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Keywords = temporary filling materials

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29 pages, 15135 KiB  
Article
Fatigue Analysis of 3D-Printed Materials for Temporary Reconstructions on Dental Implants—A Pilot Study
by Adam Nowicki, Karina Krawiec, Karolina Osypko, Adam Kurzawa, Mateusz Stachowicz, Piotr Kotowski and Dariusz Pyka
Appl. Sci. 2025, 15(6), 3212; https://doi.org/10.3390/app15063212 - 15 Mar 2025
Viewed by 1245
Abstract
The rapid development of 3D printing technology has enabled its application in many fields, including dentistry. One of the key applications is temporary prosthetic restorations on dental implants, used during the osteointegration process. These restorations provide functionality and aesthetics, but their durability under [...] Read more.
The rapid development of 3D printing technology has enabled its application in many fields, including dentistry. One of the key applications is temporary prosthetic restorations on dental implants, used during the osteointegration process. These restorations provide functionality and aesthetics, but their durability under oral conditions exposed to dynamic loads remains a challenge. This pilot study evaluated the thermal expansion and fatigue resistance of three commercially available photopolymer materials used in 3D printing: NextDent Denture 3D, NextDent C&B MFH Bleach, and Graphy TC-80DP. Thermal expansion and dimensional stability analyses were performed on samples subjected to cyclic heating and cooling. Fatigue tests were designed to evaluate the behaviour of the materials under repetitive mechanical loads mimicking chewing. Microscopic analyses (SEM) made it possible to identify the internal structure of the materials and their damage mechanisms. The results showed that the tested materials have a low coefficient of thermal expansion and high dimensional stability after cyclic heating and cooling. However, significant differences were observed in their mechanical properties and fatigue resistance. The best results were obtained for the Graphy TC-80DP material, while NextDent Denture 3D showed the least resistance to cyclic loading. NextDent Denture 3D exhibited the highest thermal expansion coefficient (123.6 × 10−6/K), while Graphy TC-80DP showed the lowest (83.9 × 10−6/K), ensuring better dimensional stability. Fatigue tests revealed that Graphy TC-80DP withstood up to 675,221 cycles at 51 MPa, while NextDent Denture 3D failed after 420 cycles. SEM analysis confirmed that Graphy TC-80DP maintained structural integrity longer, while NextDent Denture 3D exhibited early crack propagation. This study fills a gap in the knowledge of the behaviour of dental materials produced with 3D printing technology under real-world conditions and provides a basis for further, more advanced research to improve their properties and patient comfort. Full article
(This article belongs to the Special Issue Fatigue Strength of Machines and Systems)
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12 pages, 274 KiB  
Reply
On the Inconsistency of the “Suid Gap” Hypothesis and Its Inappropriate Biochronological Use in Dating the Localities of Orce (Venta Micena, Barranco León D, and Fuente Nueva 3). Reply to Martínez-Navarro et al. Comment on “Iannucci, A. The Occurrence of Suids in the Post-Olduvai to Pre-Jaramillo Pleistocene of Europe and Implications for Late Villafranchian Biochronology and Faunal Dynamics. Quaternary 2024, 7, 11”
by Alessio Iannucci
Quaternary 2025, 8(1), 8; https://doi.org/10.3390/quat8010008 - 6 Feb 2025
Cited by 1 | Viewed by 1394
Abstract
According to the “suid gap” hypothesis, suids (Suidae, Mammalia) would have been absent from Europe between 1.8 and 1.2 Ma. This hypothesis has been influential owing to its putative implications for biochronology and paleoecology—Sus scrofa (the modern wild boar) would appear 1.2 [...] Read more.
