Cementation Technique Research Articles

Strength improvement of rock fractures and aggregates cemented with bio-slurry

Microbially induced carbonate precipitation (MICP) is a new environmentally friendly technique for grouting rock fractures and aggregates. However, this method can achieve only a limited degree of strength increase and low treatment efficiency. To address these limitations, an improved treatment method was designed and tested using bio-slurry (i.e., bacterial suspension with fine calcite particles), and the treatment effectiveness and strength of cemented rock fractures and aggregates were enhanced. The experimental results show that the rock specimens with fractures grouted using bio-slurry exhibited significantly higher shear strength values than those treated using the conventional MICP method, owing to a nearly six times higher filling ratio. The uniaxial compressive strength of the rock aggregates cemented using bio-slurry was two times higher than that treated using the conventional method, owing to the formation of more calcite crystals near the contact points between adjacent particles. The proposed bio-slurry method was demonstrated as an effective technique for cementation of rock fractures and aggregates with a higher efficiency than the traditional method.

Does the Risk of Death Within 48 Hours of Hip Hemiarthroplasty Differ Between Patients Treated with Cemented and Cementless Implants? A Meta-analysis of Large, National Registries.

Although current recommendations suggest that hip hemiarthroplasties performed for femoral neck fractures be implanted with bone cement, it is known to cause cardiorespiratory and hemodynamic reactions that in some patients can be fatal. Older patients may be at particular risk of this complication, but because of its relative infrequency, large studies-perhaps even larger than can be achieved in the context of single-country national registries-are needed to get reasonably precise estimates as to its frequency. Pooling results from national registries reporting on death within 48 hours of cement exposure in this setting may therefore be helpful. In a systematic review of studies based on large national registries, we asked: Does the risk of death within 48 hours of hip hemiarthroplasty differ between patients treated with cemented and cementless implants? MEDLINE and Embase data sources were searched for cohort studies on patients with hip fractures treated with cement or cementless hip hemiprostheses based on results from national registries that tracked perioperative deaths within 48 hours of surgery, from 2010 or later (to include only studies that used contemporary cement techniques). We excluded registry research on elective THAs for other indications (such as degenerative joint disease), mixed populations (registries that combined patients having arthroplasty for fracture and for other diagnoses like osteoarthritis, such that we could not separate them), and overlapping data from the same registers (to avoid double and triple publications of similar data). Five studies met our inclusion criteria. The cohorts ranged from about 11,000 to about 25,000 patients. About 31% of the patients were in the cementless group. Two studies reported the age ranges of participating patients, and three studies communicated mean ages (which were 82 years for both sexes). Twice as many females as males were present in both the cemented and cementless group. When reported, more than 50% in both groups were in the American Society of Anesthesiologists physical status classification 3 or 4. Study quality was deemed good according to the Newcastle-Ottawa Scale. Publication bias was assessed using a funnel plot and the Egger test, and study heterogeneity was evaluated using the I2 heterogeneity statistic and Cochran Q heterogeneity test. There was some heterogeneity between the studies, with a Cochran Q statistics of 8.13 (degrees of freedom = 4; p = 0.08) and an I2 statistic of 50.8%. There was evidence for a small amount of publication bias (Egger test; p = 0.02). The pooled risk ratio (RR) from a random-effects model is presented with 95% confidence intervals. The primary endpoint was the occurrence of any fatalities within 48 hours of hip fracture treatment with cementless compared with cemented prostheses. We performed a sensitivity analysis to assess the needed association of a potential unmeasured or uncontrolled confounding, and we made an estimate of the amount of unmeasured confounding that would need to be present in order to change the direction of the result. We summarized this using a parameter known as the "E-value." Based on that sensitivity analysis, we found it unlikely that an unmeasured hypothetical confounder could explain the significant association between cemented and cementless implants and risk of death within 48 hours of hip hemiarthroplasty. Compared with the cementless group, mortality was increased in the cemented group (RR 1.63 [95% CI 1.31 to 2.02]; p < 0.001). The number needed to harm from the pooled data was 1 of 183 operated patients; that is, for every 183 patients treated with cemented implants, one death would be expected. Bone cement is associated with a higher risk of fatalities within 48 hours of surgery compared with cementless prostheses. However, numerous prior studies have found a higher risk of serious complications resulting in additional surgical procedures associated with cementless devices in this population; those complications, as well, may result in death. Based on our study alone, we cannot recommend cementless implants in this setting. Large, national registries should evaluate fixation choice in older patients with hip fractures, and those studies should consider both early death and the potential for later harms. Level III, therapeutic study.

