Abstract Micro-hardness is a fundamental property of prosthodontic restorative materials, as it affects their resistance to surface deformation, wear, and long-term clinical performance. This study aimed to compare the Vickers micro-hardness of three widely used CAD/CAM materials: lithium disilicate, monolithic zirconia, and multilayered zirconia. A total of 30 specimens (N = 30) were fabricated, with 10 samples allocated to each material group. Lithium disilicate specimens were prepared as rectangular plates (18 × 15 × 1 mm), whereas zirconia specimens—both monolithic and multilayered—were fabricated as discs (10 mm in diameter and 1.5 mm in thickness) following standardized CAD/CAM milling and sintering protocols. Vickers micro-hardness testing was conducted using a digital micro-hardness tester under material-specific conditions: a load of 1 kg and a dwell time of 10 s for lithium disilicate, and a load of 500 g with a 20 s dwell time for zirconia. Statistical analysis was performed using one-way ANOVA followed by Tukey’s post-hoc test, with the significance level set at p < 0.05. Significant differences in micro-hardness were identified among the three materials (p < 0.001). Monolithic zirconia demonstrated the highest mean hardness (680 ± 19 HV), followed by multilayered zirconia (623 ± 47 HV), while lithium disilicate exhibited the lowest values (553 ± 32 HV). Post-hoc analysis confirmed that all pairwise comparisons were statistically significant. The findings indicate that monolithic zirconia possesses superior micro-hardness compared to multilayered zirconia and lithium disilicate, supporting its suitability for high-stress clinical applications. Multilayered zirconia offers a balance between mechanical performance and esthetics, whereas lithium disilicate remains optimal for highly esthetic anterior restorations. These results provide clinicians with evidence-based guidance for selecting CAD/CAM materials in fixed prosthodontic rehabilitation. 

Background and objective :Helicobacter pylori [H.pylori] infection is one of the most common chronic bacterial infections worldwide especially in the developing countries. This bacterium is the cause of many diseases such as MALT lymphoma, gastritis, peptic ulcers, and stomach cancer. According to recent reports, H.pylori infection may increase the risk of colorectal cancer. The current study aimed at investigating the association of H. pylori infection and the risk of colorectal cancer and adenomatous polyps. Methods: The current study was conducted on 52 patients with colon cancer as the case group and 200 subjects without pathological finding (i e, polyps, neoplasms, or inflammatory diseases) as the control group. Blood samples were collected from the patients in order to assess the presence of anti-H. pylori infection antibodies by the serum titer levels of anti-H. pylori IgG antibodies were measured using enzyme-linked immunosorbent assay (ELISA) with commercial kit by (Dia.Pro Diagnostic Bioprobes-Italy). Results: This study demonstrates distinct associations between H.pylori infection markers and CRC risk. While IgG seropositivity showed a significant 2.16-fold increased CRC risk (p = 0.019). Conclusion: This research finding IgG seropositivity may serve as a broader risk marker.

Abstract:Abstract

Digital image processing is increasingly being used in a variety of industries, including food processing, medical science, particle technology, cement, and powder manufacturing. Medical image processing is a discipline in medical science that involves the use of technology to take images of the human body's interior in the least invasive way possible. As medical and biological sciences advance, imaging has become a more important discipline. One of the most useful programs is ImageJ, a public-domain Java image processing program inspired by NIH Image for the Macintosh. In this study, we demonstrated some, but not all, applications of ImageJ in the medical field and for medical and biological students that can be easily implemented in their institutions.  One of these applications was bacterial cell counting, in which a microscopic image of gram-stained bacterial cells was captured using a student's smartphone, treated with ImageJ, and the bacterial cells were easily counted automatically using ImageJ. The second application of ImageJ in this review was to calculate the antimicrobial zone of inhibition. We calculated the percentage of the inhibition zone for three different amoxicillin antibiotic brands using very simple steps. The third application of ImageJ was to analyze a CT scan brain images, and we were able to define the hemorrhage location. Finally, we demonstrated that this free software can estimate protein-protein colocalization. This technique is useful in many cell biological and physiological studies to demonstrate the relationship between pairs of biomolecules. In another example of co-localization, the researchers confirmed the SyGCaM2-mCherry sensor's presynaptic localization to hippocampal synapses, where it was co-localized with a bassoon (a presynaptic protein) in the stratum radiatum of area CA1. In general, ImageJ is a very useful, free program that can be used easily by specialized people and the beginner medical students.

The surface integrity of CAD/CAM restorative materials is critical for their esthetic and mechanical performance. Acidic challenges in the oral environment can degrade ceramic surfaces, increasing roughness and potentially compromising restoration longevity. This study aimed to evaluate and compare the effect of 4% acetic acid immersion on the surface roughness (Ra) of lithium disilicate glass-ceramic and hybrid ceramic (Vita Enamic) CAD/CAM restorative materials. A total of 40 rectangular specimens (18×15×1 mm) were fabricated, 10 per material per condition. Specimens were polished according to manufacturer protocols and immersed in 4% acetic acid (v/v) at 80∘C for 16 hours, following ISO 6872 standards. Surface roughness was measured using a Roughness Tester (PCE-RT 2000). Data were analyzed using independent t-tests, and effect sizes were calculated (Cohen’s d). Both materials exhibited significant increases in surface roughness after acid exposure. Lithium disilicate showed Ra values increasing from 0.0676±0.0187 µm to 0.5129±0.0912 µm (p<0.001, d=4.79). The hybrid ceramic exhibited a larger increase, from 0.2063±0.0568 µm to 1.4409±0.4951 µm (p<0.001, d=2.48). The hybrid material was therefore more susceptible to acid-induced degradation than lithium disilicate. Immersion in 4% acetic acid significantly deteriorates the surface of both lithium disilicate and hybrid ceramic, with hybrid ceramic showing greater roughness changes. Lithium disilicate may be preferred for patients at high risk of acidic challenges. These findings emphasize the importance of material selection and surface management to optimize restoration longevity.

Fracture toughness is a critical mechanical property influencing the clinical durability of prosthodontic materials, especially those used in high-stress posterior regions. Differences in composition, microstructure, and fabrication technologies can significantly affect resistance to crack propagation. This experimental study evaluated the fracture toughness of three prosthodontic material groups (n = 10 each). Standardized samples were prepared and tested using the Vickers indentation technique under controlled laboratory conditions. Descriptive statistics were calculated for each group, and a one-way analysis of variance (ANOVA) was performed to determine significant differences among the groups. Post-hoc pairwise comparisons were conducted using Tukey’s Honest Significant Difference (HSD) test. Statistically significant differences in fracture toughness were observed among the three groups (p < 0.001). Group II demonstrated the highest mean fracture toughness (5.39 ± 0.34 MPa·m^1/2), followed by Group III (4.34 ± 0.36 MPa·m1/2). Group I recorded the lowest mean value (2.82 ± 0.56 MPa·m1/2). Tukey’s post-hoc analysis confirmed that all pairwise comparisons were significant (p < 0.001), indicating that each material group exhibited distinct mechanical performance profiles. The findings show that the fracture toughness of prosthodontic materials vary significantly depending on their composition and manufacturing technology. Materials in Group II outperformed the other groups, suggesting greater suitability for clinical situations where high resistance to fracture is required. Further studies incorporating additional mechanical tests and long-term clinical evaluation are recommended to validate these results under functional oral conditions.