Cementation Technique Research Articles

The cemented stem in hip arthroplasty - state of the art technique and recommendations.

The indication for femoral stem cementation should be made on a patient-specific basis, taking physical activity, femoral geometry, and bone tissue quality into account. Age alone should not be the sole justification for cementation. The Dorr classification can serve as decision support for whether a cemented fixation should be used. Femoral neck fractures should generally be cemented. Familiarize yourself with the applied stem philosophy. Force-closed stems typically have a polished surface that allows for subsidence, especially in the first 2 years postoperatively. Stems following the shape-closed philosophy have rougher surfaces and do not allow subsidence. There are various types of cement that differ in viscosity and can be categorized accordingly. These cement types go through four temperature-dependent phases: mixing phase, waiting phase, working phase, and curing phase. Rough implants should be implanted quickly, using wetter cement. For a polished stem, the cement should be slightly firmer. To avoid complications like bone cement implantation syndrome, it is essential to adhere to the state-of-the-art retrograde cementation technique, which recommends pulsatile lavage and vacuum mixing of the cement. Additionally, cement restrictors and pressurizers are used. A thorough understanding of cementation techniques is crucial to ensure a favorable outcome with a uniformly thick cement mantle that encompasses the entire stem. Incorrect cementing can lead to the premature failure of the endoprosthesis.

A Systematic Review Comparing the Outcomes of Cemented Versus Uncemented Stems in Femoral Impaction Bone Grafting for Revision Hip Arthroplasty.

Femoral impaction bone grafting is a crucial technique in revision hip arthroplasty, addressing bone loss and ensuring implant stability. The choice between cemented and uncemented stems significantly influences the outcomes and long-term success of the procedure. This systematic review aims to compare the clinical outcomes of cemented versus uncemented stems in femoral impaction bone grafting. A comprehensive search of PubMed, MEDLINE Complete, and the Cochrane Library databases was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies evaluating the outcomes of femoral impaction bone grafting with cemented or uncemented stems were included. The primary outcome measured was the rate of loosening of the femoral component, while secondary outcomes included the incidence of complications such as dislocation, infection, fractures, overall patient mortality, and cardiopulmonary diseases. The literature search yielded 78 articles, with 36 meeting the inclusion criteria. These included one randomized controlled trial, 16 cohort studies (10 retrospective and six prospective), and 15 case series. Most surgeries were revision procedures, with aseptic loosening being the most common indication. For the cemented technique, 1,588 hips were analyzed, with 8.00% experiencing aseptic loosening, 3.53% dislocation, 3.87% infection, 37.33% mortality, 7.57% fractures, and 1.13% cardiopulmonary complications. For the uncemented technique, 464 hips were analyzed, with 1.72% aseptic loosening, 4.74% dislocation, 1.5% infection, 38.47% mortality, 7.76% fractures, and 0.65% cardiopulmonary complications. This systematic review highlights that both cemented and uncemented techniques for femoral impaction bone grafting offer unique benefits and challenges, with the choice depending on patient-specific factors. The uncemented technique, with a lower risk of femoral component loosening, may be better suited for younger, active patients with good bone quality, despite a slightly higher risk of fractures and dislocations. In contrast, the cemented technique, offering immediate stability, is more appropriate for elderly patients with compromised bone quality but carries a higher risk of loosening and cardiopulmonary complications. The decision should be tailored to the patient's clinical profile, including age, bone quality, comorbidities, and the surgeon's expertise.

Osteoporosis May Not Be an Absolute Contraindication for Cementless Total Knee Arthroplasty

BackgroundCementless total knee arthroplasty (TKA) has received growing interest, particularly in younger populations, due to potential long-term survivability and improved bone preservation. Poor bone stock, as seen in osteoporosis, is considered a contraindication for this technique. This study evaluated whether osteoporotic patients < 75 years undergoing cementless TKA demonstrate similar 1) implant-related complications, 2) medical complications, 3) readmission rates, and 4) 3-year implant survivability. MethodsA retrospective query of a national administrative claims database was performed between 2010 and 2022 for patients less than or equal to 75 years old who have osteoporosis and underwent primary TKA. Osteoporotic patients were divided into cementless and cemented cohorts, and propensity scores were matched based on age, sex, obesity, and the Charleston Comorbidity Index (CCI). Matching produced 7,923 patients (1,321 uncemented, 6,602 cemented). Multivariate logistic regressions evaluated the following outcomes: 90-day and 2-year implant-related complications, 90-day postoperative medical complications, and 90-day readmissions. Kaplan-Meier survival analysis was conducted to assess 3-year all-cause revision implant survivability. The significance threshold was set to P < 0.01 to minimize type 1 bias. ResultsThere were no statistically significant differences in implant-related complications, medical complications, readmissions, and lengths of stay between cementless and cemented TKA groups. Kaplan-Meier analysis demonstrated statistically similar 3-year survivability between cohorts (cemented: 97.6%, CI [confidence interval] 96.6 to 98.5; cementless: 97.2%, CI 96.7 to 97.7; P = 0.472). ConclusionPatients who have osteoporosis have equivalent medical and implant-related complications as well as 3-year implant survival following cementless TKA compared with a cemented technique. Our results support cementless TKA as a viable option for patients < 75 years, regardless of prior diagnosis of osteoporosis. Intraoperative decisions regarding bone quality are still necessary to discriminate between those who are candidates for cementless TKA with those who are not.