Restricted kinematic alignment may be associated with increased risk of aseptic loosening for posterior-stabilized TKA: a case-control study.

The purpose of the study was to compare clinical and radiological results between kinematic alignment (KA) and mechanical alignment (MA) with a posterior-stabilized (PS) total knee arthroplasty (TKA) with a post-cam mechanism at a minimum follow-up of 3years. The authors hypothesized a higher risk of aseptic loosening when performing KA using PS TKA. A retrospective monocentric single surgeon case control study was performed comparing 100 matched patients who had TKA performed using a MA philosophy to 50 patients receiving TKA with a KA technique between January 2016 and October 2017. All patients had the same knee prosthesis (GMK primary posterior-stabilized, Medacta®, Switzerland). Patient specific cutting blocks were used in both groups and a restricted KA (rKA) was aimed in the KA group. A hybrid cementation technique was performed. The new Knee Society Score (KSS) and radiological assessment were collected preoperatively and at the final follow-up. Comparisons between groups were done with the T test or Fisher exact test. Global survival curves were estimated with Kaplan-Meier model. Significance was set at p < 0.05. Mean follow-up was 42.9months ± 3.6 (range 37.6-46.7) and 53.3months ± 4.1 (range 45.5-59.8) for rKA and MA groups. Postoperatively, no significant differences were found for clinical scores between both groups. Radiological assessment found similar postoperative Hip-Knee-Ankle angle for rKA and MA groups (178° versus 179° respectively, NS). At last follow-up, a significant higher survivorship was found for the MA group compared to the rKA group (97 versus 84%; p < 0.001) for aseptic loosening revision as the endpoint. An increased risk of tibial implant loosening was found with rKA compared to MA using a posterior-stabilized TKA with a post-cam system at short-term follow-up. Caution should be taken when choosing the TKA design while performing rKA. Retrospective case-control study, Level IV.

Prospective clinical evaluation of chairside-fabricated zirconia-reinforced lithium silicate ceramic partial crowns\u20145-year results

ObjectivesA university-based randomized clinical study evaluated the 5-year performance of chairside-fabricated zirconia-reinforced lithium silicate (ZLS)-ceramic partial crowns.Material and methodsForty-five patients were restored with 61 chairside-fabricated ZLS-restorations (Cerec SW 4.2, Dentsply Sirona, Germany; Vita Suprinity, Vita Zahnfabrik, Germany). Deviating from the manufacturers’ recommendations, restorations with reduced minimum material thicknesses (MMT) were fabricated: group 1, MMT = 0.5–0.74 mm (n = 31); group 2, MMT = 0.75–1.0 mm (n = 30). For luting, a self-adhesive cement (SAC) or a total-etch technique with a composite cement (TEC) was applied. Statistical evaluation was performed by time-to-event analysis (Kaplan–Meier). Possible covariates of the survival (SVR) and success rates (SCR), evaluated in a Cox regression model, were MMT, restoration position (premolar/molar), and cementation technique (SAC vs. TEC).ResultsForty patients (54 restorations, premolars, n = 23; molars, n = 31) participated in the 5-year follow-up. Five losses due to ceramic fractures occurred in group 1 (n = 28) (SVR: 83.0% [95% confidence interval (CI): 0.71–0.96]). Group 2 (n = 26) showed no losses (SVR: 100%). The success rate for partial crowns placed on premolars was 100% and 69% (95% CI: 0.54–0.84) for molar restorations. Recementation was required in 4 restorations with SAC (SCR: 86% [95% CI: 0.73–0.99]; SCR-DC: 100%). Restorations in group 2 showed a significantly reduced risk of material fracture hazard ratio (HR) = 0.09, p = 0.0292) compared with the restorations in group 1. Molar partial crowns showed an increased risk for a clinical intervention (HR = 5.26, p = 0.0222) compared to premolar restorations.ConclusionsMaterial thickness and position of the restoration are risk factors influencing the survival and success rate of ZLS-ceramic partial crowns.Clinical relevanceObservation of an MMT of at least 0.75–1.0 mm for ZLS-ceramics is essential to avoid material-related fractures.Clinical trial registration: German Clinical Trails Register (trial number: DRKS00005611)

Novel Cemented Technique for Trochanteric Fixation and Reconstruction of the Abductor Mechanism in Proximal and Total Femoral Arthroplasty: An Observational Study.

