Bone Tissue Level Research Articles

[Translated article] Approach to the elderly patient with vertebral fracture due to bone fragility

Osteoporosis is a metabolic and systemic disease characterised by alterations at the level of bone tissue with loss of bone mineral density, changes in microarchitecture, mineralisation and remodelling that determine greater bone fragility and risk of fracture.Falls in the elderly are a risk factor closely related to fragility fractures and numerous studies demonstrate this relationship.Vertebral fractures are a major cause of morbidity and mortality. The epidemiology differs from osteoporotic fractures at other skeletal sites, as only one-third are clinically recognised. In the elderly, the approach to osteoporotic vertebral fracture involves comprehensive evaluation of the patient, since it is both a cause and a consequence of multiple geriatric syndromes. This fracture, in its acute phase and subsequently, can lead to destabilisation of other organs and systems of the elderly, medical complications at different levels, functional deterioration, dependence, and even the need for institutionalisation.Therefore, it is important to carry out a multiple assessment of patients with vertebral fractures, addressing not only the history and risk factors of osteoporosis, but also those factors that lead to falls, as well as a comprehensive geriatric assessment and the complications closely associated with it.In this chapter we address each of these aspects that are necessary in the individual and multidimensional approach to the elderly patient with vertebral fracture due to bone fragility.

Beyond bone volume: Understanding tissue-level quality in healing of maxillary vs. femoral defects

Currently, principles of tissue engineering and implantology are uniformly applied to all bone sites, disregarding inherent differences in collagen, mineral composition, and healing rates between craniofacial and long bones. These differences could potentially influence bone quality during the healing process. Evaluating bone quality during healing is crucial for understanding local mechanical properties in regeneration and implant osseointegration. However, site-specific changes in bone quality during healing remain poorly understood. In this study, we assessed newly formed bone quality in sub-critical defects in the maxilla and femur, while impairing collagen cross-linking using β-aminopropionitrile (BAPN). Our findings revealed that femoral healing bone exhibited a 73 % increase in bone volume but showed significantly greater viscoelastic and collagen changes compared to surrounding bone, leading to increased deformation during long-term loading and poorer bone quality in early healing. In contrast, the healing maxilla maintained equivalent hardness and viscoelastic constants compared to surrounding bone, with minimal new bone formation and consistent bone quality. However, BAPN-impaired collagen cross-linking induced viscoelastic changes in the healing maxilla, with no further changes observed in the femur. These results challenge the conventional belief that increased bone volume correlates with enhanced tissue-level bone quality, providing crucial insights for tissue engineering and site-specific implant strategies. The observed differences in bone quality between sites underscore the need for a nuanced approach in assessing the success of regeneration and implant designs and emphasize the importance of exploring site-specific tissue engineering interventions. Statement of significanceAccurate measurement of bone quality is crucial for tissue engineering and implant therapies. Bone quality varies between craniofacial and long bones, yet it's often overlooked in the healing process. Our study is the first to comprehensively analyze bone quality during healing in both the maxilla and femur. Surprisingly, despite significant volume increase, femur healing bone had poorer quality compared to the surrounding bone. Conversely, maxilla healing bone maintained consistent quality despite minimal bone formation. Impaired collagen diminished maxillary healing bone quality, but had no further effect on femur bone quality. These findings challenge the notion that more bone volume equals better quality, offering insights for improving tissue engineering and implant strategies for different bone sites.

Horizontal and vertical deviation caused by tightening torque on polyether ether ketone scan body in bone level versus tissue level implant: In vitro study

Horizontal and vertical deviation caused by tightening torque on polyether ether ketone scan body in bone level versus tissue level implant: In vitro study

Exploring the multicomponent synergy mechanism of Zuogui Wan on postmenopausal osteoporosis by a systems pharmacology strategy.

