Early Loading Research Articles

Healing of Endosseous Implants Having Different Surface Characteristics in the Alveolar Bone: A Clinical Study.

Background Total treatment time in implant placement can be significantly reduced by placing immediate implants into the freshly extracted sockets. Also, immediate implant placement can act as a guide for proper and accurate implant placement. Additionally, in immediate implant placement, the resorption of bone associated with the healing of the extraction socket is also reduced. This clinical study aimed to clinically and radiographically assess the healing of endosseous implants having different surface characteristics in nongraftedand grafted bone. Methodology In 68 subjects, 198 implants were placed, including 102 oxidized (TiUnite, Göteborg, Sweden) and 96 turned surface implants (Nobel Biocare Mark III, Göteborg) were placed. Survival was considered with clinical stability and acceptable function with no discomfort and no radiographic or clinical signs of pathology/infection. Rest cases that showed no healing and implant no osseointegration were considered failures. Clinical and radiographic examination was done by two experts aftertwo years of loading based on bleeding on probing (BOP) mesially and distally, radiographic marginal bone levels, and probing depth (mesial and distal). Results Fiveimplantsfailed in total where four implants were with the turned surface (Nobel Biocare Mark III) and one was from the oxidized surface (TiUnite). The one oxidized implant was in a 62-year-old female and was placed in the region of mandibular premolar (44) of length 13 mm and was lost within five months of placement before functional loading. Mean probing depth had a nonsignificant difference between oxidized and turned surfaces with the mean values of 1.6 ± 1.2 and 1.5 ± 1.0 mm, respectively, with P= 0.5984; mean BOPin oxidized and turned surfaces was 0.3 ± 0.7 and 0.4 ± 0.6, respectively (P= 0.3727). Marginal bone levels, respectively, were 2.0 ± 0.8 and 1.8 ± 0.7 mm (P= 0.1231). In marginal bone levels related to implant loading, a nonsignificant difference was seen in early loading and one-stage loading with P-values of 0.06 and 0.09, respectively. However, in two-stage placement, significantly higher values were seen for oxidized surfaces (2.4 ± 0.8 mm) compared to turned surfaces (1.9 ± 0.8 mm), with P= 0.0004. Conclusions This study concludes that nonsignificantly higher survival rates are associated with oxidized surfaces compared to turned surfaces after two years of follow-up. Higher marginal bone levels were seen in oxidized surfaces for single implants and implants placed in two stages.

Immediate Loading of Dental Implants with Fixed Prosthodontic Constructions-Advantages and Methods

“Immediate loading of implants” implies loading of implants after extraction of a tooth. The goal of our study was to observe the loss of keratinized gums and bone tissue in the region surrounding the alveolar ridge after tooth extraction, and to compare it to the immediate loading of dental implants with the same indicator. Recently, immediate implant placement after the extraction of a tooth with early loading has become more common. The advantages of this procedure include fewer surgical interventions, reduction in overall treatment time, reduced soft and hard tissue loss, and psychological satisfaction for the patient. This study shows the advantages and methods for immediate implant placement with immediate provisional restorations.

Whole-body vibration ameliorates glial pathological changes in the hippocampus of hAPP transgenic mice, but does not affect plaque load

