Search Results (38)

This study presents a methodology for developing and validating digital models of tooth-inlay systems, aiming to trace the complete workflow from clinical procedures to simulation by involving dental professionals—dentists for manual cavity preparation and dental technicians for restoration modelling—while integrating micro-computed tomography (micro-CT) imaging with finite element analysis (FEA). The proposed workflow includes (1) the acquisition of high-resolution 3D micro-CT scans of a non-restored tooth, (2) image segmentation and reconstruction to create anatomically accurate digital twins and mesh generation, (3) the selection of proper resin and the 3D printing of four typodonts, (4) the manual preparation of cavities on the typodonts, (5) the acquisition of high-resolution 3D micro-CT scans of the typodonts, (6) mesh generation, digital inlay and onlay modelling and material property assignment, and (7) nonlinear FEA simulations under representative masticatory loading. The approach enables the visualisation of stress and deformation patterns, with preliminary results indicating stress concentrations at the tooth-restoration interface integrating different cavity alternatives and restorations on the same tooth. Quantitative outputs include von Mises stress, strain energy density, and displacement distribution. This study demonstrates the feasibility of using image-based, tooth-specific digital twins for biomechanical modelling in dentistry. The developed framework lays the groundwork for future investigations into the optimisation of restoration design and material selection in clinical applications. Full article

Prolonged conflicts in Iraq over the past four decades have profoundly disrupted environmental systems, not only through immediate post-conflict emissions—such as residues from munitions and explosives—but also via long-term infrastructural collapse, population displacement, and unsustainable resource practices. Despite growing concern over air quality in conflict-affected regions, comprehensive assessments integrating long-term data and localized measurements remain scarce. This study addresses this gap by analyzing the environmental consequences of sustained instability in Mosul, focusing on air pollution trends using both remote sensing data (1983–2023) and in situ monitoring of key pollutants—including PM_2.5, PM₁₀, TVOCs, NO₂, SO₂, and formaldehyde—at six urban sites during 2022–2023. The results indicate marked seasonal variations, with winter peaks in combustion-related pollutants (NO₂, SO₂) and elevated particulate concentrations in summer driven by sandstorm activity. Annual average concentrations of all six pollutants increased by 14–51%, frequently exceeding WHO air quality guidelines. These patterns coincide with worsening meteorological conditions, including higher temperatures, reduced rainfall, and more frequent storms, suggesting synergistic effects between climate stress and pollution. The findings highlight severe public health risks and emphasize the urgent need for integrated urban recovery strategies that promote sustainable infrastructure, environmental restoration, and resilience to climate change. Full article

Conservation of ecologically important freshwater mussels is high on the international agenda, but there is only limited knowledge about the status of rare unionid species in arid and semi-arid areas which are particularly vulnerable. One such example concerns Anodonta vescoiana which was recognized as one of the few endemic species of unionid mussels from Iraq and was restricted to the marshes of southern Mesopotamia and its connected river systems. The last confirmed report of A. vescoiana was in 2009 from the Al-Ezz River. We conducted extensive field surveys during the years 2021 and 2022 at approximately 20 freshwater sites, but we failed to observe any live or dead specimens, suggesting a probable extirpation or severe decline. In contrast, we documented the invasive Sinanodonta woodiana at numerous sites across the Tigris–Euphrates basin including the Al-Ezz River. This documentation of S. woodiana indicates successful establishment of the species and colonization of freshwater systems modified by anthropogenic practices, which include alterations of hydrological dynamics and ecological conditions. Here, we compile existing evidence of the global ecological impacts and development of S. woodiana invasion, while also highlighting Iraq as an important example of the displacement of native unionid mussel species by invasive alien unionids. We assessed the factors that contributed to the disappearance of A. vescoiana in Iraq including biological competition (with S. woodiana), salinity stress, habitat fragmentation, and pollution. The time window to act and prevent the further decline of rare unionid species in Iraq, as well as other arid and semi-arid areas which face similar threats, is short. Urgent actions include systematic monitoring to identify remnant populations, implementing biosecurity policies (for fisheries or habitats), and restoration (of habitats) to secure the long-term persistence of remaining unionid diversity. Full article