To explore the multi-component synergistic mechanism of Zuogui Wan (, ZGW) in treating postmenopausal osteoporosis (PMOP). The main components and target genes of ZGW were screened via the Traditional Chinese Medicine Systems Pharmacology (TCMSP). In addition, the target gene sets of PMOP were derived from the GeneCards and Online Mendelian Inheritance in Man databases. The search tool for recurring instances of neighbouring genes (STRING) 11.0 software was used to analyze the interaction among intersecting genes. Cytoscape 3.6.1 software and the Matthews correlation coefficient (MCC) algorithm were used to screen the core genes. Fifty Sprague-Dawley female rats were randomly divided into the sham-operated (Sham) group and the four ovariectomized (OVX) subgroups. Rats subjected to Sham or OVX were administered with the vehicle (OVX, 1 mL water/100 g weight), 17β-estradiol (E2, 50 μg·kg-1·d-1), and lyophilized powder of ZGW at a low dose of 2.3 (ZGW-L) and high dose of 4.6 (ZGW-H) g·kg-1·d-1 for three months. The bone density and bone strength were assessed using dual-energy X-ray and three-point bending tests, respectively. Furthermore, enzyme-linked immun-osorbent assay, Hematoxylin-eosin staining, and western blot analysis were used to determine the potential pharmacological mechanisms of action of ZGW in PMOP. A total of 117 active compounds of ZGW were screened from the TCMSP. Furthermore, 108 intersecting genes of drugs and diseases were identified. Using STRING software and the MCC algorithm, ten core genes, including C-X-C chemokine living 8 (CXCL8), C-C chemokine receptor type 2 (CCR2), alpha-2a active receptor (ADRA2A), melatonin receptor type 1B (MTNR1B), and amyloid-beta A4 protein (APP), were identified. The anti-osteoporosis regulation network of ZGW was constructed using the Cytoscape software. The animal experiments demonstrated that ZGW groups significantly reduced the serum levels of β-C-terminal telopeptide of type I collagen (β-CTX) and increased serum levels of bone-specific alkaline phosphatase (BALP) (P < 0.05, P < 0.01). The OVX group exhibited a significant decrease in bone mineral density and bone strength compared with the Sham group (P < 0.01). Moreover, treatment with ZGW resulted in increased trabecular thickness, improved arrangement of trabecular structure, and reduced empty bone lacunae. Furthermore, treatment with ZGW significantly increased the protein expression of CXCL8, ADRA2A, and CCR2 (P < 0.05, P < 0.01), and significantly decreased the protein expression of Runx2 (P < 0.01). Furthermore, the ZGW and E2 groups demonstrated significantly increased BMD (P < 0.05, P < 0.01), improved bone strength (P < 0.05, P < 0.01), reduced expression of CXCL8, ADRA2A, and CCR2, and increased runt-related transcription factor 2 levels in bone tissue (P < 0.05, P < 0.01) compared with the OVX group. However, there were no significant differences in MTNR1B and APP expression among the groups. ZGW shows synergistic mechanisms in PMOP through multiple components, targets, and pathways.

Abordaje del adulto mayor con fractura vertebral por fragilidad ósea

Osteoporosis is a metabolic and systemic disease characterized by alterations at the level of bone tissue with loss of bone mineral density, changes in microarchitecture, mineralization and remodeling that determine greater bone fragility and risk of fracture.Falls in the elderly are a risk factor closely related to fragility fractures and numerous studies demonstrate this relationship.Vertebral fractures are a major cause of morbidity and mortality. The epidemiology differs from osteoporotic fractures at other skeletal sites, as only one-third are clinically recognized. In the elderly, the approach to osteoporotic vertebral fracture involves comprehensive evaluation of the patient, since it is both a cause and a consequence of multiple geriatric syndromes. This fracture, in its acute phase and subsequently, can lead to destabilization of other organs and systems of the elderly, medical complications at different levels, functional deterioration, dependence, and even the need for institutionalization.Therefore, it is important to carry out a multiple assessment of patients with vertebral fractures, addressing not only the history and risk factors of osteoporosis, but also those factors that lead to falls, as well as a comprehensive geriatric assessment and the complications closely associated with it.In this chapter we address each of these aspects that are necessary in the individual and multidimensional approach to the elderly patient with vertebral fracture due to bone fragility.

MiR-144-5p and miR-21-5p do not drive bone disease in a mouse model of type 1 diabetes mellitus.