According to the “suid gap” hypothesis, suids (Suidae, Mammalia) would have been absent from Europe between 1.8 and 1.2 Ma. This hypothesis has been influential owing to its putative implications for biochronology and paleoecology—Sus scrofa (the modern wild boar) would appear 1.2 Ma in a period of climatic and environmental changes, coinciding with the beginning of the Epivillafranchian and the Early–Middle Pleistocene Transition, and hominins—the arrival of Homo in western Europe would precede the “return” of pigs. However, the “suid gap” hypothesis is based on the wrong premises that suids are abundantly represented in the European fossil record before and after the “suid gap”, that this purported abundance is linked to the suid reproductive potential, and that the paleontological sites dated within the 1.8–1.2 Ma interval yielded enough remains to exclude the notion that the absence of suid is merely accidental. In a recent paper, it is shown that all these assumptions are erroneous and suid material is described from Peyrolles (France), which is dated at 1.47 ± 0.01 Ma, hence perfectly “filling the suid gap”. Some proposers of the “suid gap” hypothesis have now provided comments to this recent paper, casting doubt on the age of Peyrolles and reiterating the arbitrary statement that suids were commonly recorded and abundantly represented in the Pleistocene of Europe. There is no valid reason to question the homogeneity of the faunal assemblage of Peyrolles, which is indeed a key locality for the mammal biochronology of Europe, being the reference for MNQ 19. Suids of comparable chronology have also been found in Krimni (Greece). Moreover, the “suid gap” proposers are basically advocating the use of an interval biozone based on the temporary absence of Sus strozzii—a species not common in the Pleistocene of Europe—providing no ecological explanation for this gap, apart from speculating it would be due to competition with Homo. The defense of the “suid gap” seems motivated by its use from the “suid gap” proposers as a biochronological argument to contend that the localities of Orce in Spain (Barranco León D, Fuente Nueva 3, and Venta Micena) are older than 1.2 Ma, when they postulated suids would “reappear” in the fossil record. However, since the “suid gap” hypothesis was primarily proposed based on the absence of suids from the Orce sites (and, secondarily, from other sites biochronologically correlated with the localities of Orce, like Pirro Nord in Italy), this represents an evident example of circular reasoning. Full article
14 pages, 3232 KiB  
Article
Experimental Investigation on Unloading-Induced Sliding Behavior of Dry Sands Subjected to Constant Shear Force
by Wengang Dang, Kang Tao, Jinyang Fu and Bangbiao Wu
Appl. Sci. 2025, 15(1), 401; https://doi.org/10.3390/app15010401 - 3 Jan 2025
Cited by 1 | Viewed by 890
Abstract
Infilled joints or faults are often subjected to long-term stable shear forces, and nature surface processes of normal unloading can change the frictional balance. Therefore, it is essential to study the sliding behavior of such granular materials under such unloading conditions, since they [...] Read more.
Infilled joints or faults are often subjected to long-term stable shear forces, and nature surface processes of normal unloading can change the frictional balance. Therefore, it is essential to study the sliding behavior of such granular materials under such unloading conditions, since they are usually the filling matter. We conducted two groups of normal unloading direct shear tests considering two variables: unloading rate and the magnitude of constant shear force. Dry sands may slide discontinuously during normal unloading, and the slip velocity does not increase uniformly with unloading time. Due to horizontal particle interlacing and normal relaxation, there will be sliding velocity fluctuations and even temporary intermissions. At the stage of sliding acceleration, the normal force decreases with a higher unloading rate and increases with a larger shear force at the same sliding velocity. The normal forces obtained from the tests are less than those calculated by Coulomb’s theory in the conventional constant-rate shear test. Under the same unloading rate, the range of apparent friction coefficient variation is narrower under larger shear forces. This study has revealed the movement patterns of natural granular layers and is of enlightening significance in the prevention of corresponding geohazards. Full article
(This article belongs to the Topic Geotechnics for Hazard Mitigation)
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17 pages, 15342 KiB  
Article
Experimental Study on the Mechanical Properties of Reactive Powder Concrete Ultra-Thin Precast Slab for Bridge I-Beam Joints
by Jinling Lan, Jinxin Dai, Buyu Jia, Quansheng Yan and Zheng Yang
Buildings 2024, 14(12), 3977; https://doi.org/10.3390/buildings14123977 - 14 Dec 2024
Cited by 2 | Viewed by 897
Abstract
In the domain of bridge I-beam joint construction, conventional approaches such as cast-in-place concrete with suspended formwork and ordinary reinforced concrete precast slabs entail numerous limitations. The former features complex procedures, elevated costs, and significant safety risks, while the latter is hindered by [...] Read more.