BackgroundAlzheimer’s disease (AD) is the core cause of dementia in elderly populations. One of the main hallmarks of AD is extracellular amyloid beta (Aβ) accumulation (APP-pathology) associated with glial-mediated neuroinflammation. Whole-Body Vibration (WBV) is a passive form of exercise, but its effects on AD pathology are still unknown.MethodsFive months old male J20 mice (n = 26) and their wild type (WT) littermates (n = 24) were used to investigate the effect of WBV on amyloid pathology and the healthy brain. Both J20 and WT mice underwent WBV on a vibration platform or pseudo vibration treatment. The vibration intervention consisted of 2 WBV sessions of 10 min per day, five days per week for five consecutive weeks. After five weeks of WBV, the balance beam test was used to assess motor performance. Brain tissue was collected to quantify Aβ deposition and immunomarkers of astrocytes and microglia.ResultsJ20 mice have a limited number of plaques at this relatively young age. Amyloid plaque load was not affected by WBV. Microglia activation based on IBA1-immunostaining was significantly increased in the J20 animals compared to the WT littermates, whereas CD68 expression was not significantly altered. WBV treatment was effective to ameliorate microglia activation based on morphology in both J20 and WT animals in the Dentate Gyrus, but not so in the other subregions. Furthermore, GFAP expression based on coverage was reduced in J20 pseudo-treated mice compared to the WT littermates and it was significantly reserved in the J20 WBV vs. pseudo-treated animals. Further, only for the WT animals a tendency of improved motor performance was observed in the WBV group compared to the pseudo vibration group.ConclusionIn accordance with the literature, we detected an early plaque load, reduced GFAP expression and increased microglia activity in J20 mice at the age of ~ 6 months. Our findings indicate that WBV has beneficial effects on the early progression of brain pathology. WBV restored, above all, the morphology of GFAP positive astrocytes to the WT level that could be considered the non-pathological and hence “healthy” level. Next experiments need to be performed to determine whether WBV is also affective in J20 mice of older age or other AD mouse models.

Marginal Bone Level Measurements of Unsplinted Implants Used for Mandibular Overdentures: A Six-Month Randomized Prospective Clinical Study Comparing Early and Delayed Loading Protocols.

Background and purpose Implant-supported mandibular overdentures are a good alternative for patients having poor retention of mandibular conventional dentures. The aim of this prospective study was to evaluate and compare the results between early loading and delayed loading of mandibular overdentures on two unsplinted implants. Materials and methods A total of 14 completely edentulous male patients in the age group of 50-60 years were selected for the study. Two 3.5×13 mm implants were placed in the mandibular interforaminal region. The patients were divided into two groups: (i) the test group in which the overdenture was connected after one week of surgery, and (ii) the control group, in which the overdenture was connected three months after surgery. Marginal bone levels were evaluated at baseline (during loading), three months, and six months post loading. Unpaired 't' test was used for the comparison of intergroup measurements. Results No implants were lost. Marginal bone resorptions showed no statistically significant differences between the two groups over six months period after loading. Conclusion The results of this prospective clinical study suggested that there was no significant difference in the clinical and radiographic state of patients treated with implant-supported mandibular overdentures loaded either one week or three months after implant surgery.

Assesment of Rospatent open data quality within the context of integration with national current research information systems

Current Research Information Systems (CRIS) are to aggregate data on organizational research projects and their funding, on employers’ publications and intellectual property subject matters. The scientometric analysis is based on CRIS data to assess research output and innovative potential of organizations, and to make management solutions. The early loading of quality and reliable information is the most important task for CRIS. The Rospatent open data that allow for automated processing based on free (free of charge) licensing makes the potential source for data on intellectual property subject matters (patent and government registration certificates) for national CRIS. The studies evidence that despite publishing OD in machine-readable formats, their practical application is impeded by incorrect, incomplete and uncoordinated entries. Therefore, before loading. Rospatent OD have to be assessed for quality and to be improved, if possible. As for today, Rospatent OD quality is assessed by several criteria: accessibility, metadata completeness, feedback. However, at the content level, the open data have not been assessed. The purpose of the article is to evaluate the internal quality of Rospatent OD sets including information on inventions, utility models, industrial designs, computer programs, databases, circuit layouts, within the context of OD integration in CRIS systems. The quality is assessed in several characteristics: completeness, accuracy, consistency, expedience, and relevancy. The study has revealed incomplete, inaccurate and uncoordinated entries.