BackgroundLittle evidence exists regarding the clinical outcomes of cemented trochanteric fixation for abductor mechanism reconstruction in proximal or total femoral replacements. Clinical outcomes were assessed for a novel cemented technique for trochanteric fixation in femoral megaprostheses.MethodsA descriptive series of 13 patients who underwent proximal or total femoral arthroplasty from 2016 to 2019 were reviewed. Radiographic trochanteric displacement >1 cm defined construct failure. A Kaplan-Meier survival analysis was performed to determine survival rates for these cemented constructs. Demographic information was obtained to better characterize the patient population in whom this technique was used.ResultsEleven patients were included (age = 63.6 years; 45.4% females; body mass index = 31.7). Mean time to final radiographic follow-up was 73.8 weeks. Three of 11 (27.2%) patients had construct failure. Overall, survival at 1 year was 81.8%. At 2 years, survival of cemented constructs was 65.5%. More construct failures occurred in patients who sustained a postoperative dislocation than in those who did not (P = .05).ConclusionsThis novel cemented trochanteric fixation technique for reconstruction of the abductor mechanism in femoral megaprostheses had 81.8% survival at 1 year postoperatively. While longitudinal comparative studies with larger samples are needed, the cemented technique may provide a viable alternative to traditional cementless methods of trochanteric fixation. Increased construct failure rates after postoperative dislocation highlight the importance of robust abductor reconstruction in these implants.

Improving the cementation of the tibial component in knee arthroplasty : a study of four techniques in the cadaver.

AimsThe main objective of this study is to analyze the penetration of bone cement in four different full cementation techniques of the tibial tray.MethodsIn order to determine the best tibial tray cementation technique, we applied cement to 40 cryopreserved donor tibiae by four different techniques: 1) double-layer cementation of the tibial component and tibial bone with bone restrictor; 2) metallic cementation of the tibial component without bone restrictor; 3) bone cementation of the tibia with bone restrictor; and 4) superficial bone cementation of the tibia and metallic keel cementation of the tibial component without bone restrictor. We performed CT exams of all 40 subjects, and measured cement layer thickness at both levels of the resected surface of the epiphysis and the endomedular metaphyseal level.ResultsAt the epiphyseal level, Technique 2 gave the greatest depth compared to the other investigated techniques. At the endomedular metaphyseal level, Technique 1 showed greater cement penetration than the other techniques.ConclusionThe best metaphyseal cementation technique of the tibial component is bone cementation with cement restrictor. Additionally, if full tibial component cementation is to be done, the cement volume used should be about 40 g of cement, and not the usual 20 g.Cite this article: Bone Joint Res 2021;10(8):467–473.

Cemented femoral stem fixation through the anterior approach has fewer early complications than cementless fixation.

To achieve the functional benefits of the direct anterior (DA) approach and the fixation benefits of cemented replacement, this study combined the two techniques posing the following questions: does the limited access of the DA approach adversely affect the cement technique?; and does such a cementing technique reduce the incidence of cementless complications? A consecutive series of 341 patients (360 hips) receiving the DA approach between 2016 and 2018 were reviewed. There were 203 cementless stems and 157 cemented stems. Mean age was 75 years (70 to 86) in the cementless group and 76 years (52 to 94) in the cemented group, with 239 (70%) females in the whole series. Femoral complications were compared between the two groups. Mean follow-up was 1.5 years (0.1 to 4.4) for patients in the cementless group and 1.3 years (0.0 to 3.9) for patients in the cemented group. The cementless group had a higher rate of femoral complications (8 vs 0; p = 0.011). There were two loose stems and six fractures, all requiring revision. Fractures occurred a mean 14.5 days (2 to 31) postoperatively and loosening at 189 days and 422 days postoperatively. Femoral cementing can be done using the DA approach safely and reduces the number of complications compared with a contemporary cementless series. A higher rate of early fractures and loosening occurred with cementless stems. This was not observed in our cemented stem cohort and cementing was safely accomplished through the DA approach. The modern femoral cementing process with the DA approach does not add to surgical complexity or time, has fewer early complications, and is a safer option for older patients compared to cementless femoral arthroplasties. Cite this article: Bone Joint J2021;103-B(7 Supple B):33-37.