In the domain of bridge I-beam joint construction, conventional approaches such as cast-in-place concrete with suspended formwork and ordinary reinforced concrete precast slabs entail numerous limitations. The former features complex procedures, elevated costs, and significant safety risks, while the latter is hindered by the heavy weight of precast slabs, which causes difficulties in transportation and hoisting, inconvenient installation, and high costs. Reactive powder concrete ultra-thin precast slab (RPCUPS) is regarded as a potential solution due to its superior properties. Nevertheless, at present, there is an acute paucity of experience and research regarding the application of RPCUPS in bridge I-beam joints, particularly on a large scale. In a certain actual engineering project, a scheme was proposed to employ RPCUPS with a mere thickness of 20 mm in the bridge I-beam joints. In this scheme, the quantity of slabs is substantial, amounting to over 600,000. This constitutes the research gap and impetus of this study, with the aim of filling the existing knowledge void and providing technical support for engineering endeavors. This research carried out an extensive experimental test to systematically investigate the mechanical properties and safety of RPCUPS. Firstly, the material performance experiments were conducted to determine the manufacturing process of RPCUPS that meets the performance requirements. Subsequently, loading experiments on specimens under multiple working conditions were performed to disclose the cracking load and ultimate load of the two main types of RPCUPS and to analyze the influences of fiber type, mixing type, steel mesh, and slab thickness on the mechanical properties of RPCUPS (keeps the same volume rate of steel in a slab). Key findings encompass the outstanding mechanical properties and high safety factors of RPCUPS under diverse working conditions. Finally, in light of the actual construction environment, safety verification of temporary loading during actual construction was executed to furnish solid technical support for the practical engineering application of RPCUPS. The experimental results indicate that RPCUPS has been successfully applied on a large scale in actual engineering projects, not only without augmenting the cost but also significantly reducing the construction period by approximately five months, conspicuously enhancing the construction efficiency. These discoveries not only validate the feasibility of RPCUPS in bridge I-beam joint construction but also offer valuable references and guidance for similar future projects. Full article
(This article belongs to the Section Building Structures)
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15 pages, 4466 KiB  
Article
Degradable Gel for Temporary Plugging in High Temperature Reservoir and Its Properties
by Fan Yang, Jinhua Liu, Renjing Ji, Xiaorong Yu, Huan Yang and Gaoshen Su
Gels 2024, 10(7), 445; https://doi.org/10.3390/gels10070445 - 5 Jul 2024
Cited by 4 | Viewed by 1810
Abstract
Although various degradable gel materials have been developed for temporary plugging in oil fields, they often degrade too quickly in high-temperature environments. To address this issue, an unstable crosslinker was synthesized to prepare a high-temperature degradable gel. This gel does not degrade excessively [...] Read more.
Although various degradable gel materials have been developed for temporary plugging in oil fields, they often degrade too quickly in high-temperature environments. To address this issue, an unstable crosslinker was synthesized to prepare a high-temperature degradable gel. This gel does not degrade excessively fast at high temperatures. Temperature and crosslinker concentration are the primary factors influencing gel degradation time, followed by monomer and initiator concentrations. Increased temperature and decreased crosslinker concentration both reduce degradation time, which can be adjusted within the range of 90–130 °C by varying the crosslinker concentration. The molecular structure and thermal stability of the degradable gel were analyzed using FTIR, 13C NMR, and TG. Furthermore, the viscoelastic properties, compressive performance, plugging performance, and core damage performance of the gel were evaluated. Within the test range of 0.1–1000 Pa, the storage modulus is higher than the loss modulus. The gel prepared at 130 °C exhibited a compressive stress of 0.25 MPa at 50% strain. The plugging pressure of the gel in sand-filled tubes with varying permeabilities (538.2–2794.1 mD) exceeded 15 MPa while maintaining a core damage rate below 5%. SEM analysis indicated that the degradation mechanism of the gel may involve the collapse of its three-dimensional network structure due to the hydrolysis of amide groups in the crosslinker. The viscosity of the degradation liquid was below 11 mPa·s, enabling it to be brought back to the surface with the formation fluid without the need for further breaking operations. Full article
(This article belongs to the Special Issue Gels in the Oil Field)
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22 pages, 649 KiB  
Review
Effect of Immediate Dentin Sealing on the Bonding Performance of Indirect Restorations: A Systematic Review
by Fusun Ozer, Zeynep Batu Eken, Jessica Hao, Nuray Tuloglu and Markus B. Blatz
Biomimetics 2024, 9(3), 182; https://doi.org/10.3390/biomimetics9030182 - 17 Mar 2024
Cited by 5 | Viewed by 8030
Abstract
The popular immediate dentin sealing (IDS) technique is used to improve the bond strength of indirect restorations. This systematic review assessed whether bond strength is affected by the type of aging conditions, bonding agents, flowable resin composites, impression materials, temporary materials, and/or resin [...] Read more.