Comparison of different cementing techniques for cement penetration under tibial component in total knee arthroplasty: a retrospective observational study

PurposeThis study aimed to investigate the differences in cement penetration between cementing techniques in total knee arthroplasty (TKA).Materials and methodsWe retrospectively evaluated knee undergone TKA at our hospital for both preoperative and postoperative computed tomographic (CT) evaluations. Cementing was performed with hand mixing and hand packing (HM group) and with vacuum mixing and cement gun use (VM group). We measured the area under the tibial baseplate (sclerotic and nonsclerotic sides) and compared the mean and maximum depths of cement penetration at each area.ResultsOf the 44 knees evaluated, 20 and 24 knees were in the HM and VM groups, respectively. At the center of the sclerotic side, the mean penetration depths (2.0 ± 0.7 and 2.5 ± 0.7 mm, p = 0.02) and the maximum penetration depths (4.0 ± 0.9 and 5.0 ± 1.6 mm, p = 0.02) were significantly deeper in the VM group than in the HM group. The correlation between preoperative Hounsfield unit values and mean penetration were r = –0.617 (p < 0.01) and –0.373 (p = 0.01) in the HM and VM groups, respectively.ConclusionThe cementing technique of vacuum mixing and using a cement gun allowed for deeper cement penetration compared with the hand mixing and hand packing technique, even in bone sclerotic sites.

Evaluation of pulp chamber temperature during cementation with the preheated composite resin technique

The cementation technique using preheated composite resin requires high temperatures for optimal execution and may lead to increased and damaging intrapulpal temperatures. Whether the technique can lead to a temperature increase that might lead to necrosis of the pulp tissue is unclear. The purpose of this in vitro study was to evaluate the temperature variation in the pulp chamber of bovine teeth with veneer-type preparations during veneer cementation using the preheated composite resin technique. A total of 103 bovine incisors were divided into 8 groups (n=10) and prepared for indirect veneers with different preparation depths: 2.0mm, 1.5mm, 1.0mm, and 0.5mm. Veneers were cemented on these preparations using 2 cementation protocols: preheated composite resin and photopolymerizable resin cement. The teeth were attached to a device containing a temperature sensor which was inserted into the pulp chamber to quantify the intrapulpal temperature variation produced during the cementation protocols. The data were analyzed using a statistical software program. The level of statistical significance for the analyses was with a confidence interval of 95%, sampling power of 80%, and a moderate effect size (0.36). The groups cemented with preheated composite resin and the groups with the greatest preparation depth had the highest mean intrapulpal temperature; the PHC2 group presented a mean ±standard deviation temperature increase of 5.70 ±2.14°C. The heat generated by heating the resin contributed to the increase in intrapulpal temperature. Temperature variations were greater in deeper preparations, especially when preheated resin technique was used.

Total Femur Replacement as a Salvage Procedure for Failed Distal Femur Megaprosthesis: A Case Report and Literature Reviews

Abstract Total femoral replacement (TFR) is not a common surgery and most indications are for oncological pathologies. However, there are few instances where non-oncological indications might necessitate TFR; this may be a salvage surgery for failed previous hip and/or knee surgeries with consequent significant femur bone loss. We present a 59-year-old obese woman with right thigh pain and difficulty with walking of 5 years duration. She had undergone bilateral total knee replacement 10 years earlier on account of severe knee osteoarthritis. She had a fall 3 years prior to presentation and sustained a periprosthetic fracture around the right knee which was managed with a fixed angle blade plate and screws. This was complicated by implant breakage and non-union. She subsequently had implant removal and a right distal femur replacement (DFR) surgery 2 years prior to presentation. A year after the DFR surgery, she began to experience “start-up” pain, instability around the knee and difficulty with walking without support. A clinical and radiologic diagnosis of aseptic loosening of the distal femur megaprosthesis was made and she was offered a revision DFR surgery which also failed due to poor cementing technique, bone loss at the proximal femur, and severe osteoporosis. Patient ended up with a right total femur replacement to salvage the limb. She had improved Lower Extremity Functional Score of 27 after 12-month follow-up. TFR is a viable salvage procedure for severely compromised femur and/or significant bone loss from multiple non-oncological surgeries of the femur.