Minimum ten-year outcome of a triple-tapered femoral stem implanted with line-to-line cementing technique

BackgroundA triple-tapered polished femoral stem was implanted with line-to-line cementing technique. The purpose of this study was to determine the survivorship, loosening rate, stem subsidence, radiologic changes and clinical outcomes in the minimum 10-year follow-up.MethodsThis was a retrospective study done in three institutes. Finally, 118 hips in 97 patients could be followed-up at the mean follow-up period of 126.3 months. The survivorship, radiological and clinical outcomes were investigated.ResultsRadiologically, 107 hips (90.7%) were categorized to Barrack cementing grade A, and 108 stems (91.5%) were inserted in neutral position. All hips were not loose and were not revised due to any reason. Survival with revision for any reason as the endpoint was 100% after 10 years. At the last follow-up, the mean subsidence was 0.43 mm, and the subsidence was less than 1 mm in 110 hips (93.2%).JOA hip score improved from 42.7 ± 8.9 points preoperatively to 92.8 ± 6.8 points at the last follow-up. No patient complained thigh pain.ConclusionsLine-to-line cementing technique with use of a triple-tapered polished stem was effective to achieve good cementation quality and centralization of the stem. The subsidence was small, and the minimum 10-year results were excellent without any failures related to the stem.Trial registrationRetrospectively registered.

Cement use in total knee arthroplasty: 40 versus 80 grams

BackgroundStudies of cement use in total knee arthroplasty (TKA) have historically addressed mechanical properties and application strategies. Recently, cement technique has been studied as a means to reduce cost. We transitioned from opening two bags (80 grams) of cement to one bag (40 grams) of cement for primary TKA to improve cost efficacy. This study investigates the radiographic outcome and cost of TKAs performed with 40 versus 80 grams of cement. MethodsTKAs from January 2017 to January 2019 were evaluated. Cement mantle and implant alignment were assessed per the Modern Knee Society Radiographic Evaluation System at four months by three blinded reviewers. Data was analyzed according to quantity of cement used. Cement mantle quality at 16 implant zones was compared. Cost was evaluated. Results163 patients (age 66.8 yrs. +/− 8.9, 51.5% female) underwent TKA with 80 grams of cement, while 142 patients (age 67.1 yrs. +/− 9.3, 56.3% female) underwent TKA utilizing 40 grams of cement. There was no significant difference in cement mantle quality. The most common zone of cement deficiency was the femoral posterior flange (9% in 40 gram group versus 4% in 80 gram group, p value = 0.08). There was no difference in implant size. Cost saving was calculated at $7,810 for the 40 gram group. ConclusionThere was no difference in radiographic cement mantle appearance between primary knees performed with 40 or 80 grams of cement. Cement usage represents a target for cost saving and opportunity to increase the value of primary TKA. Based on the current incidence of TKA in the United States, cost savings could exceed 33 million dollars annually.

Cementless unicompartmental knee arthroplasty results in higher pain levels compared to the cemented technique: a prospective register study

PurposeIn recent years, the preferred fixation method for unicompartmental knee arthroplasty (UKA) has changed from cemented to cementless. The aim of this study was to compare patient-reported outcome measures (PROMs) from the cemented versus cementless techniques two- and twelve-months post-operation.MethodsFrom 2015 to 2019, 187 cemented and 261 cementless UKAs were included based on an institutional registry. The Oxford Unicompartmental Knee System™ (Zimmer Biomet, Bridgend, United Kingdom) was used for all patients. Three experienced surgeons performed all procedures. Data were collected pre- and peroperatively, and at two- and twelve-months postoperatively. PROMs included pain (evaluated on a numeric rating scale [NRS] during activity and at rest), and knee function (evaluated with the disease-specific short form of the Knee injury and Osteoarthritis Outcome Score [KOOS-PS]). Patients also rated postoperative joint function (better, unchanged, uncertain or worse) and were asked, “based on your experience to date, would you go through the surgery again?”. Duration of surgery was noted and revisions during the first post-operative year were evaluated.ResultsThe cemented group reported significantly lower activity-related pain at both two- and twelve-month follow-up. This was also the case for pain at rest at twelve-month follow-up, and KOOS-PS at two-month follow-up. Duration of surgery (adjusted for surgeon differences) was eight minutes less on average with the cementless technique. Eleven prosthetic joint infections (PJIs) were found following the cementless fixation technique compared to three using the cemented implant.ConclusionUKA cases with cemented implants had lower pain scores during activity two and twelve months after surgery compared with those who had cementless implants. Differences in favor of the cemented group were also found for pain at rest one year after surgery and for KOOS-PS two months after. Surgery was significantly shorter in duration in the cementless group, but a relatively high number of PJIs were found in that same group.Level of evidenceLevel II.

