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Surgical treatment has been established as the standard method for the treatment of intertrochanteric fractures in the elderly. The design of internal fixation devices has become the key to improving surgical outcomes and reducing postoperative complications. Centered on optimizing biomechanical performance and minimally invasive implantation, coupled with continuous material improvements, the design philosophy of internal fixation devices has also been constantly evolving. There have been several milestone advancements, such as the transition from eccentric fixation to central fixation, the adoption of sliding compression fixation, the replacement of traditional screws with spiral blades, and the shift from single to double (combination) nails. However, the incidence of internal fixation-related complications has remained at a relatively high level of 5% to 10%, without significant breakthroughs. Increasing evidence suggests that in-depth analysis of the anatomy, physiological mechanisms, and mechanical transmission characteristics of the proximal femur can help elucidate the root causes of internal fixation failures. Based on this, the proximal femoral bionic nail (PFBN) has emerged as a new design concept. By fully mimicking the anatomical, mechanical, and biological characteristics of the proximal femur, the PFBN can regulate the local mechanical environment, providing a revolutionary solution and a new approach for the treatment of proximal femoral fractures. This innovative design also has the potential to drive the paradigm shift in the treatment strategies of other fractures.
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Objective: To evaluate the clinical effect of socket-shield technique for 5 years after immediate implantation and immediate restoration in aesthetic area. Methods: The retrospective study was conducted between July, 2013 and July, 2020. A total of 29 patients, with 34 implants, who received immediate implantation and immediate restoration with socket-shield technique in the esthetic zone in Department of Fourth Clinical Division, Peking University School and Hospital of Stomatology were included in this study. The implants survival rate, complications and the pink esthetic score (PES) were evaluated (60.2±26.7) months (13-101 months) after operation. The digital models before treatment and at the final follow-up were obtained, to measure the changes of soft tissue. The labial alveolar bone recession was measured by cone-beam CT. Results: All 34 implants survived during follow-up. The PES was (12.80±1.05), there was no significant difference in PES scores between dental positions (F=1.77, P=0.150). The gingival margin recession was (0.12±0.09) mm, and labial contour change at 2 mm apical to the gingival zenith was (0.45±0.17) mm. The labial alveolar bone recession was (0.14±0.46) mm. Conclusions: Immediate implant with socket-shield technique could maintain the gingival margin and labial alveolar bone, and preserve the soft tissue contour well to achieve good esthetic outcome.
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The objective of this study was to perform a comparative evaluation of the radiographic outcomes of lateral sinus floor elevation with and without bone window repositioning (BLSFE and LSFE, respectively) when applied concomitantly with implant placement. A randomized controlled clinical trial was conducted between February 1, 2016 and May 1, 2017 including 26 individuals with at least one missing tooth. Participants were randomized 1:1 to undergo BLSFE (10 participants, 16 implants) or LSFE (13 participants, 19 implants). Bovine-derived xenograft was used in both groups and the implants were inserted concomitantly. In the BLSFE group, the antrostomy was covered with a repositioned bone window and then with a concentrated growth factors (CGF) membrane. In the LSFE group, the antrostomy was covered with a CGF membrane. Panoramic radiographs were taken before surgery (T0), immediately postoperative (T1), and at 12 months postoperative (6 months after loading) (T2). Marginal bone loss (MBL), apical bone gain, augmented alveolar bone height, and intra-sinus bone augmentation were evaluated on panoramic radiographs at T2. A linear regression analysis with generalized estimating equation models was performed. The implant survival rate was 100% at 1 year after implant surgery. The residual alveolar bone height at T0 was comparable in the BLSFE and LSFE groups (3.58 ± 1.49 mm vs 4.12 ± 1.61, P = 0.32), as was the alveolar bone height at T1 (13.61 ± 1.82 mm vs 12.38 ± 1.82 mm, P = 0.06). At T2, significantly higher alveolar bone height, intra-sinus bone augmentation, and apical bone gain, and lower distal MBL were observed in the BLSFE group when compared to the LSFE group, with adjusting for covariates (ß = 2.44, 95% CI 1.42-3.46, P < 0.0001; ß = 2.38, 95% CI 1.35-3.41, P < 0.0001; ß = 2.33, 95% CI 1.23-3.42, P < 0.0001; and ß = -0.43, 95% CI -0.83 to -0.02, P = 0.038, respectively). No significant difference was observed for mesial MBL or apical bone resorption at T2. Lateral sinus floor elevation with bone window repositioning may result in higher bone augmentation after 1 year than the traditional approach. Further research is needed to elucidate the effect of lateral sinus floor elevation with bone window repositioning.