Acoustic emission for identification of the dominant stress component in polymer composites at early loads

Carbon Fiber Reinforced Polymer (CFRP) composites are broadly used in engineering applications. Their inherent anisotropy due to different fiber orientations can be considered an advantage since the strength of the component can be designated in preferential loading directions. However, this anisotropy leads to multiaxial stress conditions, complicating their damage sequence and mechanical response. Identification of these multiaxial conditions at early loading stages is of paramount importance to predict the upcoming structural response of the material. Acoustic Emission (AE) is applied in this study to CFRP laminates with different stacking sequences, in which different multiaxial conditions are generated. Laminates consisting of 30o plies are characterized by dominant shear stresses, whereas in laminates with 60o layers transverse normal stresses govern the stress state. Through quasi-static and incremental loading, it is shown that certain AE features can be used to identify the dominant stress component rather than just the occurring damage mode even at early loads, before severe fracture influences the mechanical capacity. This is of great importance in cases that detrimental shear stresses are generated, leading to delaminations and mechanical deterioration. AE can be used in this direction to predict the upcoming damage and to take necessary measures to avoid final failure.

Современная система интрамедуллярной фиксации вертельных переломов бедренной кости: Обзор литературы

The problem of treating patients with trochanteric fractures of the femur is relevant, due to the high incidence of fractures among the elderly due to increased life expectancy along with osteoporosis and the difficulty in choosing implants for osteosynthesis. Implants for intramedullary osteosynthesis are the method of choice for fixing such fractures. The purpose of this review: to study the advantages of implants for intramedullary osteosynthesis of trochanteric femoral fractures.The article provides an analysis of literature sources indexed in the Scopus, PubMed, Google Scholar, Lilacs and Cuiden databases, devoted to the study of the method of intramedullary osteosynthesis of trochanteric femoral fractures. The results made it possible to establish that modern intramedullary implants provide stable fixation of fragments even in osteoporosis, minimal blood loss during surgery, shortening of surgery time, early postoperative load and are safe and effective.The modern system of intramedullary fracture fixation is recognized as a highly effective method, especially in unstable trochanteric and subtrochanteric fractures of the femur, provides high antirotational stability of structures, overcomes the “Z” effect, medial migration of the cervical screw and minimally invasive intervention. Further research allows us to note the promising directions of the surgical method of treating patients with trochanteric fractures of the femur. Optimization of implants for intramedullary osteosynthesis of trochanteric fractures is a promising direction in traumatology and orthopedics.Key words: trochanteric fracture, femur, osteosynthesis, intramedullary osteosynthesis, metal structures, osteoporosis.

Efficacy of Three Different Photobiomodulation Therapies on Primary and Secondary Implant Stability in D3 and D4 Bone Type- A Research Protocol for Randomised Controlled Trial

Introduction: Osseointegration is considered one of the most important deciding factors to check for implant stability, which decides successful outcome of the implant. Photobiomodulation has been used to improve the implant stability by enhancing osseointegration. Photobiomodulation (PBM) or Low-level Laser Therapy (LLLT) causes an enhanced effect in the bone implant contact. Need for the Study: There are no definitive therapies/protocol of LLLT in cases of bone density of D3 and D4. Also There are no studies in literature which compares the different laser settings so that a standardised setting can be established. Therefore, there is need to generate evidence whether reducing the number of appointments and reducing the amount of energy given in D3 and D4(compromised) bone can help achieve early loading in patients. Aim: To evaluate and compare the effect of three different photobiomodulation therapies on primary and secondary implant stability in D3 and D4 bone type in comparison to control group to achieve early loading. Materials and Methods: This randomized controlled, double blinded study allocated 108 patients having D3 or D4 bone according to Misch classification into six groups. Three different PBM therapy which is either Therapy A, B or C(placebo) will be used. The implant stability will be measured by Ostell meter in Implant Stability Quotients (ISQ) scale, immediately after surgery, after 3 weeks, after 12 weeks and after 6 months of surgery. The bone density will be measured before surgery and 3 months after surgery. Expected Outcome: At the end of the study, an evidence will be generated whether reducing the number of appointments and reducing the amount of energy given in D3 and D4(compromised) bone can help achieve early loading in patients. Patients treated using PBM therapy either protocol A or protocol B may show enhanced implant stability.

