and distilled water showed no statistically significant changes (p<0.05). CONCLUSIONS: Although the surface roughness of 3D-printed permanent resins was similar to that of resin-based CAD/CAM blocks, they had a lower microhardness value. Moreover, 3D-printed permanent resins showed more color changes in tea and coffee.

COVID-19: booster(s) vs. hospitalization and Intensive Care Unit admission.

OBJECTIVE: As the pandemic continues, different vaccine protocols have been implemented to maintain the protection of vaccines and to provide protection against new variants. The aim of this study was to assess hospitalized patients' vaccination status and document the efficacy of boosters. PATIENTS AND METHODS: The patients that were hospitalized due to COVID-19 were enrolled from 28 hospitals in Turkey for five months from September 2021. 5,331 confirmed COVID-19 patients from collaborating centers were randomly enrolled to understand/estimate the distribution of vaccination status in hospitalized patients and to compare the efficacy of vaccination/booster protocols. RESULTS: 2,779 men and 2,552 women of which 2,408 (45.2%) were admitted to Intensive Care Units participated in this study. It was found that the highest risk reduction for all age groups was found in groups that received 4 doses. Four doses of vaccination for every 3.7 people under 50 years of age, for every 5.7 people in the 50-64 age group, and for every 4.3 people over 65 years of age will prevent 1 patient from being admitted to intensive care. Regardless of the type of vaccine, it was found that the risk of ICU hospitalization decreased in those who were vaccinated compared to those who were not vaccinated. Regardless of the type of vaccine, the ICU risk was found to decrease 1.25-fold in those who received 1 or 2 doses of vaccine, 1.18-fold in those who received 3 doses, and 3.26-fold in those who received 4 doses. CONCLUSIONS: The results suggested that the addition of a fourth dose is more effective in preventing intensive unit care even in disadvantaged groups.

Resistance of Single-shade Composites to Discoloration.

The aim of this study was to examine the color change of single-shade resin composites, which can be used for all tooth shades. In this study, samples were prepared using resin composites with single-shade (Omnichroma, Vitra Unique) and multishade composite systems (G-aenial A'Chord, Clearfil Majesty ES-2 Premium). The initial color values were measured with a spectrophotometer. Then, samples were kept in wine, coffee, black tea, and distilled water and color measurements were made after days 1, 7, and 30. Color change (ΔE00) and whiteness index (WID) values were statistically analyzed using a one-way analysis of variance (ANOVA) test (α=0.05). Single-shade resin composites showed more color change from wine, coffee, and black tea than multishade resin composites (p<0.001). Single-shade composites have a greater discoloration potential. Single-shade resin composites may show more color change from beverages than multishade resin composites, which may negatively affect clinical success.

Evaluation of the cytotoxicity of contemporary glass-ionomer cements on mouse fibroblasts and human dental pulp cells.

PURPOSE: This study aimed to evaluate the cytotoxic effects of different types of contemporary GICs on human dental pulp cell (hDPCs) and mouse fibroblast (L929) cultures. METHODS: Three high-viscosity GICs (HVGIC; GC Equia Forte, Riva Self Cure, IonoStar Plus), three resin-modified GICs (RMGIC; Photac Fil, Riva Light Cure, Ionolux), and a metal-reinforced GIC (MRGIC; Riva Silver) were investigated. Twelve disc-shaped specimens of each material were prepared and stored in Dulbecco's modified Eagle medium (DMEM). L929 fibroblasts and DPCs were then cultured in 96-well plates. Uncultured DMEM was used as a negative control. Mitochondrial dehydrogenase activity (MTT) assays were performed to detect cell viability after 24, 48, and 72 h. Data were analysed using Mann-Whitney U and Friedman tests followed by a Bonferroni-corrected Wilcoxon signed rank test, with the statistical significance set at P < 0.05. RESULTS: Toxicity levels varied between the cell-culture systems. MTT assays of L929 cells showed significant differences in percentages of viable cells, as follows: Riva Self Cure = Riva Silver > GC Equia Forte > IonoStar Plus = Riva Light Cure = Photac Fil > Ionolux. MTT assays of DPCs showed the percentages of viable cells to be significantly lower for the Ionolux group when compared to the other GICs, which did not differ significantly from one another. With the exception of Ionolux, none of the other GICs tested showed any toxicity, and in fact, they all induced cell proliferation (> 100% cell viability). CONCLUSIONS: Although the degree of toxicity varied between the two cell-culture systems investigated, all the GICs tested, with the exception of Ionolux, performed favorably with regard to cytotoxicity (> 100% cell viability in both cell systems).