Search Results (31)

Background/Objectives: This study aimed to assess the long-term clinical performance of full-arch fixed restorations made of fiber-reinforced composite (FRC) supported by four ultra-short implants (4.0 × 5.0 mm) in patients with edentulous, atrophic mandibles. Methods: Ten patients were treated at Sapienza University of Rome and monitored over a 10-year period. Each case involved the placement of four plateau-design implants with a pure conometric connection and a calcium phosphate-treated surface. The final prostheses were fabricated using CAD/CAM-milled Trinia^® fiber-reinforced composite frameworks. Clinical parameters included implant and prosthesis survival, marginal bone level (MBL), peri-implant probing depth (PPD), and patient-reported outcome measures (PROMs). Results: Implant and prosthesis survival reached 100% over the 10-year follow-up. MBL data showed a minor bone gain of approximately 0.11 mm per 5 years (p < 0.0001). PPD remained stable under 3 mm, with a minimal increase of 0.16 mm over the same period (p < 0.0001). PROMs reflected sustained high patient satisfaction. No technical complications, such as chipping or framework fracture, were observed. Conclusions: Rehabilitation of the edentulous mandible with ultra-short implants and metal-free FRC prostheses proved to be a minimally invasive and long-lasting treatment option. The 10-year follow-up confirmed excellent implant and prosthetic outcomes, favorable peri-implant tissue health, and strong patient satisfaction. Nonetheless, further studies with larger sample sizes are needed to confirm these encouraging results and strengthen the clinical evidence. Full article

The church of Saint Felix in Girona (Spain) is crowned by an octagonal bell tower with a stone pinnacle at each corner. It was built using dry-joint stone masonry, a technique that involves laying stones in a precise pattern to create a solid and durable structure. In order to strengthen the connection between the stone blocks of the pinnacles, a wooden bar was placed through a central hole carved in the stone structure. Today, the inner structure has completely disappeared. During maintenance and repair work, it was decided to restore the functionality of the disappeared reinforcement by installing a titanium bar in its place. Due to the uncertainty associated with the pinnacle’s behaviour and the lack of both, a proper numerical model of the monument, and an extensive characterization of the materials, a strategy based on multiple approaches was designed. The proposed strategy was based on combining numerical and experimental models, the final objective being to determine the length and mechanical properties of the metallic inclusion, considering the effects of gravity, wind, and seismic forces. A scale model of the pinnacle was evaluated in laboratory conditions. The results were used to calibrate a numerical model representing the scale specimen. After calibration, the results were extrapolated to a full-scale numerical model. The experimental and numerical results showed that the pinnacles needed to be reinforced along their entire height. The tensile stresses cause by wind and seismic forces at different levels, could not be compensated without the contribution of the titanium bar inserted into the pinnacle. Full article

This study investigates structural integrity and proposes retrofitting solutions for the historical two-storey school building in Thrapsano, Crete, severely impacted by the September 2021 earthquake. An extensive methodology was adopted, incorporating field surveys, material characterization, finite element modeling, and experimental analysis. The assessment is focused on identifying structural damage, such as cracking and delamination in masonry walls, and evaluating the dynamic and static performance of the load-bearing system under seismic loads. Key interventions include grouting for masonry reinforcement, replacement of mortar with compatible materials, stitching of cracks, and the addition of reinforced concrete and metallic tie elements to enhance diaphragm action. Advanced numerical simulations, validated through experimental data, were employed to model the pre- and post-retrofit behavior of the structure. The proposed retrofitting measures align with Eurocodes 6 and 8, and the Greek code for masonry structures (KADET), aiming to restore the structural stability and improve seismic resilience while respecting the building’s historical significance. The results from the finite element analysis confirm the effectiveness of the interventions in reducing tensile stresses and improving load redistribution, ensuring compliance with modern safety standards. This case study offers a framework for the seismic retrofitting of heritage structures in a similar context. Full article

Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder characterized by metabolic dysregulation, oxidative stress, amyloid-β (Aβ) aggregation, metal dyshomeostasis, and mitochondrial dysfunction. Current treatments provide only symptomatic relief, highlighting the need for novel therapeutic strategies. This study investigates the metabolic effects of the alkaloids galantamine (GAL) and lycorine (LYC) in differentiated SH-SY5Y neuroblastoma cells, an established in vitro model for AD, which acquire a neuronal phenotype upon differentiation. Using untargeted and targeted NMR-based metabolomics combined with multivariate statistical analysis, we analyzed extracellular metabolic profiles under basal conditions and following Aβ42 exposure, both in the presence and absence of GAL and LYC. Our findings reveal distinct metabolic responses to Aβ toxicity, with significant alterations in pyruvate and glutamine metabolism. Both GAL and LYC contributed to the restoration of glutamine and lysine homeostasis, but LYC had a more pronounced effect, better sustaining cellular energy balance and mitochondrial function. Unlike LYC, GAL treatment was associated with pyruvate accumulation, highlighting a distinct metabolic response between the two compounds. These variations may reflect distinct mechanisms of action, potentially influencing their therapeutic roles in counteracting Aβ-induced toxicity. This study highlights the value of metabolic profiling for assessing neuroprotective agents and reinforces the potential of natural alkaloids in this context. Full article

This study presents the development and evaluation of an innovative modular ecological transition zone system for riparian restoration. Through systematic optimization, we developed a C25-grade ecological concrete module (100 mm × 100 mm × 100 mm) with a specialized cavity design (φ61 mm × H60 mm) that achieves optimal balance between structural integrity (20–30 MPa compressive strength) and environmental functionality (>15% porosity, >1 × 10⁻⁴ cm s⁻¹ permeability). The module incorporates precisely calibrated proportions of cement (378 kg m⁻³), reinforcing agent (12 kg m⁻³), aggregate (1650 kg m⁻³), and water (137 L m⁻³), creating a robust platform for environmental remediation. The system was evaluated at two scales: module-scale experiments in 25 L containers (833:1 mL g⁻¹ ratio) and kinetic studies (10:1 mL g⁻¹ ratio), revealing a sophisticated three-phase removal process. The initial rapid surface adsorption phase (0–4 h) achieved removal rates of 0.28–0.42 mg g⁻¹ h⁻¹, followed by pore diffusion (4–24 h) and chemical fixation phases, with removal patterns effectively modeled using a modified pseudo-second-order equation. The system demonstrated exceptional heavy metal removal capabilities across varying concentration ranges, achieving removal efficiencies of 95.6% for Pb²⁺ ions, 92.3% for Cd²⁺ ions, 84.2% for Cr³⁺ ions, 89.7% for Cu²⁺ ions, and 84.8% for Zn²⁺ ions under optimal conditions. Performance remained robust across two orders of magnitude in concentration ranges, with removal efficiencies maintaining above 80% at both experimental scales. The modular design’s cost-effectiveness is demonstrated through material costs of USD 45–60 m⁻³, with operational costs 40–60% lower than conventional systems. This research provides a practical, cost-effective solution for riparian zone restoration, combining structural durability with efficient pollutant removal capabilities while maintaining consistent performance across varying environmental conditions. Full article

Objective: This study aims to evaluate the influence of pontic length and design on the fracture resistance of zirconia fixed dental prostheses (FDPs). By assessing different span lengths under controlled mechanical loading conditions, the research seeks to provide insights into optimizing the structural integrity of zirconia dental bridges. Materials and Methods: A total of 20 zirconia bridges were fabricated and tested in vitro. Ten bridges were designed to replace a single missing molar (tooth 46), with a pontic span of 11 mm, while the remaining ten were crafted for two missing teeth (35 and 36), featuring a longer pontic span of 17 mm. The zirconia frameworks were milled using the Wieland Zenotec^® Select Hybrid system and cemented onto metal abutments with Voco Meron Plus QM resin-reinforced glass ionomer cement. The specimens were subjected to occlusal loading using a ZwickRoell ProLine Z005 testing machine at a crosshead speed of 1 mm/min until fracture occurred. Results: The mechanical testing revealed a significant correlation between pontic length and fracture resistance. The mean fracture resistance for three-unit bridges (single pontic) was 3703 N, whereas four-unit bridges (double pontic) exhibited a significantly lower resistance of 1713 N. These findings indicate that increased span length reduces the fracture resistance of zirconia restorations due to higher stress accumulation and reduced rigidity. Conclusions: This study underscores the importance of pontic length and design in determining the fracture resistance of zirconia restorations. Shorter spans exhibit greater structural stability, reinforcing the need for careful treatment planning when designing multi-unit zirconia bridges. By optimizing bridge parameters, clinicians can improve clinical outcomes and extend the longevity of zirconia prostheses in restorative dentistry. Full article