Smile in a Day: A Case Report on Compressive Implants

The replacement of missing teeth has become a transition from dentures to dental implants in the present era. Implant placement in anterior regions has the most aesthetic challenges in implant dentistry as tooth loss leads to bone resorption and collapse of gingival architecture, which causes aesthetic compromise and inadequate bone for implant placement. Immediate implant placement and loading have become a popular treatment modality and they are being widely used to reduce the treatment time which is a major disadvantage with conventional implants. Immediate implant placement into fresh extraction socket maintains gingival aesthetics and increases the comfort of the patient. The present case report highlights the placement of two compressive implants into fresh extraction sockets and immediate loading within 72 h or less than that. Immediate placement and early loading of the dental implant provide advantages such as fewer surgical procedures, shorter treatment time and improved aesthetic and psychological confidence.

Multimodal NDT monitoring of TRC sandwich under bending and early detection of interlaminar debonding

Textile Reinforced Cementitious (TRC) sandwich composites provide a load-bearing, noncorrosive, lightweight, and durable alternative for steel-reinforced sandwich elements, and/or traditional steel-reinforced concrete. However, the composite nature of the material and slender nature of the facings render the fracture behavior complex. Insufficient interlaminar bond can cause premature debonding, substantially reducing the loadbearing capacity of the composite. Non-Destructive Testing (NDT) techniques seem the obvious choice to monitor the damage progression of the material without affecting, nor compromising the behavior of the composite, and predict their service life. In this study, TRC sandwich composites, subjected to quasistatic four-point bending, are monitored with three NDTs. Digital Image Correlation (DIC) allows to measure the surface strains and displacements. MMW Spectrometry, used for the first time in bending damage monitoring, allowed to detect damage such as cracking, or debonding, while Acoustic Emission (AE) allowed to localize and characterize internal cracking. In order to simulate premature debonding, the bond between the tensile TRC facing and the insulation, in the central zone, where the bending moment is maximum, was artificially destroyed. Results show that a weak interlaminar bond reduced the ultimate load of the composite by more than 50%. Additionally, DIC, AE and MMW Spectrometry proved useful to monitor and characterize damage. Multimodal data gathered from the multimodal NDTs showed to be complementary. DIC allowed to interpret AE and MMW Spectrometry data from a surface viewpoint, while AE parameters permit predictions at low load conditions, and detect internal cracking. For instance, the AE behavior at early load stage (less than 15% of the maximum load) of the TRC sandwich with destroyed bond showed significant differences than for the reference TRC sandwich. Specifically, it showed higher RA values, and lower AF than the reference TRC sandwich, suggesting more shear related early activity for, promoted by the damaged bond. Results were corroborated with DIC, while MMW Spectrometry seemed to follow closely the level of damage of TRC sandwich composites under quasi-static four-point bending. EWGAE 35, Ljubljana, Slovenia, 13th – 16th Sep. www.ewg

Application of Early Loading on Surface Implants with Nanostructured Hydroxyapatite Coating

The objective of this work was to describe the variation in the stability of nanostructured HA coatied implants installed in the upper premolar area by means of resonance frequency analysis (RFA, measured in ISQ) during the first 4 weeks, in partially edentulous patients. The study design is quantitative, observational, descriptive, longitudinal and prospective. The implants used were the UNITITE line of S.I.N Implant System® of 3.5 mm x 11.5 mm, which have HAnano® surface. These implants have a surface treatment with a nanostructured hydroxyapatite coating, which increases hydrophilicity and would accelerate the process of new bone formation and remodeling after installation. The surgeries were carried out by students of the Oral Maxillofacial Implantology department, at Universidad Mayor, Santiago. A descriptive analysis was performed on a sample of 8 implants, resulting in a variation of 1 to 2 ISQ points during the four weeks studied. The results suggest that as the stability of the implants keeps constant, it would be possible to carry out early loading at 4 weeks in the implants studied, however, a greater number of samples, comparative studies and longer-term studies are required to generate more robust conclusions on this subject.