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Implantes Dentales , Elevación del Piso del Seno Maxilar , Senos Transversos , Humanos , Animales , Bovinos , Implantación Dental Endoósea/métodos , Elevación del Piso del Seno Maxilar/métodos , Senos Transversos/cirugía , Trasplante Óseo/métodos , Seno Maxilar/diagnóstico por imagen , Seno Maxilar/cirugíaRESUMEN
The ^{13}C(α,n)^{16}O reaction is the main neutron source for the slow-neutron-capture process in asymptotic giant branch stars and for the intermediate process. Direct measurements at astrophysical energies in above-ground laboratories are hindered by the extremely small cross sections and vast cosmic-ray-induced background. We performed the first consistent direct measurement in the range of E_{c.m.}=0.24 to 1.9 MeV using the accelerators at the China Jinping Underground Laboratory and Sichuan University. Our measurement covers almost the entire intermediate process Gamow window in which the large uncertainty of the previous experiments has been reduced from 60% down to 15%, eliminates the large systematic uncertainty in the extrapolation arising from the inconsistency of existing datasets, and provides a more reliable reaction rate for the studies of the slow-neutron-capture and intermediate processes along with the first direct determination of the alpha strength for the near-threshold state.
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Objective: Statistical significance plays an important role in the interpretation of clinical trial results. However, on the basis of obtaining statistical significance, the assessment of clinical significance is often neglected. This study attempted to propose a simple and unambiguous new classification method for study results, focusing on studies with statistical positive findings to evaluate whether the results have clinical significance. Methods: Our study subjects were the clinical studies in 2019 ACC and ESC annual meetings. Meta-epidemiology methods were used to extract the characteristic variable from each study. The primary evaluation indicators included target effect-size and observed effect-size. Based on the difference between the two indicators, the studies that had statistical significance were subdivided to identify studies with possible insufficient clinical significance; Furthermore, the theoretical threshold based on power analysis was proposed, which was used as the basis for the interpretation of study results. Results: There were 12 clinical studies included in the final analysis. All of them were published on top journals. Those studies had relative high quality on both study design and reporting. The correlation coefficient between the observed and target effect-size was 0.892. Among the 7 studies with statistical significance, two of them were classified as insufficient clinical significance. The counts was 1 (1/3) and 1 (1/4) for the studies reported in ACC and ESC respectively. Conclusions: The achievement of clinical significance is critical even in the study with positive results. This paper proposes a new classification standard that combines clinical significance with statistical significance and further suggests a method to evaluate the reliability of clinical study results in order to assist researchers in identifying potential risks caused by insufficient clinical significance, and provide some reference and help for the reasonable interpretation of clinical study results.
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Reproducibilidad de los Resultados , Estudios Epidemiológicos , HumanosRESUMEN
A plasma radiation measurement system for a wide spectral range, based on compact Absolute eXtreme UltraViolet (AXUV) silicon photodiodes, has been implemented on the newly constructed ENN XuanLong-50 (EXL-50) spherical tokamak. The system consists of two 16-channel AXUV16ELG arrays and one AXUV63HS1 single-cell detector mounted on ceramic sockets. The two arrays, facing toward the EXL-50 slim central post from two locations inside a top and a side ConFlat 400 port, have 32 view chords covering the interested plasma region in a poloidal cross section at toroidal 330°. The single-cell detector, seated on a retractable feedthrough, could be arranged flexibly with the help of an ultra-high vacuum compatible gate valve. The design details together with considerations on the EXL-50 specific engineering realities and physics requirements are described. Preliminary results from the EXL-50 2020 experimental campaign are presented.