The Tankou area is a vital production capacity replacement area in the Jianghan oilfield. The recovery of the amount of erosion in Qianjiang Formation and Jinghezhen Formation is significant for studying this area’s tectonic evolution and geothermal history. The target layer, characterised by well-developed plastic materials, intense tectonic deformation, and insufficient well data, fails to meet the applicability criteria of the conventional denudation estimation methods. This study proposes a novel approach based on the structural strain characteristics. The method estimates the stratigraphic denudation by analysing residual formation features and fault characteristics. First, a stress analysis is performed using the fault characteristics, and the change law for the thickness of the target layer is summarised based on the characteristics of the residual strata to recover the amount of erosion in the profile. Second, a grid of the stratigraphic lines in the profiles of the main line and the tie line is used to complete the recovery of the amount of erosion in the plane through interpolation, and the results of the profile recovery are corrected again. Finally, the evolution results of the geological equilibrium method and the stress–strain analysis are compared to analyse the reasonableness of their differences and verify the accuracy of the erosion recovery results. The area of erosion in each layer increases from bottom to top. The amount of denudation in each layer gradually increases from the denudation area near the southern slope to the surrounding area. It converges to 0 at the boundary of the denudation area. The maximum amount of erosion is distributed in the erosion area close to the side of the residual layer with a low dip angle. The specific denudation results are as follows: Qian1 Member + Jinghezhen Formation has a denudation area of 6.3 km² with a maximum denudation thickness of 551 m; Qian2 Member has a denudation area of 2.6 km² with a maximum denudation thickness of 164 m; Qian3 Member has a denudation area of 2.3 km² with a maximum denudation thickness of 215 m; Upper Qian4 Submember has a denudation area of 1.54 km² with a maximum denudation thickness of 191 m; and Lower Qian4 Submember has a denudation area of 1.2 km² with a maximum denudation thickness of 286 m. This method overcomes the conventional denudation restoration approaches’ reliance on well logging and geochemical parameters. Using only seismic interpretation results, it achieves relatively accurate denudation restoration in the study area, thereby providing reliable data for timely analyses of the tectonic evolution, sedimentary facies, and hydrocarbon distribution patterns. In particular, the fault displacement characteristics can be employed to promptly examine how reasonable the results on the amount of denudation between faults are during the denudation restoration process. Full article

Background/Objectives: Among the complications of endodontic treatment, root fractures are the most severe and may require tooth extraction. The objective of this study was to develop virtual models of mandibular molars with different endodontic restorations to assess the stress distribution in tooth structures based on the type of corono-radicular restoration, compared with the model of an intact molar. Methods: Four virtual models of a mandibular molar were created: (1) an intact molar with preserved enamel, dentin, dental pulp and cementum; (2) an endodontically treated molar restored with a composite filling; (3) a molar restored with a fiberglass post and monolithic zirconia crown; (4) a molar restored with a metal cast post and monolithic zirconia crown. External force loads from 0 to 800 N were simulated using Finite Element Method (FEM). Results: The highest displacement, strain and stress values were observed in the molar restored with a composite filling, whereas the lowest values were recorded in the molar restored with a fiberglass post and zirconia crown. Critical stresses were primarily concentrated on the pulp chamber floor. Conclusions: The pulp chamber floor was identified as the most vulnerable area for fracture. This underscores the importance of preserving tooth structure to enhance the strength and durability of molars throughout and beyond endodontic treatment. Full article

Developmental dysplasia of the hip, particularly Crowe type IV, presents significant challenges in orthopedic surgery due to severe anatomical deformities and biomechanical instability. This study focuses on evaluating the biomechanical performance of a prosthesis–femur–derotation plate system designed to address these challenges. Using FEA, a comprehensive assessment of stress distribution, displacement, and safety factors was conducted under physiological loading conditions. The derotation plate was specifically engineered to stabilize the femur and restore the anatomical and biomechanical axis of the limb. Results demonstrated that the derotation plate effectively eliminated rotational and axial displacement, with a peak displacement of 0.08 mm, and maintained sufficient strength reserves, with a minimum safety factor of 3.63. The maximum von Mises stress in the plate was 76 MPa, significantly below the yield strength of the titanium alloy, ensuring long-term durability and reliability. The system as a whole exhibited favorable biomechanical properties, confirming its ability to manage high stress loads without the risk of material failure or instability. These findings underscore the potential of this novel system to improve surgical outcomes in complex cases of hip dysplasia. Future clinical trials will further validate its practical utility, providing valuable insights for advancing orthopedic implant design and patient care. Full article