The increased risk of fractures in patients with type 1 diabetes mellitus (T1DM) is nowadays well recognized. However, the exact mechanism of action of diabetic bone disease has not been fully elucidated. MicroRNAs (miRNAs) are gene regulators that operate post-transcriptionally and have been implicated in the development of various metabolic disorders including T1DM. Previous studies have implicated a role for miR-144-5p and miR-21-5p, which are involved in controlling oxidative stress by targeting Nrf2, in T1DM. To date, it is unclear whether miR-144-5p and miR-21-5p affect bone health in T1DM. Thus, this study aimed to investigate the influence of miR-144-5p and miR-21-5p knockdown in the development of bone disease in T1DM male mice. Therefore, T1DM was induced in 10-wk-old male mice using streptozotocin (STZ). One week later, after development of hyperglycemia, antagomir-144-5p and antagomir-21-5p or their non-targeting control were administered at 10mg/kg BW once a week until the end of the experiment. At 14wk of age, glucose levels, bone, and fat mass were analyzed. The results revealed that treating T1DM male mice with antagomir-144-5p and antagomir-21-5p did not protect against diabetes development or bone loss, despite the successful downregulation of the miRNAs and the normalization of Nrf2 mRNA levels in bone tissue. Histological and serological parameters of bone formation or resorption were not altered by the antagomir treatment. Finally, we measured the expression of miRNA-144-5p or miRNA-21-5p in the serum of 30 individuals with T1DM and compared them to non-diabetic controls, but did not find an altered expression of either miRNA. In conclusion, the knockdown of miR-144-5p and miR-21-5p does not affect STZ-induced diabetes development or loss of bone mass in male mice. However, it does normalize expression of the anti-oxidant factor Nrf2 in diabetic bone tissue.

Icariin ameliorates osteoporosis in ovariectomized rats by targeting Cullin 3/Nrf2/OH pathway for osteoclast inhibition

Osteoporosis, characterized by low bone mass and bone microarchitecture breakdown, has become a growing public health problem. The increase in oxidative stress could lead to an imbalance between osteoblasts-mediated osteogenesis and osteoclast-mediated bone resorption, which gives rise to osteoporosis. Nrf2 is a master transcription factor that regulates oxidative stress and has recently been reported to take part in the development of osteoporosis. Icariin, a leading active flavonoid in herbal Epimedium pubescens, has significant antioxidant activity in and is widely applied for treating bone diseases. In this study, we aimed to explore the effect of icariin on osteoclastogenesis and its potential mechanism from the perspective of oxidative stress inhibition, using ovariectomized (OVX) rats and RANKL-induced RAW264.7 cells. Our results demonstrated that icariin-treated OVX rats exhibited higher bone density, fewer tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, and lower ROS levels in bone tissues than vehicle-treated OVX rats. Also, icariin suppressed osteoclast differentiation and inhibited the expression of osteoclastogenesis-related genes, such as NFATc1, Ctsk, Trap, and c-Fos, in RANKL-induced RAW264.7 cells. Icariin also reduced intracellular ROS levels by increasing the expression of nuclear Nrf2 and HO-1. Further mechanistic studies showed icariin inhibited Cullin 3 expression and could delay Nrf2 degradation by reducing the ubiquitination of endogenous Nrf2 in RANKL-stimulated RAW264.7 cells, and these effects were markedly reversed by cullin three overexpression. These findings suggest icariin alleviated osteoporosis by suppressing osteoclastogenesis via targeting the Cullin 3/Nrf2/OH signaling pathway. Our study implied that icariin may be a potential candidate to treat osteoporosis.

Effect of implant type on the stability of cantilever fixed dental prostheses: An invitro study.

