Bone Tissue Level Research Articles

Staphylococcus aureus Infection Induces the Production of the Neutrophil Chemoattractants CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7 by Murine Osteoblasts.

Staphylococcus aureus is the principal causative agent of osteomyelitis, a serious bacterial infection of bone that is associated with progressive inflammatory damage. Bone-forming osteoblasts have increasingly been recognized to play an important role in the initiation and progression of detrimental inflammation at sites of infection and have been demonstrated to release an array of inflammatory mediators and factors that promote osteoclastogenesis and leukocyte recruitment following bacterial challenge. In the present study, we describe elevated bone tissue levels of the potent neutrophil-attracting chemokines CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7 in a murine model of posttraumatic staphylococcal osteomyelitis. RNA sequencing (RNA-Seq) gene ontology analysis of isolated primary murine osteoblasts showed enrichment in differentially expressed genes involved in cell migration and chemokine receptor binding and chemokine activity following S. aureus infection, and a rapid increase in the expression of mRNA encoding CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7, in these cells. Importantly, we have confirmed that such upregulated gene expression results in protein production with the demonstration that S. aureus challenge elicits the rapid and robust release of these chemokines by osteoblasts and does so in a bacterial dose-dependent manner. Furthermore, we have confirmed the ability of soluble osteoblast-derived chemokines to elicit the migration of a neutrophil-like cell line. As such, these studies demonstrate the robust production of CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7 by osteoblasts in response to S. aureus infection, and the release of such neutrophil-attracting chemokines provides an additional mechanism by which osteoblasts could drive the inflammatory bone loss associated with staphylococcal osteomyelitis.

Comprehensive Associations between Acidosis and the Skeleton in Patients with Kidney Disease.

Renal osteodystrophy (ROD) contributes substantially to morbidity in CKD, including increased fracture risk. Metabolic acidosis (MA) contributes to the development of ROD, but an up-to-date skeletal phenotype in CKD-associated acidosis has not been described. We comprehensively studied associations between acidosis and bone in patients with CKD using advanced methods to image the skeleton and analyze bone-tissue, along with biochemical testing. Cross-sectionally, acidosis was associated with higher markers of bone remodeling and female-specific impairments in cortical and trabecular bone quality. Prospectively, acidosis was associated with cortical expansion and trabecular microarchitectural deterioration. At the bone-tissue level, acidosis was associated with deficits in bone mineral content. Future work investigating acidosis correction on bone quality is warranted. Renal osteodystrophy is a state of impaired bone quality and strength. Metabolic acidosis (MA) is associated with alterations in bone quality including remodeling, microarchitecture, and mineralization. No studies in patients with CKD have provided a comprehensive multimodal skeletal phenotype of MA. We aim to describe the structure and makeup of bone in patients with MA in the setting of CKD using biochemistry, noninvasive imaging, and histomorphometry. The retrospective cross-sectional analyses included 180 patients with CKD. MA was defined as bicarbonate ≤22 mEq/L. We evaluated circulating bone turnover markers and skeletal imaging with dual energy x-ray absorptiometry and high-resolution peripheral computed tomography. A subset of 54 participants had follow-up. We assessed associations between baseline and change in bicarbonate with change in bone outcomes. Histomorphometry, microCT, and quantitative backscatter electron microscopy assessed bone biopsy outcomes in 22 participants. The mean age was 68±10 years, 54% of participants were male, and 55% were White. At baseline, acidotic subjects had higher markers of bone turnover, lower areal bone mineral density at the radius by dual energy x-ray absorptiometry, and lower cortical and trabecular volumetric bone mineral density and impaired trabecular microarchitecture. Over time, acidosis was associated with opposing cortical and trabecular effects: cortical expansion but trabecular deterioration. Bone-tissue analyses showed reduced tissue mineral density with increased heterogeneity of calcium distribution in acidotic participants. MA is associated with multiple impairments in bone quality. Future work should examine whether correction of acidosis improves bone quality and strength in patients with CKD.

SPON2 promotes the bone metastasis of lung adenocarcinoma via activation of the NF-κB signaling pathway.