The popular immediate dentin sealing (IDS) technique is used to improve the bond strength of indirect restorations. This systematic review assessed whether bond strength is affected by the type of aging conditions, bonding agents, flowable resin composites, impression materials, temporary materials, and/or resin cement used within the IDS procedure. A comprehensive database search of PubMed, Embase, Scopus, Ovid Medline, Web of Sciences, Cochrane Library, Dentistry & Oral Sciences Source, and ProQuest was carried out up to 30 January 2024 without publication year or language limitations. Only in vitro full-texts regarding the effect of IDS on bond strength were included, and the quality of their methods was assessed via a Risk of Bias (RoB) test. In total, 1023 pertinent studies were initially found, and 60 articles were selected for review after screening for the title, abstract, and full texts. IDS application improves the bond strength of indirect restorations to dentin and reduces the negative effects of temporary materials on the bond durability of final indirect restorations. Filled dentin bonding agents or combinations with flowable resin composite are preferred to protect the IDS layer from conditioning procedures. Full article
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11 pages, 747 KiB  
Article
Temporary Root Canal Obturation with a Calcium Hydroxide-Based Dressing: A Randomized Controlled Clinical Trial
by Johannes-Simon Wenzler, Wolfgang Falk, Roland Frankenberger and Andreas Braun
Antibiotics 2023, 12(12), 1663; https://doi.org/10.3390/antibiotics12121663 - 26 Nov 2023
Cited by 2 | Viewed by 5201
Abstract
Successful bacterial inactivation or elimination is essential for successful outcomes in endodontics. This study investigated the efficacy of a calcium hydroxide paste (Ca(OH)2) as a temporary medical dressing for 1 week after chemomechanical root canal treatment (CMRCT). Microbiological samples from 26 [...] Read more.
Successful bacterial inactivation or elimination is essential for successful outcomes in endodontics. This study investigated the efficacy of a calcium hydroxide paste (Ca(OH)2) as a temporary medical dressing for 1 week after chemomechanical root canal treatment (CMRCT). Microbiological samples from 26 patients were collected after endodontic emergency treatment as follows: (1) removal of the provisional filling material; (2) CMRCT; (3) irrigation with sodium hypochlorite I (3%); (4) medicinal insertion of Ca(OH)2; and (5) irrigation with sodium hypochlorite II (3%). A microbiological examination was carried out after the specimens had been taken from the root canals via saline and sterile paper points. CMRCT resulted in a significant reduction in total bacterial load (TBL) in the root canal (p < 0.05). Additional irrigation (3) resulted in a further significant reduction in TBL (p < 0.05). In contrast, Ca(OH)2 medication did not prevent the bacterial load from returning to the previous level immediately after CMRCT, but did not increase above that level either (p < 0.05). However, the increase in TBL was significant (p < 0.05) in comparison with the disinfection groups (I/II). Administration of Ca(OH)2 for 1 week shows that in combination with an additional disinfection procedure, an increase in TBL must be expected, but not above the level of conditions after CMRCT. Full article
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32 pages, 13479 KiB  
Article
Hominid Alluvial Corridor (HAC) of the Guadalquivir and Guadaíra River Valleys (Southern Spain): Geoarchaeological Functionality of the Middle Paleolithic Assemblages during the Upper Pleistocene
by Fernando Díaz del Olmo, José A. Caro Gómez, César Borja Barrera, José M. Recio Espejo, Rafael Cámara Artigas and Aránzazu Martínez Aguirre
Geosciences 2023, 13(7), 206; https://doi.org/10.3390/geosciences13070206 - 8 Jul 2023
Cited by 1 | Viewed by 1987
Abstract
This research addresses the geomorphological connectivity existing amid the piedmont’s karstic fillings (Sierra de Esparteros) and the Guadaíra and Guadalquivir Rivers’ alluvial terraces (SW of Spain), spotted with vestiges of human activities (Middle Palaeolithic). This study includes the analysis of 20 geoarchaeological sites [...] Read more.