To simulate the replacement of a premolar with an implant-supported cantilever fixed dental prosthesis (ICFDP) and how the fracture load is affected by implant type, positioning within the zirconia blank, and aging protocol. Seventy-two ICFDPs were designed either within the enamel- or dentin layer of a 4Y-PSZ blank for bone-level and tissue-level titanium-zirconium implants. Fracture load was obtained on the cantilever at baseline (no aging) or after aging in a chewing simulator with the load applied within the implant axis (axial aging) or on the cantilever (12 groups with n = 6). A three-way ANOVA was applied (α = .05). A three-way ANOVA revealed a significant effect on fracture load values of implant type (p = .006) and aging (p < .001) but not for the position within the zirconia blank (p = .847). Fracture load values significantly increased from baseline bone level (608 ± 118 N) and tissue level (880 ± 293 N) when the implants were aged axially, with higher values for tissue level (1065 ± 182 N) than bone level (797 ± 113 N) (p < .001). However, when the force was applied to the cantilever, fracture load values decreased significantly for tissue-level (493 ± 70 N), while values for bone-level implants remained stable (690 ± 135 N). For ICFDPs, the use of bone-level implants is reasonable as catastrophic failures are likely to be restricted to the restoration, whereas with tissue-level implants, the transmucosal portion of the implant is susceptible to deformation, making repair more difficult.

АНАЛИЗ НАПРЯЖЕННО-ДЕФОРМИРОВАННОГО СОСТОЯНИЯ КОСТНОЙ ТКАНИ ПРИ ОРТОПЕДИЧЕСКОМ ЛЕЧЕНИИ МОСТОВИДНЫМИ ПРОТЕЗАМИ С ОПОРОЙ НА ДЕНТАЛЬНЫЕ ИМПЛАНТАТЫ

Currently, structures based on dental implants are increasingly used for orthopedic treatment of partial and complete tooth loss, which can significantly improve the effectiveness of treatment and the quality of life of patients. To date, a large number of implantation systems are known, which are quite well studied, but so far, a number of issues remain unresolved, and the most important of them is the choice of the method of fixation of implantation prostheses. The main task in orthopedic treatment based on dental implants is to maintain a stable level of bone tissue, and, as a result, the long-term prospects for the functioning of the implant and the entire structure. There are two main types of fixations of such prostheses: screw and cement, but there is still no specificity in the choice of indications for them. In this study, based on mathematical modeling data, an analysis of the stress-strain state of bone tissue in the area of implants installed at different angles to each other was carried out. Mathematical models of screw-fixed bridges supported by two implants located strictly parallel to each other and at angles from 2о to 10о have been developed (conical and planar types of connection of implant platforms with abutments have been studied). The analysis of the maximum equivalent Mises stresses occurring inside the structure itself is also carried out. Stress localization zones under vertical load have been identified. The critical angles of implant divergence have been determined, which determine the indications for the use of screw-type fixation of bridges.

Evaluation of Porcine Collagen Membranes Used with Guided Bone Regeneration for Critical Defects: A Histological, Histomorphometric, Immunohistochemical, and Inflammatory Profile Analysis.

The objective of this study was to compare the effectiveness of two porcine collagen membranes of different origin used for guided bone regeneration procedures. Resorbable collagen membrane from porcine dermis (Bio-Gide, Geistlich Pharma AG, Wolhusen, Switzerland) and resorbable collagen membrane from porcine pericardium (Jason, Institut Straumann AG, Peter Merian-Weg, Switzerland) were evaluated; histological, histometric, immunohistochemical, and inflammatory profile analyses were performed. The study was carried out on critical defects created in the calvaria of 72 rats (Rattus norvegicus albinus, Wistar variety) divided into three groups: coagulum group (Co), porcine pericardium group (JS), and porcine collagen group (BG). The defects were filled with clot, over which the membranes were placed. The animals were euthanized 7, 15, 30, and 60 days after surgery. The Shapiro-Wilk test was used to assess data distribution. Analysis of variance (ANOVA) and the Bonferroni multiple comparison test were used to compare the differences across the mean values of the variables. Nonparametric tests, Mann-Whitney and Wilcoxon W, were used for the quantitative analysis of the inflammatory profile. A significance level of 5% (p < 0.05) was adopted with a confidence interval of 95%. SPSS software version 2.0 was used. A total of 1,008 analyses were performed on 288 histological slides. It was noted that both types of collagen membranes used in this study were effective for the guided bone regeneration procedure, with a greater proportion and thickness of bone formation among recipients of the BG (735 points, p = 0.021). This membrane also had greater permeability (62.25). The animals in the JS group, which received the porcine pericardial membrane, showed early and accelerated bone formation from early bone tissue, milder osteopontin and osteocalcin levels, and greater inflammatory reaction (86.4). The collagen membrane from porcine dermis demonstrated a more orderly and physiological repair process, while the porcine pericardial membrane presented a more accelerated repair process that did not remain constant over time.