Bone metastasis severely affects the life span and quality of life of survivors of lung adenocarcinoma (ADC). There is a pressing need to identify viable biomarkers for this incurable, fatal disease. Spondin-2 (SPON2) has been reported to be involved in metastasis and cancer progression, but its role in bone metastasis in patients with lung ADC has rarely been studied. Here, we showed that the upregulation of SPON2 increased the migration, invasion, and epithelial-to-mesenchymal transition of ADC cells in vitro, whereas silencing SPON2 repressed these processes. Consistently, silencing SPON2 significantly reduced the bone metastasis of ADC cells in vivo. Mechanistically, SPON2 activated the nuclear factor-κB (NF-κB) signaling pathway and increased the expression levels of MMP2 and MMP9. Blocking NF-κB using an inhibitor attenuated the SPON2-induced migration and invasion of ADC cells. In addition, we found that SPON2 expression levels were increased in metastatic bone tissues compared to primary ADC tissues. The upregulation of SPON2 was positively correlated with MMP2 and MMP9 expression levels in metastatic bone tissues. In conclusion, these results illustrate that SPON2 plays a key role in ADC by activating the NF-κB pathway to promote bone metastasis, which suggests that it may be a target for future drug development.

Innovative methods and developments in oral care. 3D planning in oral and maxillofacial surgery

With the use of cone beam computed tomography, intraoral scanning and 3D stereophotogrammetry, a virtual 3D head model of a patient can be reconstructed with image fusion. In this way, the malposition, deficiency and other anomalies at the level of bone, dentition and soft tissue can be quantified objectively. The desired position of the dentition, occlusion and soft tissue in the facial profile can be virtually drawn in and used as a guideline for treatment planning. Based on the principle of backward planning, it is possible to determine what repositioning of the jaw is required, where there is a need for bone augmentation and how many dental implants are necessary to obtain the desired treatment outcome. From this perspective, 3D treatment planning has become a treatment standard for the 4 clinical pillars supporting oral and maxillofacial surgery, specifically orthognathic surgery, implantology, craniofacial surgery and head & neck oncology. 3D planning has influenced today's workflow, planning of complex surgery and contributed to useful further innovations and efficient healthcare.

Множинна ідіопатична апікальна зовнішня резорбція кореня: огляд даних літератури

Introduction. Domestic literature characterized with deficiency of publications regarding prevalence, diagnosis and treatment of multiple idiopathic external apical root resorption, on the other hand in the foreign literature, according to the data available for analysis, only one systematic review and a small number literature reviews dedicated to this topic were verified, while the predominant share of information presented in the form of clinical case reports. Objective. To systematize data regarding distribution and prevalence, clinical manifestations, and treatment approaches of multiple idiopathic external apical root resorption. Methodology/Methods. The primary identification of publications associated with the purpose of this study was carried out in the PubMed database (NCBI) (https://www.ncbi.nlm.nih.gov/pubmed/) using the following search descriptor: "multiple[All Fields] AND idiopathic[ All Fields] AND external[All Fields] AND apical[All Fields] AND ("root resorption"[MeSH Terms] OR ("root"[All Fields] AND "resorption"[All Fields]) OR "root resorption"[All Fields] Fields])". Results and Discussion. The most typical characteristics of multiple idiopathic external apical root resorption include: absence of clinical signs of periodontal tissues damage; the level of bone tissue in the area of affected teeth can be characterized by the normal values; absence of periradicular area inflammation signs; the possibility of pathology verification both in the area of vital and endodontically treated teeth; absence of local etiological factors; asymptomatic course, except for cases of severe forms of pathology; bilateral symmetrical pattern of development. Conclusions. Multiple idiopathic apical root resorption is a diagnosis of exclusion. The course of idiopathic external apical multiple resorption is usually asymptomatic, so the identification of the disease takes place during X-ray examinations. In the course of previous studies, sufficient evidences were not identified regarding the relationship between hidden pulpal lesions and the development of multiple idiopathic apical root resorption, so endodontic treatment is not recommended for clinical cases of the above mentioned disorder if pulpitis or periodontitis symptoms are absent. Data from individual publications indicate a genetic predisposition to the development of multiple idiopathic apical root resorption, based on the results of pathology verification among family members and among monozygotic twins.