Hot corrosion behavior of a Si Y co-deposition coating on a Ti2AlNb based alloy in NaCl-Na2SO4 mixture

A Si Y co-deposition coating was prepared on a Ti 2 AlNb based alloy by pack cementation technique. Hot corrosion behavior of this coating covered by a salt mixture composed of NaCl-Na 2 SO 4 at 1023 K was investigated. The results showed that application of the coating remarkably enhanced the hot corrosion resistance of the alloy, but the hot corrosion induced by the salt mixture affected the coating more seriously than mere oxidation in air. During the hot corrosion, the coating formed protective amorphous Na 2 Si 2 O 5 and effectively prevented ingress of corrosive media into the alloy. However, occurrence of self-sustaining sulfurization/oxidation and chlorination/oxidation reactions should be responsible for the accelerated degradation of the coating. Moreover, escape of gaseous corrosion products created holes in the scale. • Hot corrosion behavior of a Si Y co-deposition coating on Ti 2 AlNb alloy was studied. • The coating enhanced the hot corrosion resistance of the alloy in NaCl-Na 2 SO 4 . • The coating formed protective amorphous Na 2 Si 2 O 5 during the hot corrosion. • The coating effectively prevented ingress of corrosive media into the alloy. • The salts accelerated degradation of the coating and created holes in the scale.

Risk factors for a radiolucent line around the acetabular component with an interface bioactive bone cement technique after primary cemented total hip arthroplasty

AimsThe main aims were to identify risk factors predictive of a radiolucent line (RLL) around the acetabular component with an interface bioactive bone cement (IBBC) technique in the first year after THA, and evaluate whether these risk factors influence the development of RLLs at five and ten years after THA.MethodsA retrospective review was undertaken of 980 primary cemented THAs in 876 patients using cemented acetabular components with the IBBC technique. The outcome variable was any RLLs that could be observed around the acetabular component at the first year after THA. Univariate analyses with univariate logistic regression and multivariate analyses with exact logistic regression were performed to identify risk factors for any RLLs based on radiological classification of hip osteoarthritis.ResultsRLLs were detected in 27.2% of patients one year postoperatively. In multivariate regression analysis controlling for confounders, atrophic osteoarthritis (odds ratio (OR) 2.17 (95% confidence interval (CI), 1.04 to 4.49); p = 0.038) and 26 mm (OR 3.23 (95% CI 1.85 to 5.66); p < 0.001) or 28 mm head diameter (OR 3.64 (95% CI 2.07 to 6.41); p < 0.001) had a significantly greater risk for any RLLs one year after surgery. Structural bone graft (OR 0.19 (95% CI 0.13 to 0.29) p < 0.001) and location of the hip centre within the true acetabular region (OR 0.15 (95% CI 0.09 to 0.24); p < 0.001) were significantly less prognostic. Improvement of the cement-bone interface including complete disappearance and poorly defined RLLs was identified in 15.1% of patients. Kaplan-Meier survival analysis for the acetabular component at ten years with revision of the acetabular component for aseptic loosening as the end point was 100.0% with a RLL and 99.1% without a RLL (95% CI 97.9 to 100). With revision of the acetabular component for any reason as the end point, the survival rate was 99.2% with a RLL (95% CI 97.6 to 100) and 96.5% without a RLL (95% CI 93.4 to 99.7).ConclusionThis study demonstrates that acetabular bone quality, head diameter, structural bone graft, and hip centre position may influence the presence of the any RLL.Cite this article: Bone Joint Open 2021;2(5):278–292.