ОСТЕОПЕНИЯ КАК ПРОЯВЛЕНИЕ ИДИОПАТИЧЕСКОЙ ГИПЕРКАЛЬЦИУРИИ У ДЕТЕЙ

Idiopathic hypercalciuria (IH) can lead to the development of osteopenia and osteoporosis in childhood. Vitamin D and its receptor, encoded by the VDR gene, play a major role in maintaining normal calcium levels in bone tissue. The purpose of the study: to study the state of bone mineral density in children with idiopathic hypercalciuria and the association of vitamin D receptor (VDR) gene polymorphisms with osteopenia. Materials and methods. The study included 35 children with IH aged 5 to 17 years with a history of fractures and/or decompensated caries. The children were subjected to X-ray densitometry to calculate the Z score in the lumbar spine and proximal femurs. A group of children with IH (n=20) underwent a study of the level of 25-OH vitamin D in blood plasma and a genetic study for the presence in genetic polymorphisms of the VDR gene: BsmI Polymorphism IVS10+283G&gt;A, A-3731G (Cdx2), FokI Polymorphism; Ex4+4T&gt;C. Results. A decrease in BMD was detected in 68.6% of children with IH, while 2 patients aged 15 and 17 years had signs of osteoporosis. The homozygous Ex4+4 CC genotype of the VDR (Fokl) gene was significantly more common in patients with idiopathic hypercalciuria. For the remaining genotypes of the VDR enzyme gene, no statistically significant differences could be detected (p&gt;0.05). Conclusion. Idiopathic hypercalciuria in children often leads to a decrease in bone mineral density, which should be taken into account when treating children with this pathology. A genetic predictor of osteopenia in children with IH may be the carriage of the homozygous genotype (rare allele) Ex4+4 CC of whose VDR (Fokl) gene, the study can be used for early diagnosis and prevention of the development of osteoporosis.

Pre-treatment bone turnover does not influence the level of the response to alendronate in postmenopausal osteoporosis at the bone tissue level.

The main effect of anti-resorptive agents such as bisphosphonates is a reduction of bone resorption, with a consequent marked decrease of bone turnover. This post-hoc analysis investigated the changes of histomorphometric parameters of bone turnover after alendronate (ALN), according to the baseline turnover. Ninety postmenopausal women underwent a transiliac bone biopsy before and after 6 (n = 44) or 12 (n = 46) months of treatment with ALN (70 mg/week). The dynamic parameters reflecting the bone formation and bone turnover were mineralizing surface (MS/BS; %), bone formation rate (BFR/BS; μm3/μm2/d), and activation frequency (Ac.f; /yr). Biochemical markers sPINP and the sCTX were assessed before treatment and after 3, 6, and 12 months. Subjects were divided into quartiles based on the baseline values of BFR/BS. At baseline, MS/BS and Ac.f were significantly different (p < 0.0001) among the BFR quartiles. sCTX and sP1NP were not significantly different among quartiles. After ALN treatment, MS/BS was not significantly different among quartiles but Ac.f remained significantly lower in the first quartile compared to the third and fourth ones (p < 0.03). The absolute value of the difference between pre- and post-treatment significantly correlated with the baseline BFR/BS but when expressed in percent of the baseline value, the magnitude of the diminutions of MS/BS, Ac.f, sCTX, and sP1NP was similar in the four baseline BFR quartiles. The percentage response to ALN appeared independent of the baseline level of bone turnover. After treatment, the bone turnover tended to be similar in all BFR quartiles. This analysis investigated the influence of baseline turnover measured by bone histomorphometry on the effect of alendronate. When expressed in percent of pre-treatment values, the decreases of histomorphometric parameters and biochemical markers of bone turnover were independent of the baseline turnover.