Selective estrogen receptor modulators in post-menopausal osteoporosis

Osteoporosis (OP) is a chronic disease that occurs when the balance between the processes of bone formation and resorption is lost. OP is characterized by a decrease in bone quality and an increased risk of fractures. In post-menopausal women, as a result of decreased estrogen levels, there is bone loss. Hormone replacement therapy was initially used for the management of OP in post-menopausal women but was soon abandoned due to the occurrence of significant side effects. This shifted research toward the development of a class of drugs called selective estrogen receptor modulators (SERMs). These drugs always act through estrogen receptors (ERs), but as agonists or antagonists depending on the tissue under consideration. In particular, SERMs at the level of bone tissue behave as agonists of ERs but, as they do not result in the occurrence of estrogen side effects, they are widely used in the therapy of post-menopausal OP. This review provides a brief summary of the characteristics of SERMs employed in the treatment of post-menopausal OP.

Induction of protective interferon-β responses in murine osteoblasts following Staphylococcus aureus infection.

The refractory and recurrent nature of chronic staphylococcal osteomyelitis may be due, at least in part, to the ability of Staphylococcus aureus to invade and persist within bone-forming osteoblasts. However, osteoblasts are now recognized to respond to S. aureus infection and produce numerous immune mediators and bone regulatory factors that can shape the host response. Type I interferons (IFNs) are best known for their antiviral effects, but it is becoming apparent that they impact host susceptibility to a wide range of pathogens including S. aureus. Here, we have assessed the local expression of IFN-β by specific capture ELISA in an established in vivo mouse model of staphylococcal osteomyelitis. RNA Tag-Seq analysis, specific capture ELISAs, and/or immunoblot analyses, were then used to assess the expression of type I IFNs and select IFN stimulated genes (ISGs) in S. aureus infected primary murine osteoblasts. The effect of IFN-β on intracellular S. aureus burden was assessed in vitro following recombinant cytokine treatment by serial colony counts of liberated bacteria. We report the presence of markedly elevated IFN-β levels in infected bone tissue in a mouse model of staphylococcal osteomyelitis. RNA Tag-Seq analysis of S. aureus infected osteoblasts showed enrichment of genes associated with type I IFN signaling and ISGs, and elevated expression of mRNA encoding IFN-β and ISG products. IFN-β production was confirmed with the demonstration that S. aureus induces its rapid and robust release by osteoblasts in a dose-dependent manner. Furthermore, we showed increased protein expression of the ISG products IFIT1 and IFIT3 by infected osteoblasts and demonstrate that this occurs secondary to the release of IFN-β by these cells. Finally, we have determined that exposure of S. aureus-infected osteoblasts to IFN-β markedly reduces the number of viable bacteria harbored by these cells. Together, these findings indicate an ability of osteoblasts to respond to bacteria by producing IFN-β that can act in an autocrine and/or paracrine manner to elicit ISG expression and mitigate S. aureus infection.

Effectiveness of resisting torsional loads of various options for osteosynthesis of tibial fragments (according to the results of mathematical modeling)

Recently, there has been a trend towards high statistical indicators of the number of bone fractures of the lower limbs(47.3%), of which diaphyseal fractures of the lower leg bones make up 45‒56 %. Objective. Conduct a comparative analysisof the stress-strain state of leg models with a fracture of the tibia under the torsional loading combined with various optionsof osteosynthesis and depending on the patient's weight. Methods. A fracture was modeled in the middle third of the diaphysisof the tibia and three types of osteosynthesis — with the help of an external apparatus fixation (EAF), periosteal plate andintramedullary rod Bones were attached to the tibial plateau torque of 7 Nm and 12 Nm. Results. It was determined thatthe changes in stress levels in bone tissue depend linearly on the patient's weight. Under simulation conditions stabilizationof the fracture with the help of EAF and intramedullary stress rod in the fracture area were found significantly lowerthan the level of indicators of intact bone. In this same zone in the model with a bony plate, the value stress levels were lowerthan the intact model bone, but with an increase in the patient's weight to 120 kg, these indicators almost leveled off. The highest stress level was recorded in the distal part of the tibia in the model with intramedullary rod osteosynthesis, and inthe proximal one, the stresses that exceeded the parameters of the model with intact bone were determined under the conditions use of EAF. The largest in metal structures stress is detected in the periosteal plate. Conclusions. The highest stresses in the fracture zone (5.8‒9.9 MPa) and on the metal structure (360.0‒617.0 MPa) was recorded in a model with a bone plate. In the model with EAF in the zone of the fracture, the stresses were at the level of 0.1‒0.2 MPa, in the proximal part of the tibia — 6.3‒10.8 MPa, in the model with an intramedullary rod — 0.1‒0.2 MPa and 0.5‒0.9 MPa, respectively. In the distal partof the stress in the last model remained high — 11.7‒20.1 MPa.