This research addresses the geomorphological connectivity existing amid the piedmont’s karstic fillings (Sierra de Esparteros) and the Guadaíra and Guadalquivir Rivers’ alluvial terraces (SW of Spain), spotted with vestiges of human activities (Middle Palaeolithic). This study includes the analysis of 20 geoarchaeological sites and 28 lithic assemblages, with a total of 13,233 lithic pieces. Techno-typological and use–wear (SEM) analyses were conducted on these artifacts. Depending on the raw materials and the provenance of these lithic industries, two groups of assemblages were identified: one made of quartzite from the north, and another made of flint from the south. Two main geochronological periods were established (OSL and U/Th): (1) a short duration (MIS6/MIS5) and (2) a long duration (MIS5/MIS3). Techno-typological analysis showed three sorts of activities: (a) the provision and distribution of raw materials, (b) knapping, and (c) other activities that imply the use of a lithic workshop (LW), along with the settlement characteristics of habitual or recurrent (HS), temporary (TS), and indeterminate (IN). This geoarchaeological connectivity is called the “hominid alluvial corridor” (HAC). The underlined features are the geomorphological units, the continuum alluvial series, the raw material of the lithic industries as an indicator of provenance and transportation throughout the alluvial system, and the use–wear analysis of the tool-kit to interpret the functionality of the pieces. Full article
(This article belongs to the Special Issue Pleistocene Hunter-Gatherers Geoarchaeology)
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13 pages, 3135 KiB  
Article
Conditional Mitigation of Dental-Composite Material-Induced Cytotoxicity by Increasing the Cure Time
by Takanori Matsuura, Keiji Komatsu, Kimberly Choi, Toshikatsu Suzumura, James Cheng, Ting-Ling Chang, Denny Chao and Takahiro Ogawa
J. Funct. Biomater. 2023, 14(3), 119; https://doi.org/10.3390/jfb14030119 - 22 Feb 2023
Cited by 8 | Viewed by 2295
Abstract
Light-cured composite resins are widely used in dental restorations to fill cavities and fabricate temporary crowns. After curing, the residual monomer is a known to be cytotoxic, but increasing the curing time should improve biocompatibility. However, a biologically optimized cure time has not [...] Read more.
Light-cured composite resins are widely used in dental restorations to fill cavities and fabricate temporary crowns. After curing, the residual monomer is a known to be cytotoxic, but increasing the curing time should improve biocompatibility. However, a biologically optimized cure time has not been determined through systematic experimentation. The objective of this study was to examine the behavior and function of human gingival fibroblasts cultured with flowable and bulk-fill composites cured for different periods of time, while considering the physical location of the cells with regard to the materials. Biological effects were separately evaluated for cells in direct contact with, and in close proximity to, the two composite materials. Curing time varied from the recommended 20 s to 40, 60, and 80 s. Pre-cured, milled-acrylic resin was used as a control. No cell survived and attached to or around the flowable composite, regardless of curing time. Some cells survived and attached close to (but not on) the bulk-fill composite, with survival increasing with a longer curing time, albeit to <20% of the numbers growing on milled acrylic even after 80 s of curing. A few cells (<5% of milled acrylic) survived and attached around the flowable composite after removal of the surface layer, but attachment was not cure-time dependent. Removing the surface layer increased cell survival and attachment around the bulk-fill composite after a 20-s cure, but survival was reduced after an 80-s cure. Dental-composite materials are lethal to contacting fibroblasts, regardless of curing time. However, longer curing times mitigated material cytotoxicity exclusively for bulk-fill composites when the cells were not in direct contact. Removing the surface layer slightly improved biocompatibility for cells in proximity to the materials, but not in proportion to cure time. In conclusion, mitigating the cytotoxicity of composite materials by increasing cure time is conditional on the physical location of cells, the type of material, and the finish of the surface layer. This study provides valuable information for clinical decision making and novel insights into the polymerization behavior of composite materials. Full article
(This article belongs to the Special Issue Feature Papers in Dental Biomaterials)
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9 pages, 906 KiB  
Article
Prevention of Bacterial Infiltration in Class 1 Temporary Restorations Using Zinc Oxide/Calcium Sulphate Filling Materials: An In Vitro Study
by Alessio Buonavoglia, Adriana Trotta, Francesco Pellegrini, Alfredo Iandolo and Marco Cordisco
Appl. Sci. 2023, 13(3), 1748; https://doi.org/10.3390/app13031748 - 30 Jan 2023
Viewed by 2251
Abstract
This study evaluated sealing properties of zinc oxide/calcium sulphate filling material (Plastor©) to prevent bacterial infiltration in simulated Class 1 cavities with and without the presence of a spacer apically the restoration. Twenty-eight experimental Eppendorf tubes containing Tryptic Soy Agar were prepared and [...] Read more.