Seismic behavior of mortise–tenon joints reinforced with lightweight steel components

Mortise–tenon joints (MTJs) exhibit good energy dissipation and have been widely used in wooden houses since ancient times. Based on the failure mode of wood joints, reinforcement methods for MTJs, such as steel strip plate (SSP), hollow rectangular steel plate (HRSP), diagonal bracing steel plate (DBSP), grooved steel plate with triangular stiffener (GSPTS), and angle steel with double triangular stiffener (ASDTS) reinforcement, have been proposed. Low-cyclic loading tests were conducted on 11 wood joints to investigate their seismic performances. The failure characteristics, hysteretic curve, skeleton curve, stiffness degradation, energy dissipation, tenon-pulling value, and strain were compared and analyzed. The experimental results indicated that the failure modes of joints with or without reinforcements were beam pull-out, self-tapping screw pull-out, and shear failure. The joint with ASDTS reinforcement exhibited the best seismic performance, followed by HRSP, DBSP, and SSP reinforcement. The seismic performance of joints with GSPTS reinforcement was better in the early loading stage but became poor in the later stage owing to the deformation of the GSPTS reinforcement, causing damage to the timber. A detailed numerical simulation was performed, and the results indicated that with the improvement in the moduli of elasticity parallel and perpendicular to the grain, and friction coefficient, the stiffness and peak bearing capacity of the wood joints increased. Increasing the yield strength of the self-tapping screw and steel plate had a slight effect on the initial stiffness, but it increased the peak bearing capacity of the wood joints.

Acute kidney injury and early fluid load in a retrospective cohort of neonatal sepsis.

Sepsis and acute kidney injury (AKI) are associated with mortality in the newborn intensive care unit (NICU). There is a paucity of studies that describe AKI and fluid overload in neonatal sepsis and their association with mortality. Retrospective study of neonates with culture positive sepsis admitted to the NICU between June 2020 and June 2021 was conducted. Primary outcome was in-hospital mortality according to AKI as defined by the neonatal modified Kidney Diseases Improving Outcomes criteria. Secondary outcomes were early fluid overload and vasopressor use. Thirty-three percent of neonates had AKI with sepsis, and 57% of cases were severe AKI. AKI was associated with mortality after adjusting for variables that were different between survivors and non-survivors (aOR 5.7 [95% CI 1.1-36], p = 0.04). Early fluid overload occurred in 27% of neonates who were at higher risk of having AKI with sepsis (OR 7.4 [95% CI 1.6-26.0], p = 0.01) and higher risk of mortality (aOR 17.8 [95% CI 2-7545], p = 0.02). AKI and early fluid overload are associated with mortality in sepsis in our retrospective cohort. Mitigating AKI and early fluid overload in sepsis might be a fruitful strategy in reducing mortality with sepsis. A higher resolution version of the Graphical abstract is available as Supplementary information.

Influence of multi-scale fiber on residual compressive properties of a novel rubberized concrete subjected to elevated temperatures