High-fat diet-induced obesity augments the deleterious effects of estrogen deficiency on bone: Evidence from ovariectomized mice.

Several epidemiological studies have suggested that obesity complicated with insulin resistance and type 2 diabetes exerts deleterious effects on the skeleton. While obesity coexists with estrogen deficiency in postmenopausal women, their combined effects on the skeleton are poorly studied. Thus, we investigated the impact of high-fat diet (HFD) on bone and metabolism of ovariectomized (OVX) female mice (C57BL/6J). OVX or sham operated mice were fed either HFD (60%fat) or normal diet (10%fat) for 12 weeks. HFD-OVX group exhibited pronounced increase in body weight (~86% in HFD and ~122% in HFD-OVX, p < 0.0005) and impaired glucose tolerance. Bone microCT-scanning revealed a pronounced decrease in trabecular bone volume/total volume (BV/TV) (-15.6 ± 0.48% in HFD and -37.5 ± 0.235% in HFD-OVX, p < 0.005) and expansion of bone marrow adipose tissue (BMAT; +60.7 ± 9.9% in HFD vs. +79.5 ± 5.86% in HFD-OVX, p < 0.005). Mechanistically, HFD-OVX treatment led to upregulation of genes markers of senescence, bone resorption, adipogenesis, inflammation, downregulation of gene markers of bone formation and bone development. Similarly, HFD-OVX treatment resulted in significant changes in bone tissue levels of purine/pyrimidine and Glutamate metabolisms, known to play a regulatory role in bone metabolism. Obesity and estrogen deficiency exert combined deleterious effects on bone resulting in accelerated cellular senescence, expansion of BMAT and impaired bone formation leading to decreased bone mass. Our results suggest that obesity may increase bone fragility in postmenopausal women.

The evaluation of stress on bone level and tissue level short implants: A Finite Element Analysis (FEA) study

PurposeThis study aimed to evaluate the difference between the stress level and distribution around the BL and TL short implants, and their surrounding structures, using finite element analysis. MethodsTwo different study models were constructed: BL model and TL model. Two dental implant systems (ITI (Straumann, Waldenburg, Switzerland) and NTA Short) with a diameter of 4.1 mm and 4 mm and with a length of 6 mm were used in this study. In each model, implants were placed in the mandibular 1st molar region. The von Mises stress and maximum principal (tensile) and minimum principal (compressive) stresses were evaluated. ResultsThe highest stress values recorded in the BL implants (von Mises: 342.77 MPa), in the peri‑implant bone around the BL implants (maximum principal stress: 114.1 MPa), as a result of oblique loading, and overall stress values were found to be higher in the BL model. However, these measured values appeared to be low to cause a fracture, when considering the yield strengths of the materials and bone. ConclusionsThe stress values were higher in the BL model, but not high enough to cause failure. Short implants could be an effective method of treatment for patients unsuitable for advanced surgical techniques.

Comparison of levels of toxic trace elements in two most common spinal pathologies in three different tissues

Aim: The toxic trace element levels in serum, bone (lamina), and intervertebral disc tissues of patients with lumbar spinal stenosis and lumbar herniated nucleus pulposus (HNP) which are the two most common spinal pathologies were determined, and it was investigated whether they have a role in the pathophysiology of these pathologies. Materials and methods: Cadmium (Cd), aluminium (Al), arsenic (As), mercury (Hg), and lead (Pb) levels in serum, intervertebral disc, and bone (lamina) tissue of patients with HNP (=20) and 30 with lumbar spinal stenosis (LSS) (n=30) were determined by Inductively Coupled Plasma Mass Spectrometry technique. Results: LDH group Cd serum level was found to be significantly higher than LSS group Cd serum level (p=0.024). The Al disc level in the HNP group was found to be significantly higher than the Al disc level in the LSS group (p=0.038). While As serum level increased in LDH group, it was determined that As bone level increased very significantly (r= 0.699, p=0.001). In the LSS group, it was determined that the Hg disc level increased significantly as the Hg serum level increased (r=0.608, p&lt;0.01). On the other hand, as the Hg serum level increased in the LDH group, the Hg disc level also decreased significantly (r= -0.579, p&lt;0.01). Conclusion: The difference in toxic trace element levels seen in these pathologies has been discussed in terms of possible causes in light of current literature. The findings of our study support the hypothesis that toxic trace elements may be effective in lumbar disc degeneration.