This study evaluated sealing properties of zinc oxide/calcium sulphate filling material (Plastor©) to prevent bacterial infiltration in simulated Class 1 cavities with and without the presence of a spacer apically the restoration. Twenty-eight experimental Eppendorf tubes containing Tryptic Soy Agar were prepared and divided into seven groups: group A (Plastor©), group B (Plastor© + cotton pellet), group C (Plastor© + cotton pellet soaked of m-cresyl acetate), group D (Plastor© + cotton pellet soaked of eugenol), group E (Plastor© + PTFE pellet), group F (positive control), and group G (negative control). All prepared vials were individually immersed in tubes containing 5 mL of a suspension of Streptococcus mutans (105 CFU/mL) previously prepared and then incubated at 37 °C for 5 and 10 days. Subsequently, agar was collected and tested for S.mutans using real-time PCR. Aliquots of each agar samples were separately seeded on TSA for S. mutans isolation. The real-time PCR tests were negative for S. mutans on all the vials at both T5 and T10, except for positive control resulted positive at both T5 and T10. The isolation tests showed bacterial growth of S. mutans only with the agar samples collected from the vials of positive control, confirming real-time PCR tests. This in vitro study evidenced complete sealing ability of zinc oxide/calcium sulphate in temporary restorations of Class 1 cavities without mechanical loading at 10 days and complete immersion in a bacterial suspension. Moreover, sealing ability is not influenced by presence of spacers. Full article
(This article belongs to the Special Issue Innovative Techniques in Endodontics)
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15 pages, 4334 KiB  
Article
Structural Behaviour of Axially Loaded Concrete-Filled Steel Tube Columns during the Top-Down Construction Method
by Marija M. Lazovic Radovanovic, Jelena Z. Nikolic, Janko R. Radovanovic and Svetlana M. Kostic
Appl. Sci. 2022, 12(8), 3771; https://doi.org/10.3390/app12083771 - 8 Apr 2022
Cited by 7 | Viewed by 3190
Abstract
The paper discusses the structural behaviour of concrete-filled steel tube columns (CFT) when applied to the top-down construction method as temporary internal supports for ceilings. Their ultimate capacity to take into account the actual boundary conditions of the column is essential for successful [...] Read more.
The paper discusses the structural behaviour of concrete-filled steel tube columns (CFT) when applied to the top-down construction method as temporary internal supports for ceilings. Their ultimate capacity to take into account the actual boundary conditions of the column is essential for successful application in construction. The paper presents the full-scale in situ testing of four slender specimens with variable D/t ratios under concentric axial loading. The CFT columns were supported on the previously jacked concrete piles. In addition, detailed finite element numerical models in ABAQUS and PLAXIS computer programs were developed. The models include the nonlinear behaviour of materials and the nonlinear behaviour of soil. The soil–pile–column interaction and impact of the CFT column–pile connection stiffness on global column stability were considered. The numerical model was validated by comparison with the experimental results. In conclusion, the coefficient for the effective buckling length of the studied columns is proposed. Finally, the experimental results of the critical buckling forces were compared with widely used international design codes Eurocode 4-EC4, American standard-ACI and the Australian standard-AS. Full article
(This article belongs to the Section Civil Engineering)
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11 pages, 900 KiB  
Review
Bone Healing Materials in the Treatment of Recalcitrant Nonunions and Bone Defects
by Emérito Carlos Rodríguez-Merchán
Int. J. Mol. Sci. 2022, 23(6), 3352; https://doi.org/10.3390/ijms23063352 - 20 Mar 2022
Cited by 58 | Viewed by 5546
Abstract
The usual treatment for bone defects and recalcitrant nonunions is an autogenous bone graft. However, due to the limitations in obtaining autogenous bone grafts and the morbidity associated with their procurement, various bone healing materials have been developed in recent years. The three [...] Read more.