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A toroidal soft x-ray array system for spectrum and intensity measurements on the EXL-50 spherical tokamak is described. Silicon drift detectors and digital multichannel analyzers are adopted for all 21 channels of the array, and an average energy resolution of 147 eV at 5.89 keV has been achieved at count rates over 500 kcps. In total, 20 channels of the array are symmetrically observed in both co- and counter-current directions on the EXL-50 mid-plane with a spatial resolution of around 10 cm, and the remaining one serves as a background reference channel. Tungsten emissions from tungsten coating of the limiters on the central post are observed. The influence of hard x rays on measured soft x-ray spectra and system operation is discussed.
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A tangential hard x-ray (HXR) diagnostic on the newly constructed ENN XuanLong-50 (EXL-50) spherical tokamak for fast electron emission studies is presented. The HXR detection system consists of a symmetrical CdZnTe semiconductor detector array with a spectral sensitivity range of 20-300 keV. 25 channels have been designed on the 270° horizontal vacuum port with 12 sight lines to observe the forward emission, 12 sight lines to observe the backward emission of fast electrons, and 1 for viewing the central. Currently, ten channels have been in operation in the EXL-50 experiments. The systems are designed to measure the x-ray spectra for the estimation of fast electron temperature and electron velocity distribution in the EXL-50 experiment, which will be useful for understanding the dynamics of fast electrons generated by electron cyclotron resonance heating, for plasma instability and transport studies and for the analysis of plasma heating efficiency.
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The neutral particles generated by charge exchange reactions can play an important role in erosion of first wall materials in fusion devices. In order to measure the flux and energy of neutral particles to the first wall, a low-energy neutral particle analyzer (LENPA) based on the time-of-flight method has been developed and successfully applied on the Experimental Advanced Superconducting Tokamak (EAST)' to measure the neutrals with an energy of 20-3000 eV. The LENPA works in the counting mode, and the signal of photons is used as the reference for the flight time of neutrals. The energy spectrum of low-energy neutral particles on EAST has been obtained for the first time. The new diagnostics can help in understanding the neutral particle generation and deposition on the first wall materials in tokamaks under different plasma conditions.
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OBJECTIVE: Long noncoding RNA (lncRNA) plays a vital role in the progression of various cancers. However, the potential mechanisms of NR2F1-AS1 in the tumorigenesis of neuroblastoma (NB) have not been determined. PATIENTS AND METHODS: The expression levels of NR2F1-AS1, miR-493 and TRIM2 were detected by RT-qPCR. The downstream target genes of NR2F1-AS1 or miR-493 were predicted by bioinformatics analysis (http://starbase.sysu.edu.cn/), which was further indicated by Luciferase reporter and RNA immunoprecipitation (RIP) assays. CCK-8, transwell, and TUNEL assays were performed to determine the viability, migration, invasion and apoptosis of NB cells. RESULTS: NR2F1-AS1 was highly expressed and miR-493 was lowly expressed in NB tissues and cell lines. The high expression of NR2F1-AS1 was associated with poor prognosis in NB. NR2F1-AS1 knockdown inhibited proliferation, migration, and invasion, and accelerated apoptosis of NB cells. MiR-493 was a downstream target of NR2F1-AS1, and the silencing of miR-493 reversed NR2F1-AS1 knockdown-attenuated progression of NB. Moreover, TRIM2 was demonstrated to be directly targeted by miR-493, and the upregulation of TRIM2 could abolish the inhibitory effect of miR-493 overexpression on the progression of NB. Finally, it was found that NR2F1-AS1 regulated TRIM2 expression by sponging miR-493. CONCLUSIONS: The present study demonstrated that NR2F1-AS1 promoted the progression of NB through the miR-493/TRIM2 axis. This finding may provide new insight into the treatment of NB.