Bone-Targeting Nanoparticles of a Dendritic (Aspartic acid)3-Functionalized PEG-PLGA Biopolymer Encapsulating Simvastatin for the Treatment of Osteoporosis in Rat Models.

Simvastatin (SIM) is a lipid-lowering drug that also promotes bone formation, but its high liver specificity may cause muscle damage, and the low solubility of lipophilic drugs limits the systemic administration of SIM, especially in osteoporosis (OP) studies. In this study, we utilized the bone-targeting moiety of dendritic oligopeptides consisting of three aspartic acid moieties (dAsp3) and amphiphilic polymers (poly(ethylene glycol)-block-poly(lactic-co-glycolic acid); PEG-PLGA) to create dAsp3-PEG-PLGA (APP) nanoparticles (NPs), which can carry SIM to treat OP. An in vivo imaging system showed that gold nanocluster (GNC)-PLGA/APP NPs had a significantly higher accumulation rate in representative bone tissues. In vivo experiments comparing low-dose SIM treatment (0.25 mg/kg per time, 2 times per week) showed that bone-targeting SIM/APP NPs could increase the bone formation effect compared with non-bone-targeting SIM/PP NPs in a local bone loss of hindlimb suspension (disuse) model, but did not demonstrate good bone formation in a postmenopausal (ovariectomized) model of systemic bone loss. The APP NPs could effectively target high mineral levels in bone tissue and were expected to reduce side effects in other organs affected by SIM. However, in vivo OP model testing showed that the same lower dose could not be used to treat different types of OP.

Biomechanical performance of Ti-PEEK dental implants in bone: An in-silico analysis

Stress-shielding is caused by a significant mismatch in stiffness between bone tissue and Ti alloy dental implants. Therefore, in this study, a Ti-PEEK composite implant was examined and compared with conventional titanium, to determine the behavior of the host bone. Twelve 3D finite element models were modeled with two conditions of marginal cortical bone (with and without marginal bone loss). Six implant designs were constructed. Implant (A) was made with a conventional design (dense titanium), implants (B), (C) and (D) are designed with Ti-PEEK composite (outer layer made of PEEK and inner structures made of Ti with hexagonal, cylindrical, and cross shapes for implants (B), (C) and (D), respectively), the implant (E) is designed with Ti at the upper half section and PEEK at the bottom half section, and the implant (F) is designed with PEEK at the upper half section and Ti at the bottom half section. An axial load of 200 N was applied to the buccal cusp and central fossa of the occlusal surface. The displacements, stress, and equivalent strain were analyzed at the level of bone tissue. The mechanostat of Frost was used to determine the behavior of the cancellous bone under these biomechanical conditions. Results showed that strains were greater in cancellous bone with marginal bone loss than in healthy bone (w/o MBL). When compared to implants (B)-(F), conventional implant (A) did not produce as much strain. Thus, results and analyses suggest that the Ti-PEEK implants outperform compared with the implant (A) in the case of no marginal bone loss. However, the implants (A) and (E) perform equally in terms of bone loss.

Use of reactive soft tissue for primary wound closure during immediate implant placement: a two-year retrospective study

Sockets with both hard and soft tissue defects present a challenge for immediate implant placement. A modified technique harnessing the reactive soft tissue in the extraction socket for primary closure has been reported to contribute to hard and soft tissue augmentation after immediate implantation. The aim of this study was to evaluate the effects of this novel technique on the hard and soft tissues of sockets with both buccal bone and soft tissue defects (group B) and to compare the outcomes with those obtained for sockets with intact soft tissue but buccal bone dehiscence (group A). Thirty-two implants placed in the posterior region were included: 17 in group A, 15 in group B. The implants were inserted immediately utilizing reactive soft tissue from the socket for primary closure in both groups. The changes in buccal bone dimensions after 6 months were generally comparable between the two groups. A keratinized mucosa reduction of 0.56 mm in group A and keratinized mucosa gain of 0.67 mm in group B were observed at 6 months (P = 0.009). The bone and soft tissue levels were well maintained in both groups after 2 years. This technique may be a potential treatment method for tissue augmentation during immediate implantation in posterior sockets, even when a buccal bony defect and mucogingival recession need to be repaired at the same time.