The usual treatment for bone defects and recalcitrant nonunions is an autogenous bone graft. However, due to the limitations in obtaining autogenous bone grafts and the morbidity associated with their procurement, various bone healing materials have been developed in recent years. The three main treatment strategies for bone defects and recalcitrant nonunions are synthetic bone graft substitutes (BGS), BGS combined with bioactive molecules, and BGS and stem cells (cell-based constructs). Regarding BGS, numerous biomaterials have been developed to prepare bone tissue engineering scaffolds, including biometals (titanium, iron, magnesium, zinc), bioceramics (hydroxyapatite (HA)), tricalcium phosphate (TCP), biopolymers (collagen, polylactic acid (PLA), polycaprolactone (PCL)), and biocomposites (HA/MONs@miR-34a composite coating, Bioglass (BG)-based ABVF-BG (antibiotic-releasing bone void filling) putty). Bone tissue engineering scaffolds are temporary implants that promote tissue ingrowth and new bone regeneration. They have been developed to improve bone healing through appropriate designs in terms of geometric, mechanical, and biological performance. Concerning BGS combined with bioactive molecules, one of the most potent osteoinductive growth factors is bone morphogenetic proteins (BMPs). In recent years, several natural (collagen, fibrin, chitosan, hyaluronic acid, gelatin, and alginate) and synthetic polymers (polylactic acid, polyglycolic acid, polylactic-coglycolide, poly(e-caprolactone) (PCL), poly-p-dioxanone, and copolymers consisting of glycolide/trimethylene carbonate) have been investigated as potential support materials for bone tissue engineering. Regarding BGS and stem cells (cell-based constructs), the main strategies are bone marrow stromal cells, adipose-derived mesenchymal cells, periosteum-derived stem cells, and 3D bioprinting of hydrogels and cells or bioactive molecules. Currently, significant research is being performed on the biological treatment of recalcitrant nonunions and bone defects, although its use is still far from being generalized. Further research is needed to investigate the efficacy of biological treatments to solve recalcitrant nonunions and bone defects. Full article
(This article belongs to the Special Issue Research on Bone Healing Materials)
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13 pages, 2023 KiB  
Article
A Comparative Study of Two Bone Graft Substitutes—InterOss® Collagen and OCS-B Collagen®
by Gaurav Jain, Dylan Blaauw and Steve Chang
J. Funct. Biomater. 2022, 13(1), 28; https://doi.org/10.3390/jfb13010028 - 9 Mar 2022
Cited by 16 | Viewed by 6559
Abstract
Bone is a complex hierarchical tissue composed of organic and inorganic materials that provide structure, support, and protection to organs. However, there are some critical size defects that are unable to regenerate on their own and therefore require clinical repair. Bone graft substitutes [...] Read more.
Bone is a complex hierarchical tissue composed of organic and inorganic materials that provide structure, support, and protection to organs. However, there are some critical size defects that are unable to regenerate on their own and therefore require clinical repair. Bone graft substitutes allow repair by providing a temporary resorbable device. Among the common filler materials that aid in regeneration is hydroxyapatite particles of either animal or human origin which is used to fill or reconstruct periodontal and bony defects in the mouth. However, particulate graft substitutes suffer from localized migration away from the implantation site, necessitating the use of a barrier membrane. In this study, we designed InterOss Collagen, combining bovine hydroxyapatite granules with porcine-skin derived collagen to form a bone filler composite. Physiochemical properties of InterOss Collagen and a commercially available product, OsteoConductive Substitute-Bovine (OCS-B) Collagen, referred to as OCS-B Collagen, were examined. We found two bone graft substitutes to be mostly similar, though InterOss Collagen showed comparatively higher surface area and porosity. We conducted an in vivo study in rabbits to evaluate local tissue responses, percent material resorption and bone formation and showed that the two materials exhibited similar degradation profiles, inflammatory and healing responses following implantation. Based on these results, InterOss Collagen is a promising dental bone grafting material for periodontal and maxillofacial surgeries. Full article
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9 pages, 690 KiB  
Article
Impact of Adjunctive Laser Irradiation on the Bacterial Load of Dental Root Canals: A Randomized Controlled Clinical Trial
by Johannes-Simon Wenzler, Wolfgang Falk, Roland Frankenberger and Andreas Braun
Antibiotics 2021, 10(12), 1557; https://doi.org/10.3390/antibiotics10121557 - 20 Dec 2021
Cited by 16 | Viewed by 5036
Abstract
Successful root canal treatment depends on the adequate elimination of pathogenic bacteria. This study evaluated the effectiveness of a novel 445-nm semiconductor laser in reducing bacteria after chemomechanical root canal treatment. Microbiological specimens from 57 patients were collected after emergency endodontic treatment, in [...] Read more.