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MicroARNs/metabolismo , Neuroblastoma/metabolismo , ARN Largo no Codificante/metabolismo , Proteínas de Motivos Tripartitos/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Células Cultivadas , Humanos , MicroARNs/genética , Neuroblastoma/patología , ARN Largo no Codificante/genética , Proteínas de Motivos Tripartitos/genética , Ubiquitina-Proteína Ligasas/genéticaRESUMEN
Objective: To evaluate the efficacy and long-term outcome of the bilaminar cortical wall building grafting technique for reconstruction of vertical and horizontal alveolar ridge defects in the esthetic zone. Methods: The retrospective study was conducted between January, 2007 and December, 2015. The sample was composed of 24 patients who received bilaminar cortical wall building augmentation in the esthetic zone in Department of Fourth Clinical Division, Peking University School of Stomatology. The 24 patients (11 female and 13 male) had age of (37.8±13.4) years (20-54 years). A bone block harvested from the lateral aspect of the mandibular ramus was bisected into two cortical laminae, which were then used to reconstruct the buccal and palatal walls of an alveolar ridge defect. The inter-laminar space was filled with particulate autogenous bone and the whole graft was covered with anorganic bone graft and collagen membrane. Bone width and vertical measurements were measured at the time of surgery and reentry surgery. Integration of the graft, implant survival rates and complications were recorded. Results: Overall, 24 patients with 35 sites who were included were followed for (7.1±1.9) years. Graft integration (24/24) and implant survival rates (35/35) were determined as 100%. The average horizontal and vertical bone gain was (6.47±2.46) and (5.01±1.12) mm with resorption rates of 9.0% and 10.9%, respectively. One patient showed soft-tissue dehiscence with peri-implant mucositis were observed 9 years after surgery. More than 1.5 mm of buccal bone plate were observed using cone beam computed tomography. Conclusions: This technique was effective and reliable for three-dimensional reconstruction of severely atrophic alveolar ridges in anterior maxillae. Autogenous graft combined with coverage by allogeneic bone graft and collagen membrane provided successful augmentation with low bone resorption.
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Aumento de la Cresta Alveolar , Maxilar , Proceso Alveolar , Trasplante Óseo , Implantación Dental Endoósea , Estética Dental , Femenino , Humanos , Masculino , Maxilar/cirugía , Estudios RetrospectivosRESUMEN
Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "The expression of overexpressed PTEN enhanced IR-induced apoptosis of myocardial cells, by Y.-B. Zhu, N. Ding, H.-L. Yi, Z.-Q. Li, published in Eur Rev Med Pharmacol Sci 2019; 23 (10): 4406-4413-DOI: 10.26355/eurrev_201905_17948-PMID: 31173315" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/17948.
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The optimization of thermoelectric materials involves the decoupling of the transport of electrons and phonons. In this work, an increased Mg1-Mg2 distance, together with the carrier conduction network protection, has been shown as an effective strategy to increase the weighted mobility (U = µm ∗3/2) and hence thermoelectric power factor of Mg3+δ Sb2-y Bi y family near room temperature. Mg3+δ Sb0.5Bi1.5 has a high carrier mobility of 247 cm2 V-1 s-1 and a record power factor of 3470 µW m-1 K-2 at room temperature. Considering both efficiency and power density, Mg3+δ Sb1.0Bi1.0 with a high average ZT of 1.13 and an average power factor of 3184 µW m-1 K-2 in the temperature range of 50-250°C would be a strong candidate to replace the conventional n-type thermoelectric material Bi2Te2.7Se0.3. The protection of the transport channel through Mg sublattice means alloying on Sb sublattice has little effect on electron while it significantly reduces phonon thermal conductivity, providing us an approach to decouple electron and phonon transport for better thermoelectric materials.
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OBJECTIVE: Current studies reporting the association between VDR polymorphisms and susceptibility to hypertension are controversial. This meta-analysis aims to obtain a precise correlation estimate between VDR polymorphisms and susceptibility to hypertension. MATERIALS AND METHODS: Relevant studies were searched in PubMed, Web of Science, CNRI, Wanfang, and VIP using the keywords as "Vitamin D receptor, hypertension", "Vitamin D receptor polymorphism, hypertension", and "VDR, hypertension". ORs and corresponding 95%CI of eligible studies were calculated using RevMan5.3 and STATA12.0. RESULTS: Seven independent studies reporting the association between VDR gene polymorphisms and hypertension were enrolled. VDR rs1544410 (BsmI) was associated with susceptibility to hypertension. The frequency of VDR BsmI AA genotype decreased in hypertension patients compared with healthy controls. The population carrying VDR BsmI AA genotype had lower susceptibility to hypertension relative to those carrying GA or GG genotype (OR = 0.69, 95% CI = 0.54-0.89, p = 0.005). Meanwhile, the frequency of A allele was higher in the case group than that of control group (OR = 0.83, 95% CI = 0.69-0.99, p = 0.04). No significant correlation was found between VDR FokI or VDR ApaI with susceptibility to hypertension. CONCLUSIONS: VDR BsmI gene polymorphism is closely related to the susceptibility to hypertension.