Introduction: Arthroscopic Bankart repair (ABR) is associated with an increased failure rate over time. The Recenter implant, a metal block, is designed to reinforce capsulolabral repair. The aim of this study was to evaluate whether the addition of the Recenter implant to ABR reduces the rate of recurrence in patients with glenohumeral anterior instability. Materials and Methods: This was a retrospective, multicentric case–control study focusing on patients surgically treated for anterior shoulder instability from February 2012 to November 2019. This study compared patients undergoing ABR augmented with the “Recenter” implant (augmented ABR group) against those receiving traditional ABR. Primary outcomes measured included recurrence rates. Secondary outcome measures included functional scores (Walch–Duplay and the subjective shoulder test [SST], the auto Rowe score, satisfaction, pain, and the presence or absence of subjective subluxation and apprehension), return to sports, the range of motion, as well as other complications. Results: Thirty-two patients with augmented ABR were compared to forty-eight patients in the traditional ABR group, with mean follow-up periods of 5.2 ± 1.3 years and 6.1 ± 1.5 years, respectively. Three patients (9.4%) experienced recurrence in the “Recenter” group, versus eight (16.7%) in the other group (p > 0.05). The Walch–Duplay score was 70.2 ± 8.2 in the “Recenter” group and 64.2 ± 8 in the control group (p > 0.05). The SST score out of 100 was, respectively, 84.6 ± 6 and 81.5 ± 5.5 (p = 0.05). There were no early complications in the implant group. No statistically significant differences were observed between the two groups for the other outcomes. Conclusions: ABR safely restores shoulder stability in selected patients with subcritical glenoid bone deficiency. However, the addition of the Recenter metal implant did not improve outcomes compared to traditional Bankart repair and introduced presumed significant surgical time, technical challenges, and additional costs. Full article

Polybenzoxazines (PBzs), a class of high-performance thermosetting polymers, have gained significant attention for their exceptional thermal stability, mechanical properties, and chemical resistance, making them ideal for aerospace, electronics, and biomedical applications. Recent advancements emphasize their antimicrobial potential, attributed to unique structural properties and the ability to incorporate bio-active functional groups. This review highlights the synthesis, antimicrobial mechanisms, and applications of PBzs and their bio-based derivatives, focusing on sustainable materials science. PBzs demonstrate antimicrobial efficacy through mechanisms such as hydrophobic surface interactions and reactive functional group formation, preventing microbial adhesion and biofilm development. The incorporation of functional groups like amines, quaternary ammonium salts, and phenolic moieties disrupts microbial processes, enhancing antimicrobial action. Modifications with metal nanoparticles, organic agents, or natural bio-actives further augment these properties. Notable bio-based benzoxazines include derivatives synthesized from renewable resources like curcumin, vanillin, and eugenol, which exhibit substantial antimicrobial activity and environmental friendliness. Hybrid PBzs, combining natural polymers like chitosan or cellulose, have shown improved antimicrobial properties and mechanical performance. For instance, chitosan-PBz composites significantly inhibit microbial growth, while cellulose blends enhance film-forming capabilities and thermal stability. PBz nanocomposites, incorporating materials like silver nanoparticles, present advanced applications in biomedical and marine industries. Examples include zirconia-reinforced composites for dental restoration and urushiol-based PBzs for eco-friendly antifouling solutions. The ability to customize PBz properties through molecular design, combined with their inherent advantages such as flame retardancy, low water absorption, and excellent mechanical strength, positions them as versatile materials for diverse industrial and medical applications. This comprehensive review underscores the transformative potential of PBzs in addressing global challenges in antimicrobial material science, offering sustainable and multifunctional solutions for advanced applications. Full article

This comprehensive review explores the biological functions of Perilla frutescens seed proteins and peptides, highlighting their significant potential for health and therapeutic applications. This review delves into the mechanisms through which perilla peptides combat oxidative stress and protect cells from oxidative damage, encompassing free radical scavenging, metal chelating, in vivo antioxidant, and cytoprotective activities. Perilla peptides exhibit robust anti-aging properties by activating the Nrf2 pathway, enhancing cellular antioxidant capacity, and supporting skin health through the promotion of keratinocyte growth, maintenance of collagen integrity, and reduction in senescent cells. Additionally, they demonstrate antidiabetic activity by inhibiting α-amylase and α-glucosidase. The cardioprotective effects of perilla peptides are underscored by ACE-inhibitory activities and combat oxidative stress through enhanced antioxidant defenses. Further, perilla peptides contribute to improved gut health by enhancing beneficial gut flora and reinforcing intestinal barriers. In liver, kidney, and testicular health, they reduce oxidative stress and apoptotic damage while normalizing electrolyte levels and protecting against cyclophosphamide-induced reproductive and endocrine disruptions by restoring hormone synthesis. Promising anticancer potential is also demonstrated by perilla peptides through the inhibition of key cancer cell lines, alongside their anti-inflammatory and immunomodulating activities. Their anti-fatigue effects enhance exercise performance and muscle function, while perilla seed peptide nanoparticles show potential for targeted drug delivery. The diverse applications of perilla peptides support their potential as functional food additives and therapeutic agents. Full article