Outcomes of Cemented Distal Femoral Replacement Using “Line to Line” Technique With All-Polyethylene Tibial Implant for Tumors

BackgroundBoth cemented and cementless stemmed endoprosthetic implants have been used to reconstruct large skeletal defects after tumor resection with similar outcomes. In this study, we examined the oncologic, clinical, and functional outcomes in patients undergoing distal femur replacement using the French paradox technique. MethodsA total of 125 patients who underwent distal femur replacement between 1990 and 2019 using the line-to-line cementation technique were reviewed. Implant failure was recorded as per Henderson’s classification. Functional outcomes were analyzed using the Musculoskeletal Tumor Society and Toronto Extremity Salvage Score scoring systems. The mean follow-up was 84 (1-350) months. ResultsAseptic loosening of the femoral stem was recorded in one patient at 21-years of follow-up. Twenty of 125 patients required bushing exchange for polyethylene wear, all after 10 years. Six tibial bearing component fractures were recorded in four patients while one femoral stem component Morse taper fractured. Two all-polyethylene cemented tibial implants were revised for polyethylene granuloma. Deep surgical site infection occurred in 13 patients, while six patients experienced local recurrence. Kaplan-Meier estimates for implant survival for all-cause revision were 85% at 1 year and 70% at 5 years. These estimates for femur or tibia loosening as an end point were 96% at 10 years and 90% at 15 years. The mean Musculoskeletal Tumor Society and Toronto Extremity Salvage Score scores at the last follow-up were 76% and 74%, respectively. Thirty-five patients died of disease progression. ConclusionThe line-to-line cementation technique, used with all-polyethylene tibial implants, demonstrates low incidence of aseptic loosening at medium and long-term follow-ups. Level of EvidenceIII.

Enhancing the wear and oxidation behaviors of the Inconel 718 by low temperature aluminizing

Inconel 718 has a wide area of applications in gas turbines, aircraft, turbocharger rotor equipment, and so many other applications, including applications with temperatures up to ~700 °C. In this study, Ni-based aluminide coating on Inconel 718 alloy was applied by pack cementation technique. Phase structures, layer coating thickness, hardness, wear, and oxidation behaviors were studied for different aluminization temperatures and times (600 and 700 °C for 3 and 5 h). The change in the layer from the surface to the inside was varied from 8 to 80 μm and this was increased with higher aluminization temperature and more time. The hardness value of 960 HV was determined in the coating layer whereas the hardness of the matrix was 260 ± 10 HV. The wear resistance of the samples was tested under dry sliding conditions with different loads. The wear resistance of Inconel 718 has increased with aluminization. Increased aluminization duration and temperature reduced wear losses. Isothermal oxidation test results at 1000 °C for 5, 25, and 125 h show that Inconel 718 has a poor oxidation resistance under these conditions while aluminized Inconel 718 samples exhibit better results. The comparison of the aluminized Inconel 718 samples after oxidation tests showed that the aluminization at higher temperatures allowed the formation of a compact and continuous alumina layer while the formation of porosities under the oxide scale weakened the adherence and durability in the others. • The Inconel 718 was subjected to low temperature aluminizing at different temperatures and times. • Microstructure, wear and oxidation properties of Inconel 718 and coatings were investigated. • Aluminization improved the wear and oxidation properties of the Inconel 718 alloy. • With the increasing surface hardness, wear losses and friction coefficient decreased. • The formed Ni Al rich phases enable the formation of alumina phases during the oxidation tests.

A comparison of 2 cementing techniques in hip resurfacing using human femoral heads.

Hip resurfacing remains a valid option in young male patients. The creation of the optimum cement mantle aids fixation of the femoral component. If the cement mantle is too thick the prosthesis can remain proud leading to early failure or if it penetrates too far into the femoral head, it may cause osteonecrosis. 18 of 96 femoral heads collected from patients undergoing total hip arthroplasty were matched for their surface porosity. They were randomly allocated into 2 different cementing groups. Group 1 had the traditional bolus of cement technique, while group 2 had a modified cementing technique (swirl) where the inside of the femoral component was lined with an even layer of low viscosity cement. The traditional bolus technique had significantly greater cement mantle thickness in 3 of 4 zones of penetration (p = 0.002), greater and larger air bubble formation (6 of 9 in bolus technique vs. 1 in 9 in swirl technique, p = 0.05) and more incomplete cement mantles compared with the swirl technique. There was no relationship to femoral head porosity. The swirl technique should be used to cement the femoral component in hip resurfacing. Long-term clinical studies would conform if this translates into increased survivorship of the femoral component.