Green and environment-friendly rubberized concrete has attracted extensive attention from scholars worldwide. However, the incorporation of crumb rubber can weaken the mechanical properties of concrete, particularly when it is subjected to elevated temperatures. To improve the residual compressive performance of rubberized concrete, a novel multi-scale fiber reinforced rubberized concrete (MSFRRC) is developed by adding calcium carbonate whiskers, polyvinyl alcohol (PVA) fibers, and steel fibers. In this study, 10%, 20%, and 30% of the sands are substituted by the same volume of crumb rubber with sizes between 0.4 mm and 0.8 mm. The impacts of the crumb rubber content and multi-scale fiber on the residual Young's modulus, axial compressive strength, peak strain, stress-strain curve, and compressive toughness of MSFRRC after being heated up to various temperature levels (25 °C, 200 °C, 400 °C, 600 °C, and 800 °C) are discussed. Also, the failure mode combined with the acoustic emission technology and the thermal effect on the microstructure of rubberized concrete specimens, are investigated. Results reveal that incorporating multi-scale fiber can effectively restrain the development of cracks and explosive spalling under high temperatures. Besides, it can cover the strength loss caused by crumb rubber and impose a positive effect on resisting thermal damage. The compressive strength of MSFRRC can be enhanced by about 5.4%–19% with the incorporation of different fibers. The results show that specimens without fibers suddenly fail once the peak stress is reached and exhibit brittle fracture. However, the brittleness can be improved by adding multi-scale fibers. It can be observed that, after exposure to 800 °C, the damage of MSFRRC can develop at the early loading stage and develop in the whole loading process, showing a relatively ductile fracture. Meanwhile, the pore structure can be refined by adding CaCO3 whiskers and the addition of multi-scale fibers can slightly increase the porosity and cannot restrain the heating-induced pore coarsening. Furthermore, the empirical formulas to predict the residual stress-strain relation of MSFRRC under uniaxial compression are proposed by considering crumb rubber, multi-scale fibers, and high temperature.

Transosseous Repair With Nice Knot Augmentation Versus Knotless Suture Anchor Repair With Suture Tape for Quadriceps Tendon Rupture: A Cadaveric Study.

Quadriceps tendon rupture is typically repaired using either transosseous tunnels or suture anchors. Recent literature has suggested that suture anchor repair is biomechanically superior to the use of transosseous tunnels. Augmentation of the transosseous technique with Nice knots may result in improved biomechanical properties as compared with a suture anchor construct. To compare biomechanical properties of a novel transosseous quadriceps tendon repair technique with Nice knot augmentation to those of knotless suture anchor repair, an artificial quadriceps tendon rupture was created in 10 matched pairs of cadaveric knees (n=20). Each cadaver was subjected to biomechanical testing to calculate the average ultimate load to failure, repair site gapping after early and late cyclic loading, and stiffness. Transosseous repair augmented with Nice knots as compared with knotless suture anchor repair had greater load to failure (mean±SD, 1489.5±297.6 N vs 717.7±191.4 N, P<.001), decreased gapping after early and late cyclic loading (cycles 1-20: mean±SD, 0.59±0.4 mm vs 2.1±1.2 mm, P=.008; cycles 21-250: mean±SD, 1.2±0.7 mm vs 3.9±1.7 mm, P=.002), and greater construct stiffness (mean±SD, 80.7±15.7 N/mm vs 44.4±13.4 N/mm, P=.001). The transosseous quadriceps tendon repair technique with Nice knot augmentation is biomechanically better than knotless suture anchor repair with regard to ultimate load to failure, gap formation after cyclic loading, and construct stiffness in cadaveric specimens. [Orthopedics. 2023;46(3):135-140.].

Mechanical Complications After Intramedullary Fixation of Extracapsular Hip Fractures.

Extracapsular hip fractures occur frequently in the elderly as a result of low-energy trauma. Achieving stable fixation in osteoporotic bone to allow early weight bearing is a key objective in the treatment of these injuries. Many of the intraoperative decisions facing surgeons are directed by first determining fracture stability. Unstable fracture patterns should be fixated with intramedullary nails, aiming to control motion around the implant and at the fracture site. Torsion control devices provide additional stability and control, although their exact indications are not precisely defined. Complications that arise as a result of the early loading can be avoided with a good surgical reduction, meticulous technique, and proper implant selection. Mechanical complications include cutout, inordinate proximal femoral shortening, delayed union, early implant fracture, nail toggle, and cut through/medial migration.