Hydroxyapatite (HAP) inserts minimize restoration contraction by constituting a major part of the restoration; however, their effect on the relaxation of tooth tissues has not been previously tested. Finite element analysis was employed to estimate stress and displacement when HAP inserts with a thickness of 1.7 mm or 4.7 mm and a diameter of 4.7 mm were used to substitute for dentin. The volumetric contraction of the composite during polymerization, simulated through steady-state heat transfer analysis, yielded a contraction rate of 3.7%. Descriptive statistics revealed that the incorporation of HAP inserts reduced the displacement of dentin, enamel, and restoration caused by contraction by 44.4% to 66.7%, while maximal stress was reduced by 8.1% to 52%. Subsequent loading on the occlusal tooth surface showed that displacement values decreased by 12.1% to 33.3%, while maximum von Mises stress in enamel decreased by 32.8% to 40.6% with the use of HAP inserts. Although the maximum stress values in dentin were not significantly decreased (3% to 8.8%), the stress located at the bottom of the cavity was notably reduced, particularly in deep cavities at root canal entrances. The use of HAP inserts in restorative dentistry provides benefits for the preservation of prepared teeth, especially in preventing irreparable vertical root fractures of endodontically treated teeth. Full article

The eastern segment of the Sunan-Qilian Fault (ES-SQF) is located within the seismic gap between the 1927 M8.0 Gulang earthquake and the 1932 M7.6 Changma earthquake in China. It also aligns with the extension direction of the largest surface rupture zone associated with the 2022 Mw6.7 Menyuan earthquake. Understanding the activity parameters of this fault is essential for interpreting strain distribution patterns in the central–western segment of the Qilian–Haiyuan fault zone, located along the northeastern margin of the Tibetan Plateau, and for evaluating the seismic hazards in the region. High-resolution Google Earth satellite imagery and UAV (Unmanned Aerial Vehicle)-based photogrammetry provide favorable conditions for detailed mapping and the study of typical landforms along the ES-SQF. Combined with field geological surveys, the ES-SQF is identified as a continuous, singular-fault structure extending approximately 68 km in length. The fault trends in the WNW direction and along its trace, distinctive features, such as ridges, gullies, and terraces, show clear evidence of synchronous left lateral displacement. This study investigates the Qingsha River and the Dongzhong River. High-resolution digital elevation models (DEMs) derived from UAV imagery were used to conduct a detailed mapping of faulted landforms. An analysis of stripping trench profiles and radiocarbon dating of collected samples indicates that the most recent surface-rupturing seismic event in the area occurred between 3500 and 2328 y BP, pointing to the existence of an active fault from the Holocene epoch. Using the LaDiCaoz program to restore and measure displaced terraces at the study site, combined with geomorphological sample collection and testing, we estimated the fault’s slip rate since the Holocene to be approximately 2.0 ± 0.3 mm/y. Therefore, the ES-SQF plays a critical role in strain distribution across the central–western segment of the Qilian–Haiyuan fault zone. Together with the Tuolaishan fault, it accommodates and dissipates the left lateral shear deformation in this region. Based on the slip rate and the elapsed time since the last event, it is estimated that a seismic moment equivalent to Mw 7.5 has been accumulated on the ES-SQF. Additionally, with the significant Coulomb stress loading on the ES-SQF caused by the 2016 Mw 5.9 and 2022 Mw 6.7 Menyuan earthquakes, there is a potential for large earthquakes to occur in the future. Our results also indicate that high-resolution remote sensing imagery can facilitate detailed studies of active tectonics. Full article

The preservation of cultural heritage and the seismic resilience of historic buildings are crucial for maintaining social identity, particularly in earthquake-prone regions. This study focuses on the modeling of Sırçalı Kumbet, a Seljuk monument built in the 14th century in Kayseri province, located in the Central Anatolia region of Turkey, using survey drawings and analysis using the finite element method (FEM) to evaluate its seismic performance. The analysis indicates that linear elastic calculation methods can serve as an initial approach for evaluating such geometrically complex structures. The findings demonstrate that Sırçalı Kumbet exhibits substantial structural rigidity, reducing deformation and enhancing resistance to material fatigue during seismic events. Displacement and stress analyses under G+EQx and G+EQy loading conditions reveal that tensile and compressive stresses remain within acceptable limits, with localized exceedances occurring at specific points, such as cavity corners and wall bases. While these localized stresses are manageable, they highlight areas that require continuous monitoring and potential reinforcement to ensure long-term stability. Additionally, the study suggests that the integration of regular maintenance and targeted reinforcement measures can further improve the monument’s durability and minimize potential damage. This research underscores the essential role of the FEM in bridging the gap between cultural heritage conservation and seismic resilience. It provides a methodological framework for integrating architectural, restoration, and engineering expertise into comprehensive conservation strategies. Future studies should expand this approach to include various building types and material properties to enhance the development of preservation strategies. Full article