Enhanced cementation of Cd2+, Co2+, Ni2+, and Zn2+ on Al from sulfate solutions by activated carbon addition

Cadmium (Cd), cobalt (Co), nickel (Ni), and zinc (Zn) are important components of batteries and renewable energy technologies but their recovery from pregnant leach solutions or removal from polluted soil systems and water bodies remain challenging. In this study, we report the removal/recovery of heavy metal ions (Cd2+, Co2+ and Ni2+, and Zn2+) from sulfate solutions by a novel cementation technique using aluminum (Al) and activated carbon (AC) called “AC/Al-cementation”. The results showed ~0% removal/recovery efficiencies with Al only for the four heavy metals but with “AC/Al-cementation”, these values increased to 96%, 61%, 57%, and 45% for Zn2+, Ni2+, Co2+, and Cd2+, respectively. Detailed residue characterizations using SEM-EDX, XPS, and AES showed substantial deposition of heavy metal ions in their elemental forms, indicating that the primary mechanism of removal/recovery was cementation. Moreover, the results identified the critical role of AC as an electron pathway from Al (electron donor) to metal ions (electron acceptors) even though Al was covered with Al2O3. Finally, hydrogen overpotential and the subsequent passivation of cemented heavy metals by Al(OH)3 were important limiting factors and processes affecting the efficiency of “AC/Al-cementation” technique.

Aluminide coating on Mar-M246 nickel superalloy by halide activated pack cementation (HAPC)

Nickel based superalloys are widely applied in high temperatures systems because they have excellent mechanical properties. However their use over long period can lead to excessive degradation oxidation and corrosion. Protective aluminum-based coatings increase the oxidation resistance of these alloys which may be achieved using the Halide Activated Pack Cementation (HAPC) technique. In this study, the Mar-M246 nickel superalloy was coated with aluminum rich intermetallic layers, obtained by the HAPC process at 700 °C, 800 °C, 900 °C and 1000 °C, for treatment duration of 9 h. Thermodynamic calculations have been carried out previously to determine process parameters, such as the choice of the activator and the suitable temperature. The microstructural characterization of the coatings was performed by SEM and EDS analysis. The coatings obtained were uniform and homogeneous in terms composition, and free of failures and cracks containing Ni2Al3 and/or NiAl3 phases. The efficiency of the coatings to enhance the oxidation resistance of the substrate was proved through the oxidation tests carried out at 1000 °C for about 240 h in which there was the formation of protective Al2O3 scale.

Femoral Stem Cementation in Hip Arthroplasty: The Know-How of a "Lost" Art.

To describe the (1) indications, (2) preoperative precautions, and (3) stepwise technical details of modern femoral stem cemented fixation. Femoral stem cementation provides excellent implant longevity with a low periprosthetic fracture rate among patients with compromised bone quality or aberrant anatomy. Unfamiliarity with the details of modern cementation techniques among trainees who may lack frequent exposure to cementing femoral stems may preclude them from offering this viable option to suitable patients in later stages of their careers. As such, maximizing benefit from cemented femoral stem fixation among suitable candidates is contingent upon the meticulous use of modern cementation techniques. In addition to proper patient selection, modern cementation techniques emphasize the use of (1) pulsatile lavage of the femoral canal, (2) utilization of epinephrine-soaked swabs, (3) vacuum cement mixing, (4) retrograde cement introduction, (5) cement pressurization, and (6) the use of stem centralizers. Furthermore, identifying and optimizing the preoperative status of at-risk patients with pre-existing cardiopulmonary compromise, in addition to intraoperative vigilance, are essential for mitigating the risk of developing bone cement implantation syndrome. Further research is required to assess the utility of cemented femoral stem fixation among younger patients.

Comparison of adhesive bond strength among fiber reinforced post and core with different cementation techniques: In vitro study.