Molecular investigations of the prenucleation mechanism of bone-like apatite assisted by type I collagen nanofibrils: insights into intrafibrillar mineralization.

Bone is a typical inorganic-organic composite material with a multilevel hierarchical organization. In the lowest level of bone tissue, inorganic minerals, which are mainly composed of hydroxyapatite, are mineralized within the type I collagen fibril scaffold. Understanding the crystal prenucleation mechanism and growth of the inorganic phase is particularly important in the design and development of materials with biomimetic nanostructures. In this study, we built an all-atom human type I collagen fibrillar model with a 67 nm overlap/gap D-periodicity. Arginine residues were shown to serve as the dominant cross-linker to stabilize the fibril scaffold. Subsequently, the prenucleation mechanism of collagen intrafibrillar mineralization was investigated using a molecular dynamics approach. Considering the physiological pH of the human body (i.e., ∼7.4), HPO42- was initially used to simulate the protonation state of the phosphate ions. Due to the spatially constrained effects resulting from the overlap/gap structure of the collagen fibrils, calcium phosphate clusters formed mainly inside the hole zone but with different spatial distributions along the long axis direction; this indicated that the nucleation of calcium phosphate may be highly site-selective. Furthermore, the model containing both HPO42- and PO43- in the solution phase formed significantly larger clusters without any change in the nucleation sites. This phenomenon suggests that the existence of PO43- is beneficial for the mineralization process, and so the conversion of HPO42- to PO43- was considered a critical step during mineralization. Finally, we summarize the nucleation mechanism for collagen intrafibrillar mineralization, which could contribute to the fabrication of mineralized collagen biomimetic materials.

Aesthetic Outcomes of Early Occlusal Loaded SLA Dental Implants with Hydroxyl Ion Modified Surface—A 12 Months Prospective Study

Background: Many efforts have been made recently to arrange a newer, more hydrophilic and more osteoconductive implant surface. One of the possible options in this matter is modification with hydroxyl ion. Materials and Methods: Forty implants with the diameters 3.5 and 4.0 mm were inserted as a single missing tooth restoration protocol in the frontal aspect of the maxilla. All implants were loaded early in a 4 week period. Prior to and during the surgery, the following indices were considered: height of keratinized tissue, the thickness of soft tissue, and the initial level of bone tissue. After 12 months, the implant and the tissues in its direct vicinity were evaluated once more with the following indices: marginal bone loss (MBL), height of keratinized tissue (HKT), probing pocket depth (PPD), pink and white aesthetics scores (PES, WES), as well as pain sensations combined with the procedure (VAS). All results were related to the diameter of the implant and thickness of periodontal biotype. Results: High aesthetic outcomes were reported regardless of soft tissue thickness and implant diameter. The VAS score was higher for the 4.0 implant group, and the thickness of soft tissue had no influence on VAS. In case of implantation in thin or soft tissue, higher MBL levels were reported (0.26 mm), while in case of a thick phenotype, MBL was 0.06 mm. Conclusions: Hydrophilic surface implants can be used for a protocol of early functional occlusal loading. The initial thickness of soft tissue does not influence aesthetic outcomes and does not raise pain perception, although it may elevate crestal bone resorption.

In premenopausal women with idiopathic osteoporosis, lower bone formation rate is associated with higher body fat and higher IGF-1.

Premenopausal women with idiopathic osteoporosis (IOP) have marked deficits in bone microarchitecture but variable bone remodeling. We previously reported that those with low tissue-level bone formation rate (BFR) are less responsive to teriparatide and have higher serum IGF-1, a hormone anabolic for osteoblasts and other tissues. The IGF-1 data were unexpected because IGF-1 is low in other forms of low turnover osteoporosis-leading us to hypothesize that IGF-1 relationships are paradoxical in IOP. This study aimed to determine whether IOP womenwith low BFR have higher IGF-1 and paradoxical IGF-1 relationships in skeletal and non-skeletal tissues, and whether IGF-1 and the related measures predict teriparatide response. This research is an ancillary study to a24month clinical trial of teriparatide for IOP. Baseline assessments were related to trial outcomes: BMD, bone remodeling. Premenopausal women with IOP(n = 34); bone remodeling status wasdefined by baseline cancellous BFR/BS on bone biopsy. Serum IGF-1 parameters, compartmental adiposity (DXA, CT, MRI), serum hormones, and cardiovascular-risk-markers related to fat distribution. As seen in other populations, lower BFR was associated with higher body fat and poorer teriparatide response. However, in contrast to observations in other populations, low BFR, higher body fat, and poorer teriparatide response were all related to higher IGF-1: IGF-1 Z-score was inversely related to BFR at all bone surfaces (r = - 0.39 to - 0.46; p < 0.05), directly related to central fat (p = 0.05) and leptin (p = 0.03). IGF-1 inversely related to 24month hip BMD %change (r = - 0.46; p = 0.01). Paradoxical IGF-1 relationships suggest that abnormal or atypical regulation of bone and fat may contribute to osteoporosis mechanisms in premenopausal IOP.