Successful root canal treatment depends on the adequate elimination of pathogenic bacteria. This study evaluated the effectiveness of a novel 445-nm semiconductor laser in reducing bacteria after chemomechanical root canal treatment. Microbiological specimens from 57 patients were collected after emergency endodontic treatment, in the following sequence: 1, removal of the temporary filling material; 2, chemomechanical treatment; 3, rinsing with sodium hypochlorite (3%) along with one of three adjuvant protocols (n = 19 in each group). The adjuvant procedures were: (a) sodium hypochlorite rinsing alone (3%); (b) laser irradiation; (c) combined sodium hypochlorite rinsing and laser irradiation. The diode laser was set to 0.59 W in continuous-wave mode (CW) for 4 × 10 s. After the flooding of the root canal with saline, specimens were collected using paper points and analyzed microbiologically. Statistically significant reductions in the bacterial load were observed in all three groups (p < 0.05): 80.5% with sodium hypochlorite rinsing alone and 58.2% with laser therapy. Both results were lower than with the combination of sodium hypochlorite rinsing and 445-nm laser irradiation, at 92.7% (p < 0.05). Additional disinfection of the root canal can thus be achieved with 445-nm laser irradiation after conventional chemical disinfection with sodium hypochlorite solution. Full article
(This article belongs to the Special Issue Antibacterial Treatment in Periodontal and Endodontic Therapy)
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12 pages, 6379 KiB  
Article
The Behavior of Polyurethane Foam-Filled Glass-Fiber-Reinforced Polymer Crossarm Subjected to Lightning Transient Voltage
by Muhammad Syahmi Abd Rahman, Mohd Zainal Abidin Ab Kadir, Muhamad Safwan Abd Rahman, Miszaina Osman, Ungku Anisa Ungku Amirulddin, Shamsul Fahmi Mohd Nor and Noorlina Mohd Zainuddin
Materials 2021, 14(19), 5628; https://doi.org/10.3390/ma14195628 - 28 Sep 2021
Cited by 1 | Viewed by 2706
Abstract
The demand for composite materials in high-voltage electrical insulation is escalating over the last decades. In the power system, the composite glass-fiber-reinforced polymer has been used as an alternative to wood and steel crossarm structures due to its superior properties. As a composite, [...] Read more.
The demand for composite materials in high-voltage electrical insulation is escalating over the last decades. In the power system, the composite glass-fiber-reinforced polymer has been used as an alternative to wood and steel crossarm structures due to its superior properties. As a composite, the material is susceptible to multi-aging factors, one of which is the electrical stress caused by continuous and temporary overvoltage. In order to achieve a better insulation performance and higher life expectancy, the distribution of the stresses should firstly be studied and understood. This paper focuses on the simulation work to better understand the stress distribution of the polyurethane foam-filled glass-fiber-reinforced polymer crossarm due to the lightning transient injection. A finite-element-based simulation was carried out to investigate the behavior of the electric field and voltage distribution across the sample using an Ansys Maxwell 3D. Electrical stresses at both outer and inner surfaces of the crossarm during the peak of lightning were analyzed. Analyses on the electric field and potential distribution were performed at different parts of the crossarm and correlated to the physical characteristics and common discharge location observed during the experiment. The results of the electric field on the crossarm indicate that both the outer and internal parts of the crossarm were prone to high field stress. Full article
(This article belongs to the Topic Electromaterials for Environment & Energy)
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