The root systems of vegetation significantly contribute to enhancing slope stability. The shear strength of soil–root systems is a crucial parameter for assessing slope stability. This study focuses on six types of vegetation in the Yellow River Basin of China (woodland: Populus przewalskii and Broussonetia papyrifera; shrubland: Periploca sepium and Ziziphus jujuba; grassland: Artemisia hedinii and Setaria viridis), employing in situ shear tests and the Wu–Waldron model (Wu model) to investigate the shear strength of soil–root systems. The results show that the shear stress–displacement curves for P. przewalskii, B. papyrifera, and Z. jujuba are higher and steeper, with clear inflection points. The tensile strength of the roots from the six vegetation types decreases as the root diameter increases. According to the Wu model, the additional root cohesion is ranked as follows: A. hedinii > B. papyrifera > P. przewalskii > Z. jujuba > P. sepium > S. viridis. Based on the in situ shear tests, the shear strength increments are ranked as follows: Z. jujuba > B. papyrifera > P. przewalskii > A. hedinii > P. sepium > S. viridis. Overall, the additional root cohesion obtained by the Wu model in each soil layer is greater than the shear strength increment measured from the in situ shear tests. In the 0–30 cm soil layers, the soil–root systems of Z. jujuba, B. papyrifera, P. przewalskii, and A. hedinii exhibit a better shear strength, whereas P. sepium and S. viridis perform poorly. A principal component analysis reveals that the shear strength of the soil–root systems of different vegetation types is primarily influenced by the soil moisture content and root mass density. Z. jujuba, B. papyrifera, P. przewalskii, and A. hedinii are recommended for ecological restoration projects in the Yellow River Basin of China. Full article

Background: The literature highlights the profound psychological impact of war on children, families, and communities, emphasizing the prevalence of Post-Traumatic Stress Disorder (PTSD), anxiety, and other symptoms among affected individuals. Interventions, such as Child-Parent Psychotherapy (CPP) and music therapy, show promise in mitigating trauma effects, underscoring the need for holistic approaches that address familial and community dynamics alongside individual well-being. Methods: Aiming to explore the influences of dyadic music therapy sessions on parents’ capacity to support their children, this study involved four families displaced from their home-kibbutz as result of a terrorist attack. All dyads participated in music therapy sessions with a focus on parent–child interactions and trauma processing (CPP informed). Embedded in a qualitative, phenomenological approach, the research utilized interpretative phenomenological analysis (IPA) and micro-analytic methods to explore meaningful moments in the music therapy sessions. Results: Findings identified four central categories: (1) Discovering the child’s grounding song: identifying resources; (2) Musical improvisation sets the grounds for parent–child mutual recognition of the child’s traumatic experience; (3) Musical performance empowers child and parent; (4) A sense of agency is gained through controlling the musical environment. Conclusions: The significance of restoring the children’s freedom of play, the parents’ sense of competency, and of enhancing families’ capacity to connect to their traumatic experiences through the musical environment is discussed. Full article

The Karnak Temples complex, a monumental site dating back to approximately 1970 BC, faces significant preservation challenges due to a confluence of mechanical, environmental, and anthropogenic factors impacting its stone blocks. This study provides a comprehensive evaluation of the deterioration affecting the northeast corner of the complex, revealing that the primary forms of damage include split cracking and fracturing. Seismic activities have induced out-of-plane displacements, fractures, and chipping, while flooding has worsened structural instability through uplift and prolonged water exposure. Soil liquefaction and fluctuating groundwater levels have exacerbated the misalignment and embedding of stone blocks. Thermal stress and wind erosion have caused microstructural decay and surface degradation and contaminated water sources have led to salt weathering and chemical alterations. Multi-temporal satellite imagery has revealed the influence of vegetation, particularly invasive plant species, on physical and biochemical damage to the stone. This study utilized in situ assessments to document damage patterns and employed satellite imagery to assess environmental impacts, providing a multi-proxy approach to understanding the current state of the stone blocks. This analysis highlights the urgent need for a multi-faceted conservation strategy. Recommendations include constructing elevated platforms from durable materials to reduce soil and water contact, implementing non-invasive cleaning and consolidation techniques, and developing effective water management and contamination prevention measures. Restoration should focus on repairing severely affected blocks with historically accurate materials and establishing an open museum setting will enhance public engagement. Long-term preservation will benefit from regular monitoring using 3D scanning and a preventive conservation schedule. Future research should explore non-destructive testing and interdisciplinary collaboration to refine conservation strategies and ensure the sustained protection of this invaluable historical heritage. Full article