Rivers are not only a vital part of the Earth’s water cycle but also sources and sinks for greenhouse gases (GHGs), exerting a significant influence on the global carbon budget. Rapid urbanization and intense human activities lead to water pollution and river habitat degradation, thereby affecting riverine greenhouse gas (GHG) emissions indirectly. Artificial management and restoration measures taken for rivers further increase the uncertainty of GHG emissions from rivers. In the context of carbon neutrality goals, research on GHG emissions from rivers has gradually become a hot topic. However, there is a scarcity of collective and comparative studies on the spatiotemporal patterns and mechanisms of riverine GHG emissions, especially a lack of summaries exploring the impacts of pollution and restoration on GHG emissions from rivers. This work systematically reviews recent studies concerning the emissions of CO₂, CH₄, and N₂O from rivers, with a particular focus on the characteristics and driving factors. Results have shown that riverine GHG emissions exhibit significant spatiotemporal heterogeneity. Besides hydrological factors such as wind speed, flow velocity, rainfall, and water level, large amounts of pollutants entering rivers strongly affect the production and emission of GHGs, since nutrients, organic matter, heavy metals, microplastics, and antibiotics can alter the biogeochemical processes in river ecosystems. Remediation measures can reduce water pollution levels, but some measures may further increase the emission of GHGs from rivers. This work emphasizes the need for conducting in-depth research on the synergies between treating river pollution and reducing riverine GHG emissions. It also proposes to reinforce the monitoring of GHGs and construct emission databases of rivers for sustainable watershed management. Full article

Background: Dental caries is one of the most prevalent dental illnesses in children. Untreated severe caries can damage teeth, requiring pulpotomy to save them. Objective: To evaluate the clinical success rate of treatments involving pulpotomies + IRM (Intermediate Restorative Material, composed of reinforced zinc oxide–eugenol polymers) + preformed metal crowns (PMCs) in primary teeth of children treated at a public university in Mexico. Materials and Methods: A cross-sectional ambispective study was conducted on children aged 10 years or younger, treated at a public university in Mexico. A total of 1281 medical records from February 2018 to June 2023 were reviewed, yielding a sample of 199 children treated with pulpotomy + IRM + PMC. Information was collected via telephone interviews with parents/caregivers to inquire about any symptoms following the pulpotomy and metal crown treatments. Success was defined as the absence of pain, inflammation, or infection. Results: During the study period, the number of teeth treated with pulpotomy + IRM + PMC was 414, with follow-ups ranging from 6 to 69 months. Most participants were girls (54.3%), while 45.7% were boys. Out of the 167 pulpotomy + IRM + PMC treatments included in the study, the clinical success rate was 98.2%. Conclusions: The clinical success rate of primary teeth treated with pulpotomy + IRM + PMCs was high, close to 100%, based on evidence and symptom reports from parents/caregivers. It would be beneficial to implement its use in public health institutions in countries such as Mexico. Full article

This study evaluates the mechanical properties of materials used in the post-endodontic restoration of root-treated teeth and examines their performance under stress to provide insights for material selection in clinical applications. Particular attention is given to zirconium oxide, which demonstrates promising characteristics due to its esthetic color and favorable material properties, positioning it as a potential material for future use in post-endodontic treatments. Three materials—prefabricated quartz fiber-reinforced composite, milled zirconium oxide, and additively manufactured cobalt–chromium—were evaluated using compressive-deflection tests. The specimens were subjected to a 45° compressive load extending 5 mm from a metal core. Their mechanical properties were analyzed using one-way ANOVA and Tukey’s post hoc test. Significant differences were observed among the materials. Quartz fiber posts, with the lowest force resistance, buckled at lower loads (143.3 ± 9.9 N), while zirconia posts failed in a brittle manner at higher forces (246.1 ± 97.2 N). Cobalt–chromium posts demonstrated the highest maximal force (323.2 ± 10.5 N, p < 0.001) and, unlike the other materials, bent rather than fractured. The failure patterns of the tested materials underscore the importance of careful material selection when restoring root-treated teeth. Despite displaying distinct fracture characteristics, zirconium oxide, due to its color, rigidity, and hardness, stands out as a promising material for future dental applications. Further research through randomized clinical trials is recommended to refine treatment approaches and optimize clinical outcomes. Full article