Load carrying behavior of concrete reinforced with bundled BFRP bars by using DIC

Recently, basalt fiber-reinforced polymer (BFRP) has gained attention in the construction industry because of its worldwide availability and eco-friendly nature. Different from conventional steel bars, BFRP bar do not corrode being an ideal reinforcing material in structures surrounding magnetic fields and marine environments, given its chemical stability. This study investigated the load carrying behavior of concrete beams reinforced with conventional deformed steel bars and seven-bundled BFRP bars through four-point flexural test. For each case, two beams were prepared; one beam was designed with a low reinforcement ratio and another with a high reinforcement ratio in order to obtain a load carrying capacity of around 330–368 kN and 483–519 kN, respectively. Deflection, crack width evolution, and strain behavior of each beam were comparatively analyzed using a digital image correlation (DIC) based technique. The DIC analysis results showed that the neutral axis of bundled BFRP reinforced cases move to the upper end in an early loading stage, with larger cracks width, and the deflection is larger in BFRP cases than in those of steel-reinforced beams with the respective reinforcement ratio. However, the four-point flexural test results revealed that bundled BFRP bars can be used as an alternative to conventional steel bars. The load carrying capacities were obtained similarly to designed values, around 364 and 551 kN for low and high reinforcement ratio cases, respectively.

Immediate Loading of Dental Implants with Fixed Prosthodontic Constructions Advantages and Methods

“Immediate loading of implants” implies loading of implants after extraction of a tooth. The goal of our study was to observe the loss of keratinized gums and bone tissue in the region surrounding the alveolar ridge after tooth extraction, and to compare it to the immediate loading of dental implants with the same indicator. Recently, immediate implant placement after the extraction of a tooth with early loading has become more common. The advantages of this procedure include fewer surgical interventions, reduction in overall treatment time, reduced soft and hard tissue loss, and psychological satisfaction for the patient. This study shows the advantages and methods for immediate implant placement with immediate provisional restorations.

Bi-Linear Bond-Slip Modelling for 1-D Tension Stiffening Behavior of a RC Element

Cracking is an inherent characteristic of a reinforced-concrete (RC) element subjected to tension or bending. The crack width growth with loading depends on the rebar-concrete bond behavior. RC bridges are designed under strict requirements to ensure their proper long lifetime performance. Limiting the crack widths improves the performance and safety of bridges that are exposed to harsh climatic and environmental effects and enhances bridge service life-cycle expectancy. This paper presents an extended one-dimensional formulation for analyzing RC elements subjected to tensile loads and solves the one-dimensional tension stiffening problem. The extended bond-slip model analyses the entire range of loading, following cracks growth up to their maximum allowed width, employing a bi-linear bond-slip relationship. The analytical solution refers to the early loading stage where the first bond-slip segment governs the entire element and a closed form solution is obtained, followed by the higher loading stage where two different bond-slip relationships govern two complementary segments of the element. Analytical expressions for the stresses, strains, and displacements in concrete, steel, and interface are developed. Cracking is followed until rebar yielding. Validation of the model with available test results shows good agreement that is superior to the commonly used linear bond-slip model.

Comparison of marginal bone loss in implant supported over dentures in early loading

Aim: The purpose of the present research was to evaluate the marginal bone loss in implant supported over-dentures in case of early loading on denture. Methodology: 36 edentulous participants (mean age 68 years, SD 9.2) were randomly assigned into three treatment groups (n¼12). A single implant was placed in the mandibular midline of participants to support an overdenture using a 6-week loading protocol. The control group received Southern regular implants and standard ball attachments. One group received Southern 8-mm-wide implants and large ball attachments. Another group received Neoss regular implants and Locator attachments. SPSS was used to determine between groups differences in marginal bone loss, implant stability, implant, and prosthodontic success (P&lt;0.05). Results: Implant success after 1 year was 75% for Southern regular implant (control) group; and 100% for the Southern wide and Neoss regular implant groups (P¼0.038). Prosthodontic success was comparable between the groups but the maintenance (41 events overall, mean 1.2) was greater for the Locator and the standard ball attachments. Conclusion: Mandibular single-implant overdentures are a successful treatment option for older edentulous adults with early loading protocol using implants of different diameters and with different attachment systems.