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Hipertensión/genética , Polimorfismo de Nucleótido Simple , Receptores de Calcitriol/genética , Femenino , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Humanos , MasculinoRESUMEN
A passive and noninvasive diagnostic system based on high-frequency B-dot probes (HFBs) has been designed and developed for the measurement and identification of ion cyclotron emission (ICE) in the Experimental Advanced Superconducting Tokamak (EAST). Details of the hardware components of this system including HFBs, direct current blockers, radio frequency splitters, filters, and power detectors as well as data acquisition systems are presented. A spectrum analyzer is used in addition to the ordinary speed acquisition card for data registration and analysis. The reliability of a HFB based diagnostic system has been well validated during the 2018 spring experiments on the EAST. ICE signals corresponding to fundamental cyclotron frequency of hydrogen ions and harmonics of deuterium ions were observed in experiments where deuterium plasmas were heated with deuterium neutral beams. The field dependence of ICE has been verified by recent experiments with three different background magnetic fields. The observed ratio of the ICE frequency is consistent with the ratio of the magnetic field intensity within measurement errors of a few percent.
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OBJECTIVE: Myocardial cell apoptosis is an important pathologic basis of ischemia-reperfusion injury (I/R). PI3K/Akt signaling pathway involves in cell growth, survival, and apoptosis regulation, thus playing an important role in the protection of I/R injury. PTEN is a negative regulatory factor of PI3K/Akt signaling pathway. This study established rat I/R injury model after AMI and myocardial cell I/R injury model to explore the regulatory role of PTEN-PI3K/Akt signaling pathway in myocardial I/R injury in vivo and in vitro. MATERIALS AND METHODS: Rat myocardial I/R injury model was established. PTEN and p-Akt expressions in myocardial tissue were compared. H9C2 cells were incubated in I/R condition for 12 h, followed by reoxygenation for 12 h. H9C2 cells were divided into three groups, including I/R+pSicoR-Blank, I/R+pSicoR-PTEN, and I/R+pSicoR-PTEN+VO-Ohpic. PTEN, p-Akt, Bcl-2, and Bax expressions were detected. Cell apoptosis was measured by flow cytometry. RESULTS: PTEN expression significantly increased, while p-Akt level markedly declined in myocardial tissue in I/R group compared with Sham group. Temporary PTEN downregulation and p-Akt elevation appeared at 2 h after I/R. I/R treatment markedly enhanced PTEN and Bax expressions, increased cell apoptosis, and reduced p-Akt and Bcl-2 levels. PTEN overexpression significantly enhanced Bax expression and cell apoptosis, while declined p-Akt and Bcl-2 in H9C2 after I/R. PTEN inhibited by VO-Ohpic markedly downregulated p-Akt and Bcl-2 expressions, whereas reduced Bax level and cell apoptosis. CONCLUSIONS: The overexpression of PTEN aggravated myocardial cell apoptosis after I/R. The blockage of PTEN enhanced PI3K/Akt signaling pathway and attenuated cell apoptosis induced by I/R.
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The Tianzhu white yak, a domestic yak indigenous to the Qilian Mountains, migrated inland from the Qinghai-Tibet Plateau. Specific ecological and long-term artificial selection influenced the evolution of its pure white coat and physiological characteristics. Therefore, it is not only a natural population that represents a genomic selective region of environmental adaptability but is also an animal model for studying the pigmentation of the yak coat. A total of 24 261 829 variants, including 22 445 252 SNPs, were obtained from 29 yaks by genome-wide re-sequencing. According to the results of a selective sweep analysis of Tianzhu white yak in comparison to Tibetan yaks, nine candidate genes under selection in Tianzhu white yak were identified by combining π, Tajima's D, πA/πB and FST statistics, with threshold standards of 5%. These genes include PDCD1, NUP210, ABCG8, NEU4, LOC102287650, D2HGDH, COL4A1, RTP5 and HDAC11. Five of the nine genes were classified into 12 molecular signaling pathways, and most of these signaling pathways are involved in environmental information processing, organismal systems and metabolism. A majority of these genes has not been implicated in previous studies of yak coat color and high-altitude animals. Our findings are helpful not only for explaining the molecular mechanism of yak coat pigmentation but also for exploring the genetic changes in Tianzhu white yak due to environmental adaptation.