Debunking Deterministic Narratives of Technological Development Through Experimentation: A Critical Review of the Prehistory of Tin Bronze Alloying

The currently accepted narrative on the prehistory of bronze alloying technology follows deterministic, outdated assumptions of technological progression that ignore the role of contextual and performance factors in the decision-making processes, thus neglecting human agency. In essence, it is expected that newer techniques were overarchingly more advanced than older ones and hence replaced them. The validity of this narrative should be challenged and revised. A critical analysis of worldwide literature exposed that, contrary to predictions of the accepted theory, (1) the oldest alloying techniques persisted for centuries after newer ones were invented, and (2) several techniques usually coexisted in the same contexts. We hypothesised that these counterintuitive findings could be explained by differences in performance between techniques, (dis)advantageous at different settings. To obtain empirical information on the performance of techniques and test for behaviourally relevant performance differences between them, a series of alloying experiments were conducted. The results show that all techniques can produce objects of broadly equivalent quality while offering different trade-offs during production. Therefore, every technique—or a combination—can be advantageous under certain conditions, and there are no grounds to support a linear trajectory of substitution. These results debunk the traditional narrative and predict that co-smelting and cementation techniques were more frequently practiced in the past than hitherto assumed. Our propositions prompt a readjustment of explanatory models of bronze production organisation, trade, and consumption while opening unexplored research paths for archaeology and the history of technology.

Shear bond strength in two types of indirect orthodontic cementation.

To compare the shear bond strength of brackets cemented to dental enamel according to the cementation techniques. Experimental study. We used 90 premolars and placed them in printed polylactic acid (PLA) filament models to simulate the dental arch shape and to then cement brackets using the direct, indirect technique with Transbond™XT and indirect technique with Orthocem®. Then, we carried out a shear bond strength test using a universal testing machine, and we evaluated the enamel surface using the adhesive resin remaining index. Dunn's test was used for the inferential statistical analysis of shear bond strength, and Fisher's exact test was used for the adhesive resin remaining index. The shear bond strength of the brackets recorded mean values of 16.74±4.48Mpa, 15.93±6.49Mpa and 12.09±5.07Mpa in the direct, indirect technique with Transbond™XT and indirect technique with Orthocem® respectively. At an inferential level, a lower statistically significant difference was found in the indirect group with OrthoCem® in contrast to the other two groups. In the evaluation of resin remaining after detachment, the direct technique group registered 46.7% of teeth with more than half of resin remaining and the indirect technique groups with Transbond™XT and Orthocem® registered less than half of resin remaining with an incidence of 53.3% and 43.3% respectively. At an inferential level, a statistically significant difference between groups was evidenced. The indirect cementation technique using Transbond™ XT is more recommended since it presents a higher shear bond strength than using Orthocem®. Key words:Orthodontics, Adhesion, orthodontic adhesives, shear bond strength.

Complications of revision knee arthroplasty

Due to the growing scale of arthroplasty and the widening of indications for knee joint replacement, the durability of joint functioning has become a critical issue. Untimely diagnosis and inadequate treatment of patients with endoprosthesis component loosening leads to major bone defects. This problem arises from repeated joint interventions, large bone defects and duration of revision surgeries, that is fraught with catastrophic consequences for patients – revision prosthesis removal or even limb amputation. The project aims to improve the treatment for patients with instability of components after knee joint arthroplasty. The aim of the study is to analyze the results of revision knee arthroplasty and identify the causes of mistakes and complications of revision arthroplasty with the intention of prevention. Materials and methods. A retrospective analysis of 50 revision knee arthroplasties performed at the Centre for Arthroplasty of the State Institution “Institute of Traumatology and Orthopedics of the National Academy of Medical Sciences of Ukraine” was conducted. Clinical and radiological findings were evaluated for all patients. All revision prostheses used in this study were of the semi-constrained type. Cementation technique was used for all implants. In the revision of the septic complication group, a full cementation technique with antibiotics according to a sensitivity profile were used, while in the aseptic complication group, a surface cementation technique with antibiotics according to sensitivities were used. Results. The authors of the project have analyzed the results of treatment of 50 revision arthroplasty procedures performed between 2013 and 2022 for instability of the endoprosthesis components. The structure of complications has been examined and the causes of failure in revision knee arthroplasty have been identified. This study has shown promise in preventing complications and developing personalized approaches to revision arthroplasty. Conclusions. The analysis of revision knee arthroplasty failure has shown the prevalence of septic complications (56.0 %). In the case of septic complications after revision arthroplasty, Staphylococcus aureus prevailed (57.1 %), gram (-) microorganisms were causative agents in other cases. Factors resulting in aseptic complications included those associated with the surgical intervention (81.8 %), the patient (45.4 %) and the combination thereof (72.7 %). Significant causes of the femoral revision component loosening were residual valgus deformity, medial instability in the frontal plane; significant causes of the tibial component loosening were residual varus deformity and lateral instability in the frontal plane.