Microbiological characterization of a population affected by periodontitis with different levels of bone health

ntroduction: Both osteoporosis and periodontitis are diseases characterized by deficits at the level of bone tissue, where bone resorption exceeds neo-formation, resulting in bone loss. Materials and methods: In the context of a monocentric cross-sectional observational study carried out through the collaboration between the University of Florence and the private dentistry institute Excellence Dental Network, 110 subjects affected by periodontitis were recruited. Of these, 71 were also affected by osteoporosis or osteopenia and 39 were not osteoporotic or osteopenic. Data were collected on oral microbiota, oral health and bone health. Results: The collected data reveal a population of frail subjects in terms of fracture risk. The most common forms of periodontitis were essentially chronic in nature, and mainly of a moderate or even severe type, with high gingival recession and periodontal pocket depth values. The microbial species associated with Socransky's red and orange complexes showed concentration values nearly always above 10³ copies/mL. Conclusions: The relationship between osteoporosis and periodontitis still needs to be explored in depth. Data from our analyses are certainly interesting and provide a basis for designing further studies in larger populations. KEY WORDS: Periodontal disease, bone disease, oral microbiota.

RETROSPECTIVE ANALYSIS OF THE DEGREE OF REDUCTION OF PERI-IMPLANT BONE TISSUE DURING IMMEDIATE AND DELAYED DENTAL IMPLANTATION PROTOCOLS

The article presents a comparative analysis of the periimplant bone tissue level reduction indicator in parallel with the study of the success and survival levels of implants installed according to the protocols of immediate, early and delayed implantation with the search for possible statistical or trend associations between the studied parameters described in the preselected pool of scientific works. The purpose of the study is to analyze the differences in the change in periimplant bone tissue reduction indicators under the conditions of implementation of immediate and delayed implantation protocols, as criteria for its prognosis and assessment of success in the process of remote monitoring. Research materials and methods. The search for relevant scientific publications was carried out using the Google Academy search engine, ensuring the ranking of the obtained results according to the criteria of research depth, the completeness of the correspondence of keywords to the title and content of the abstracts of publications, as well as the number of citations in the structure of previously conducted systematic reviews and meta-analyses. The grouping of the results and the assessment of the level and significance of statistical dependencies between the separated parameters of the study were carried out in the Microsoft Excel 2019 table editor software (Microsoft Office 2019). Research results and their discussion. The level of bone tissue reduction in the peri-implant area is one of the determining criteria for the success of installed dental implants in the immediate and remote periods of monitoring, which were previously proposed by many domestic and foreign authors. Existing methods of registering the decrease in the vertical parameters of the bone ridge adjacent to the surface of installed titanium intraosseous supports provide opportunities not only for the numerical calculation of the difference in indicators at different periods of observation, but also for their quantification in the form of calculating the volume loss of bone, its circular reduction, visualization of the geometry of existing saucer-like defects. The value of the index of loss of bone tissue in the periimplant area as a criterion for the success of implantation also increases in cases of complex interpretation of its changes with a number of other studied parameters, such as the cumulative index of survival and success of implants, the relative risk of various forms of complications, statistical associations with potentially determining factors of influence. It is the complex approach to the interpretation of the registered differences between the indicators of the reduction of the level of periimplant bone tissue in the cases of implementation of the protocols of immediate and delayed implantation with the search for possible associations between this criterion and a number of potentially influential factors that ensured the detailed analysis of previously published data. Conclusions. As a result of a detailed analysis, it was possible to establish that the data of previously conducted studies devoted to the comparison of clinical criteria for the effectiveness of the implementation of immediate and other protocols of dental implantation do not allow formulating an unequivocal conclusion regarding the pronounced difference of the investigated indicators during different periods of observation.