The design of the access cavity is an important factor in endodontic treatment for the further evolution of the tooth. The objective of this study was to highlight the most favorable access cavity design (TrussAC, UltraAC, TradAC, CariesAC, ConsAC, RestoAC) based on the stress distribution on virtual models of mandibular molars. To achieve the objectives of the study, four series of virtual models of six molars were made. The first two series of external virtual models were obtained based on the three-dimensional scanning of the molars before the access cavity preparation and after their restoration, to obtain the density of the restorative materials. Internal morphology was added to the next two series of virtual models and after that, materials were added, specific for root canal obturation and coronal restoration. The simulations were performed for two coronary restoration materials, bulk fill composite and amalgam. The results showed, based on the stress maps, that the highest values were recorded for CariesAC and the lowest values for UltraAC. Comparing the two restorative materials, the lowest level of stress, strains, and displacements was highlighted in the case of UltraAC, TradAC, and ConsAC cavities for amalgam. The results obtained in this study should guide doctors towards a conservative attitude with the preservation of as much hard tissue as possible and the differentiated use of restorative materials according to the amount of tissue lost when preparing the access cavity. Full article

On the human face, the lips are one of the most important anatomical elements, both morphologically and functionally. Morphologically, they have a significant impact on aesthetics, and abnormal lip morphology causes sociopsychological problems. Functionally, they play a crucial role in breathing, articulation, feeding, and swallowing. An apparatus that can accurately and easily measure the elastic modulus of perioral tissues in clinical tests was developed, and its measurement sensitivity was evaluated. The apparatus is basically a uniaxial compression apparatus consisting of a force sensor and a displacement sensor. The displacement sensor works by enhancing the restoring force due to the deformation of soft materials. Using the apparatus, the force and the displacement were measured for polyurethane elastomers with various levels of softness, which are a model material of human tissues. The stress measured by the developed apparatus increased in proportion to Young’s modulus, and was measured by the compression apparatus at the whole region of Young’s modulus, indicating that the relation can be used for calibration. Clinical tests using the developed apparatus revealed that Young’s moduli for upper lip, left cheek, and right cheek were evaluated to be 45, 4.0, and 9.9 kPa, respectively. In this paper, the advantages of this apparatus and the interpretation of the data obtained are discussed from the perspective of orthodontics. Full article

Inflammation of the bile ducts and surrounding tissues can impede bile flow from the liver into the intestines. If this occurs, a plastic or self-expanding metal (SEM) stent is placed to restore bile drainage. United States (US) Food and Drug Administration (FDA)-approved plastic biliary stents are less expensive than SEMs but have limited patency and can occlude bile flow if placed spanning a duct juncture. Recently, we investigated the effects of variations to post-processing and autoclaving on a commercially available stereolithography (SLA) resin in an effort to produce a suitable material for use in a biliary stent, an FDA Class II medical device. We tested six variations from the manufacturer’s recommended post-processing and found that tripling the isopropanol (IPA) wash time to 60 min and reducing the time and temperature of the UV cure to 10 min at 40 °C, followed by a 30 min gravity autoclave cycle, yielded a polymer that was flexible and non-cytotoxic. In turn, we designed and fabricated customizable, SLA 3D-printed polymeric biliary stents that permit bile flow at a duct juncture and can be deployed via catheter. Next, we generated an in silico stent 3-point bend test to predict displacements and peak stresses in the stent designs. We confirmed our simulation accuracy with experimental data from 3-point bend tests on SLA 3D-printed stents. Unfortunately, our 3-point bend test simulation indicates that, when bent to the degree needed for placement via catheter (~30°), the peak stress the stents are predicted to experience would exceed the yield stress of the polymer. Thus, the risk of permanent deformation or damage during placement via catheter to a stent printed and post-processed as we have described would be significant. Moving forward, we will test alternative resins and post-processing parameters that have increased elasticity but would still be compatible with use in a Class II medical device. Full article