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Bovinos/genética , Pigmentación , Animales , Bovinos/fisiología , China , Estudio de Asociación del Genoma Completo , Polimorfismo de Nucleótido SimpleRESUMEN
Vasculogenic mimicry (VM) refers to the fluid-conducting channels formed by aggressive tumor cells rather than endothelial cells (EC) with elevated expression of genes associated with vascularization. VM has been considered as one of the reasons that glioblastoma becomes resistant to anti-VEGF therapy. However, the molecular basis underlying VM formation remains unclear. Here we report that the insulin-like growth factor-binding protein 2 (IGFBP2) acts as a potent factor to enhance VM formation in glioma. Evidence showed that elevated IGFBP2 expression was positively related with VM formation in patients with glioma. Enforced expression of IGFBP2 increased network formation of glioma cells in vitro by activating CD144 and MMP2 (Matrix Metalloproteinase 2). U251 cells with stable knockdown of IGFBP2 led to decreased VM formation and tumor progression in orthotopic mouse model. Mechanistically, IGFBP2 interacts with integrin α5 and ß1 subunits and augments CD144 expression in a FAK/ERK pathway-dependent manner. Luciferase reporter and ChIP assay suggested that IGFBP2 activated the transcription factor SP1, which could bind to CD144 promoter. Thus, IGFBP2 acts as a stimulator of VM formation in glioma cells via enhancing CD144 and MMP2 expression.
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Neoplasias Encefálicas , Glioma , Receptores de Hialuranos/genética , Proteína 2 de Unión a Factor de Crecimiento Similar a la Insulina/fisiología , Metaloproteinasa 2 de la Matriz/genética , Neovascularización Patológica/genética , Animales , Neoplasias Encefálicas/irrigación sanguínea , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Movimiento Celular/genética , Regulación Neoplásica de la Expresión Génica , Glioma/irrigación sanguínea , Glioma/genética , Glioma/patología , Humanos , Receptores de Hialuranos/metabolismo , Proteína 2 de Unión a Factor de Crecimiento Similar a la Insulina/genética , Masculino , Metaloproteinasa 2 de la Matriz/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Ratones Transgénicos , Neovascularización Patológica/patología , Transducción de Señal/genéticaRESUMEN
Objective: To analyze the incidence and possible risk factors of 19 fractured implants out of 8 468 implants in 3 184 cases. Methods: During the 22-year clinical practice, clinical records of 18 patients with 19 fractured implants in 3 184 cases with 8 468 implants were analyzed to determine the following factors: location of the fractured implants, prosthodontics option, date of implant fracture, dimensions of fractured implants, complications prior to implant fracture and parafunctional habit. An evaluation of fractured implants was performed to identify possible factors that may predispose an implant to a higher risk of fracture. Results: Overall, the average duration of service of the implants was (7.0±4.5) years. Implant fracture occurred in 7 Camlog implants, 7 Nobel replace implants, 3 Ankylos implants and 2 Brånemark implants. No Thommen implant fractures were recorded. Amongst the 19 fractured implants, 8 occurred at the thinnest wall portion of the implant neck, 8 at the end of screw and 3 at the self-tapping thread region. All fractures were observed after functional loading. Furthermore, 9/19 (47.4%) of fractures occurred in the maxilla, indicating similar incidence rates in both arches (P=0.065). Most of fractures (16/19) occurred in the molar region and 18/19 in single implant-supported restorations. Totally 17 cases had received metal occlusal restorations. In 6 cases (35.5%), previous bone destruction apically extending to the level of implant fracture was documented before any clinical signs of fracture. Three fractured implants were removed and simultaneously re-implanted with larger-diameter implants, while the rest of the cases were left to heal, followed by a second-stage surgery. Conclusions: Within the limitation of this analysis, the study demonstrated that appropriate implant-abutment connection design, implant diameter, prosthetic strategy and bone resorption are crucial to the long-term performance of implants. There is no significant difference of fractures rates in both archs.