Pathophysiology and Management of Primary Osteoporosis: A Narrative Literature Review

The pathophysiology of primary osteoporosis primarily involves changes at the cellular and bone tissue levels. This process involves an imbalance between the activity of bone-destroying cells (osteoclasts) and bone-constructing cells (osteoblasts). Osteoclasts are responsible for the resorption of old and damaged bone tissue, while osteoblasts build new bone. In osteoporosis, osteoclast activity increases and osteoblasts decrease, resulting in loss of bone mass. Treatment of primary osteoporosis involves a holistic approach that includes lifestyle changes, use of medications, and fracture prevention. The main goal of management is to slow down the decline in bone density, prevent bone fractures, and improve the quality of life of sufferers. Increasing your intake of calcium and vitamin D, as well as regular physical exercise, can help maintain bone mass. Meanwhile, drugs such as bisphosphonates and teriparatide can be used to inhibit bone breakdown or stimulate new bone formation.

Improvement of selective laser melting regimes for the fabrication of Ti–6Al–4V porous structures for medical applications

This article describes approaches to the optimization of regimes of selective laser melting (SLM) used in the fabrication of porous materials from medical grade Ti–6Al–4V alloy with thin structural elements and a low level of defect porosity. Improved fusion of thin elements based on SLM regimes is achieved due to a significant decrease in the distance between laser passes (from 0.11 to 0.04–0.05 mm). Moreover, the balance between the laser energy density and building rate is compensated by changing the laser speed and laser power. The results of the study of defect porosity and hardness of samples fabricated according to experimental SLM regimes allowed three promising sets of parameters to be defined. One was selected for studying mechanical properties in comparison with the reference SLM regime. In the aims of this study, the samples were developed and fabricated using the structures of rhombic dodecahedron and Voronoi types with a porosity of 70–75 %. The decrease in defect porosity was established at ≈1.8 % to 0.6 %, depending on the SLM regime. This promotes a significant increase in strength properties of the material, including an increase in the yield strength of rhombic dodecahedron from 76 to 132 MPa and the Voronoi structure from 66 to 86 MPa. The low Young module (1–2 GPa) remains, corresponding to the rigidity level of spongy bone tissue.

Prevalence of peri-implantitis after alveolar ridge preservation at periodontitis and nonperiodontitis extraction sites: A retrospective cohort study.

Periodontitis is the main indication for dental extraction and often leads to peri-implantitis (PI). Alveolar ridge preservation (ARP) is an effective means of preserving ridge dimensions after extraction. However, whether PI prevalence is lower after ARP for extraction after periodontitis remains unclear. This study investigated PI after ARP in patients with periodontitis. This study explored the 138 dental implants of 113 patients. The reasons for extraction were categorized as periodontitis or nonperiodontitis. All implants were placed at sites treated using ARP. PI was diagnosed on the basis of radiographic bone loss of ≥3 mm, as determined through comparison of standardized bitewing radiographs obtained immediately after insertion with those obtained after at least 6 months. Chi-square and two-sample t testing and generalized estimating equations (GEE) logistic regression model were employed to identify risk factors for PI. Statistical significance was indicated by p < 0.05. The overall PI prevalence was 24.6% (n = 34). The GEE univariate logistic regression demonstrated that implant sites and implant types were significantly associated with PI (premolar vs. molar: crude odds ratios [OR] = 5.27, 95% confidence intervals [CI] = 2.15-12.87, p = 0.0003; bone level vs. tissue level: crude OR = 5.08, 95% CI = 2.10-12.24; p = 0.003, respectively). After adjustment for confounding factors, the risks of PI were significantly associated with implant sites (premolar vs. molar: adjusted OR [AOR] = 4.62, 95% CI = 1.74-12.24; p = 0.002) and implant types (bone level vs. tissue level: AOR = 6.46, 95% CI = 1.67-25.02; p = 0.007). The reason for dental extraction-that is, periodontitis or nonperiodontitis-was not significantly associated with PI. ARP reduces the incidence of periodontitis-related PI at extraction sites. To address the limitations of our study, consistent and prospective randomized controlled trials are warranted.

Biomimetic Fibers Derived from an Equidistant Micropillar Platform Dictate Osteocyte Fate via Mechanoreception.