To investigate push-out bond strength (PBS) of fiber post to radicular dentin after using different cementation techniques. Sixty single-rooted premolars were disinfected and cleaned by mechanical instrumentation. S1, S2, and SX were used for canal shaping and finishing of the canal was carried out using F1 and F2. This was followed by constant irrigation and smear layer removal using 17%EDTA. The canal was dried filled with gutta-percha and canal space was prepared using a peso reamer. Based on cementation techniques, samples were randomly allocated into six groups. Group 1: One-step Monoblock MC; Group 2: One-step, Monoblock MC-NA (no adhesive) GFP; Group 3: One-step, RX-MC-Monoblock; Group 4: Two-step, RX-MC; Group 5: Two-step, RX-FZ; and Group 6: Two-step RX-FZ-custom post. All specimens were mounted in polyvinyl pipes using acrylic resin up to cement enamel junction. All specimens were mounted in a universal testing machine subjected to push-out forces at a speed of 0.5 mm/min. Five samples from each group were sputter-coated with 6 nm gold thickness for 300 s at 250 mA. The coated specimens were assessed under the scanning electron microscope (SEM). Analysis of variance (ANOVA) and Tukey Kramer multiple comparisons tests were performed to compare means among groups maintaining the level of significance at (p < 0.001). The highest PBS was displayed in RX-MC-Monoblock (199.020 ± 21.432 MPa). Whereas, lowest PBS was found in Monoblock MC-NA (no adhesive)-GFP (76.440 ± 9.468 MPa). Among one-step groups, RX-MC Monoblock exhibited the highest PBS (199.020 ± 21.432 MPa) comparable to one-step Monoblock MC (134.28 ± 19.37 MPa) (p > 0.05). Similarly, among two-steps groups, two-step RX-MC demonstrated significantly higher PBS values than two-step RX-FZ (143.340 ± 23.68 MPa) and RX-FZ-custom post (86.90 ± 7.41 MPa) (p < 0.05). One-step RX-MC-Monoblock technique using self-adhesive cement and core foundation composite resin material multicore flow when cured simultaneously exhibited the highest bond integrity of post retention compared to other cementation technique.

Effect of two antibacterial luting protocols with and without immediate-dentin-bonding on microtensile bond strength of glass ceramic to bur-cut cavity floor dentin

Background/Aim: The aim of this study was to evaluate the bond strength of glass ceramic inlay system using 2 antibacterial adhesive luting protocols with 2 cementation techniques to bur-cut dentin. Material and Methods: Class I inlay cavities with 6-degree occlusal divergence and size of 6-, 3and 2-mm in length, width and depth, were prepared on extracted human molars, randomly assigned to 2 main groups; each to 1 cementation technique, with or without immediate-dentin-bonding (IDB or NIDB) further divided into 3 subgroups; 2 to 2 antibacterial luting protocols, traditional (T) and experimental (E); and 1 to a control (C) group. In group IDBT, IDB-E and IDB-C dentin bonding was applied immediately after cavity preparation. In group NIDB-T, NIDB-E and NIDB-C dentin bonding was applied just before cementation of the restorations. The cavities in IDB-T and NIDB-T were treated with 2% chlorhexidine-digluconate (CHX) prior to dentin bonding application. The cavities in IDB-E and NIDB-E were treated only with dentin bonding system containing MDPB (12-methacryloyloxydodecylpyridinium bromide) active monomer featuring antibacterial effect. IDB-C and NIDB-C served as control. Dual-cure adhesive resin cement was used for the cementation of Lithium disilicatebased ceramic inlay restorations. Fourteen test specimens per group were prepared for microtensile testing and consecutively subjected to tensile load at a crosshead speed of 1 mm/min. The mode of failure was observed under SEM and evaluated for each group. The Kruskal-Wallis test was used to investigate the statistical difference between groups (a=0.05). Results: The microtensile load was 5.96 MPa (median: 5.99 MPa) for IDB-T, 7.23 MPa (median: 7.55 MPa) for IDB-E, 6.68 MPa (median: 6.56 MPa) for IDB-C, 7.24 MPa (median: 7.20 MPa) for NIDB-T, 6.98 MPa (median: 6.30 MPa) for NIDB-E, and 7.02 MPa (median: 6.99 MPa) for NIDB-C, with no statistical difference between the groups (p&gt;0.05). SEM monitoring for mode of failure revealed either cohesive (within resin cement) or adhesivecohesive (mostly within resin cement along with partially involved areas between resin cement and ceramic restoration) character. Conclusions: Within the limitations of the current study, none of the tested antibacterial luting protocols with either cementation technique was found to be superior in terms of bond strength.