FRCs (Fiber-Reinforced Composites) are materials that are being used increasingly more often in dentistry as an alternative to traditional restorations made of ceramics or metals. The aim of this study was to carry out a comparative analysis of the strength parameters of a light-curable dental composite reinforced with one single band and two single bands of artificial fibers. The specimens for the strength tests were prepared in accordance with the guidelines of the PN-EN ISO 4049:2019-07 international standard. The test material covered specimens of composite reinforced with single (one or two) bands of fibers. The following bands of fibers were used: carbon (WGL), aramid (AMD) and hybrid carbon–aramid (WGL-AMD). The presence of one single band of aramid fibers caused a three-fold increase in deflection, with a simultaneous increase in the Young’s modulus of over 140%. The flexural strength of specimens reinforced with one single band of aramid fibers was higher by 280% than that control group specimens (KONT). To summarize the performed tests, the incorporation of carbon, aramid and hybrid carbon–aramid fibers into organic matrix has a significant impact on the values of the mechanical parameters of dental composites. The results indicate that particular attention should be paid to aramid fibers, which have rarely been used in dentistry so far. Full article

The aim of the present in vitro comparative study is to validate a novel composite polymer, named “ONLY”, developed to overcome the mechanical drawbacks of conventional, metal-reinforced poly(methyl methacrylate) (PMMA) interim restoration. Ten interim restorations were designed and fabricated (five in the composite “ONLY” group, and five in the metal-reinforced PMMA group). All the samples were screwed into the prototype models, simulating a complete edentulous mandible rehabilitated with six straight implants. Outcome measures were break point (load, N) and displacement (mm) through a static compression test, and material behavior through a dynamic cyclic test method (fatigue test). A total of 20 samples were tested (10 for static and 10 for dynamic). In each group, five samples (test and control) were used. All the specimens completed the mechanical tests, as planned. There was no statistically significant difference between groups for any test. In the test group, the break point was 1953.19 ± 543.73 N, while it was 2031.10 ± 716.68 N in the control group (p = 0.775). The displacement was 1.89 ± 0.34 mm in the test group and 1.98 ± 0.75 mm in the control group (p = 0.763). Using the dynamic cyclic test method, in the control group the mean load was 2504.60 ± 972.15 N, while in the test group the mean load was 3382.00 ± 578.50 N. The difference between groups was 877.40 ± 579.30 N (p value = 0.121). Within the limitations of this in vitro study, the novel composite polymer can be used to immediately load dental implants. Further clinical research is needed to confirm these preliminary results. Full article

Reconstructive and regenerative bone surgery is based on the use of high-tech biocompatible implants needed to restore the functions of the musculoskeletal system of patients. Ti6Al4V is one of the most widely used titanium alloys for a variety of applications where low density and excellent corrosion resistance are required, including biomechanical applications (implants and prostheses). Calcium silicate or wollastonite (CaSiO₃) and calcium hydroxyapatite (HAp) is a bioceramic material used in biomedicine due to its bioactive properties, which can potentially be used for bone repair. In this regard, the research investigates the possibility of using spark plasma sintering technology to obtain new CaSiO₃-HAp biocomposite ceramics reinforced with a Ti6Al4V titanium alloy matrix obtained by additive manufacturing. The phase and elemental compositions, structure, and morphology of the initial CaSiO₃-HAp powder and its ceramic metal biocomposite were studied by X-ray fluorescence, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Brunauer–Emmett–Teller analysis methods. The spark plasma sintering technology was shown to be efficient for the consolidation of CaSiO₃-HAp powder in volume with a Ti6Al4V reinforcing matrix to obtain a ceramic metal biocomposite of an integral form. Vickers microhardness values were determined for the alloy and bioceramics (~500 and 560 HV, respectively), as well as for their interface area (~640 HV). An assessment of the critical stress intensity factor K_Ic (crack resistance) was performed. The research result is new and represents a prospect for the creation of high-tech implant products for regenerative bone surgery. Full article