It is a big challenge to design a biomimetic physical microenvironment with greater similarity to in vivo tissue to observe real cell behaviors. We established a novel cell culture platform based on patterned equidistant micropillars with stiff and soft stiffnesses to mimic the changes that happened in the transition from normal to osteoporotic disease. We first demonstrated that the soft micropillar substrate decreased osteocyte synaptogenesis through synaptogyrin 1 and that this decrease was accompanied by impairment of cell mechanoperception and a decrease in cellular cytoskeletal rearrangement. We then found that the soft equidistant micropillar substrate reduced the osteocyte synaptogenesis mainly via the inactivation of Erk/MAPK signaling. We finally found that soft micropillar substrate-mediated synaptogenesis impacted the cell-to-cell communication and matrix mineralization of osteocytes. Taken together, this study provides evidence of cellular mechanical responses that are much more similar to those of real osteocytes at the bone tissue level.

Protective effects of resveratrol on permethrin-induced fetotoxicity in rats

Synthetic pyrethroid insecticides have been widely used for years to prevent harmful effects of insects and control disease vectors. In this study, the effects of resveratrol against the potential toxicity of permethrin, an effective pyrethroid derivative, on the fetus were investigated. Accordingly, Wistar female rats were divided into four groups as Control, Sham, Permethrin, and Permethrin + Resveratrol. Lung, liver, kidney and small intestine of developing fetuses were evaluated histopathologically. Also, Bone Morphogenetic Protein-4 (BMP-4) in bone tissue development and Fibroblast Growth Factor-1 (FGF-1) expressions in lung were examined immunohistochemically. All structures in the Control and Sham groups were normal. Permethrin caused epithelial damage, regression in bronchial and primitive alveolar development in the lung; congestion, edema and sinusoidal dilatation around the central vein in the liver; tubular epithelial degeneration, regression in glomeruli and tubule formation in the kidney; epithelial degeneration and irregularity in the villus structure in the small intestine. Immunohistochemical results indicated that permethrin administration decreased BMP-4 levels in bone tissue and FGF-1 levels in lung. Resveratrol application was found to greatly alleviate histopathological and immunohistopathological variability in all tissues. Oral consumption of permethrin by pregnant rats caused growth retardation and tissue damage in many different tissues in offspring. Intake of resveratrol during pregnancy showed protective effects against fetotoxicity caused by permethrin.

Microstructural and cellular characterisation of the subchondral trabecular bone in human knee and hip osteoarthritis using synchrotron tomography

It is unclear if different factors influence osteoarthritis (OA) progression and degenerative changes characterising OA disease in hip and knee. We investigated the difference between hip OA and knee OA at the subchondral bone (SCB) tissue and cellular level, relative to the degree of cartilage degeneration. Bone samples were collected from 11 patients (aged 70.4±10.7years) undergoing knee arthroplasty and 8 patients (aged 62.3±13.4years) undergoing hip arthroplasty surgery. Trabecular bone microstructure, osteocyte-lacunar network, and bone matrix vascularity were evaluated using synchrotron micro-CT imaging. Additionally, osteocyte density, viability, and connectivity were determined histologically. The associations between severe cartilage degeneration and increase of bone volume fraction (%) [-8.7, 95% CI (-14.1, -3.4)], trabecular number (#/mm) [-1.5, 95% CI (-0.8, -2.3)], osteocyte lacunar density (#/mm3) [4714.9; 95% CI (2079.1, 7350.6)] and decrease of trabecular separation (mm) [-0.07, 95% CI (0.02, 0.1)] were found in both knee and hip OA. When compared to knee OA, hip OA was characterised by larger (µm3) but less spheric osteocyte lacunae [47.3; 95% CI (11.2, 83.4), -0.04; 95% CI (-0.06, -0.02), respectively], lower vascular canal density (#/mm3) [-22.8; 95% CI (-35.4, -10.3)], lower osteocyte cell density (#/mm2) [-84.2; 95% CI (-102.5, -67.4)], and less senescent (#/mm2) but more apoptotic osteocytes (%) [-2.4; 95% CI (-3.6, -1.2), 24.9; 95% CI (17.7, 32.1)], respectively. SCB from hip OA and knee OA exhibits different characteristics at the tissue and cellular levels, suggesting different mechanisms of OA progression in different joints.