Prosthetic complications of fixed dental prostheses supported by locking-taper implants: a retrospective study with a mean follow-up of 5\xa0years

BackgroundRestoration with locking-taper implants is a widely used methodology. However, conical connection systems such as locking-taper implant systems have rarely been examined. This study provides a retrospective investigation of locking-taper fixed restorations, mainly focusing on prosthetic complications.MethodsPatients undergo treatment with conical connected implants from 2008 to 2010 were examined. Preparation of the implant sites was performed according to the standard procedures for the Bicon system. Bone healing took over 6 months, and the prosthetic procedure was initiated thereafter. Integrated abutment crowns or gold porcelain crowns were used, and the prosthesis type was a single crown or a fixed dental prosthesis. Once the crown was in place, its occlusion was thoroughly checked and adjusted, and then the crown was glazed or finely polished. The Kaplan–Meier method was used to calculate the cumulative complication-free rates for 5 and 10 years. Additionally, a Cox regression model was used to identify the factors that independently influenced the results. Implant survival and marginal bone loss were also investigated.ResultsA total of 392 patients who underwent 541 implants and 434 locking taper implant-based restorations from 2008 to 2010 were examined. The overall 5-year cumulative complication-free rate was 83.34%. The most common prosthetic complication was veneer chipping, with a frequency of 67.53%. According to the Cox regression model, the complication-free rate of integrated abutment crowns was significantly higher than that of gold porcelain crowns, that of molar regions was significantly higher than that of premolar regions, and that of females was significantly higher than that of males. Only three implant failures happened, and the mean marginal bone loss values at 1- year, 5-years and 10- years were 0.25 mm (95% CI ± 0.12), 0.40 mm (95% CI ± 0.03) and 0.51 mm (95% CI ± 0.05), respectively.ConclusionVeneer chipping was the most common complication with locking-taper implant-supported fixed restorations. The incidence of complications for IACs is significantly higher than that for GPCs. Age, location, and prosthesis type are not determinants of prosthetic complications. Besides, the long-term clinical effect of locking-taper implant can meet the clinical needs. The bone tissue level around the implant can maintain long-term stability.

The Comparison of Trace Element Levels in Serum, Bone and Intervertebral Disc Tissues of Patients with Lumbar Spinal Stenosis and Lumbar Disc Herniation

The Comparison of Trace Element Levels in Serum, Bone and Intervertebral Disc Tissues of Patients with Lumbar Spinal Stenosis and Lumbar Disc Herniation

Peri-Implant Behavior of Tissue Level Dental Implants with a Convergent Neck.

Introduction: The aim of this retrospective study was to analyze the radiographic peri-implant bone loss of bone level implants and tissue level implants with a convergent neck in screw-retained single crowns and in screw-retained fixed partial prostheses, after two years of functional loading. Materials and methods: The sample was divided into two groups according to their type: Group I: supracrestal implants with convergent transmucosal neck; Group II: crestal implants. In each group we distinguish two subgroups according to the type of prosthetic restoration: single crowns and a three-piece fixed partial prosthesis on two implants. To quantify bone loss, parallelized periapical radiographs were analyzed at the time of implant placement and after two years of functional load. Results: A total of 120 implants were placed in 53 patients. After statistical analysis it was observed that for each type of implant bone loss was 0.97 ± 0.91 mm for bone level and 0.31 ± 0.48 mm for tissue level. No significant differences were found regarding the type of prosthesis and the location (maxilla or mandible) of the implants. Conclusions: Tissue level implants with a convergent transepithelial neck exhibit less peri-implant bone loss than bone level implants regardless of the type of prosthesis.