Mass balance and economic study of a treatment chain for rare earths, base metals and precious metals recovery from used smartphones

In the present study, a comprehensive hydrometallurgical process was developed for the recovery of several types of metals from used cell phone printed circuit board assemblies. The overall process is divided into four stages of selective leaching of rare earth elements (REE), copper, nickel, silver and finally gold. After solubilization, the metals were purified using precipitation, solvent extraction, electrodeposition, and cementation techniques. Laboratory pilot-scale tests of the complete smart phone printed circuit board processing line showed REE, copper, nickel, silver, and gold recovery efficiencies of 78.0 %, 98.8 %, 81.8 %, 100 % and 96.1 %, respectively. The purity of the products obtained is evaluated at 94.8 % for rare earth oxides (70.0 % Nd2O3, 18.5 % Pr2O3, 2.8 % Dy2O3 and 2.4 % Sm2O3), 99.8 % for elemental copper, 94.3 % for nickel oxide, 93.8 % for silver and 89.3 % for gold. A scenario involving the installation of a plant processing 1 t/h of waste was evaluated using SuperPro Designer software. For a total investment of $53.22 million and an operating cost of $18.23 million per year, the main revenue is $65.77 million per year, with a return on investment of 91.6 % and a payback period of 1.1 years.

Functional and Radiological Outcomes of a Newly Introduced Modified Manual Cementation Technique Versus Second-Generation Technique in Primary Cemented Hip Arthroplasty

Abstract Background: Hip arthroplasty is one of the most common reconstructive procedures done in adults.[1] The main purpose of this surgery is to eliminate pain, regain full extent of joint motion, maintaining hip stability, and improve the quality of life for patients. Objectives: This work aims to compare the clinical and radiological outcomes of two techniques; the second-generation cementation technique and a newly introduced modification of the manual technique in primary cemented hip arthroplasty. Patients and Methods: This prospective, randomized clinical trial included 44 patients. Patients were allocated into two equal groups: the case Group A; who had primary hip arthroplasty operation with the modified manual cementation technique and the control Group B; who had arthroplasty using the second generation cementation technique. The average follow-up period was about 12 months after the operation. Operation time, intraoperative parameters, postoperative clinical and radiological outcomes, and complications were compared between the two groups. Results: The operation duration was significantly longer in Group B (123.4 ± 9.0 vs. 107.5 ± 15.2, P = 0.001). No intraoperative complications were found among 77% while 13.6% showed allergic reaction to cementation 72% of them are in Group B, 6.8% needed blood transfusion, and 2.3% had pulmonary embolism on cementation. No significant difference between the two studied groups regarding postoperative Visual Analog Scale (VAS) score,[2] barrack grading,[3] complications and Harris hip score[4] at 3 months, 9 months, and 12 months was noted. Conclusion: In conclusion, this study concluded that Group A the newly introduced modified manual cementation technique might provide a cheaper and effective alternative to Group B the second-generation technique, with relatively less intraoperative complications and almost no difference in postoperative VAS, Harris hip score, and radiological outcomes over a period of 1-year follow-up.

Purification of Mn-Electrolyte Solution from Leaching of Zn-MnO2 Spent Batteries Using Cementation Technique

Purification of Mn-Electrolyte Solution from Leaching of Zn-MnO2 Spent Batteries Using Cementation Technique

Effects of cementation technique and cement thickness on the retention and amount of excess cement in implant-supported restorations

PurposeTo assess the amount of excess cement and the retentive strengths of two different cementation techniques (conventional cementation and practice abutment) using copings fabricated with three different cement thicknesses (20 μm, 35 μm, and 50 μm). Materials and methodsThirty zirconia copings were fabricated on screw retained abutments and randomly divided into three equal groups (n = 10) according to the cement thickness (20 μm, 35 μm, and 50 μm). Each group was cemented with tow cementation techniques. Cementation was performed with provisional cement (Temp-Bond). In the conventional cementation technique, cement was applied until each coping was approximately half filled, and the copings were subsequently placed on the implant–abutment assembly. Then, the copings were cleaned and cemented using the practice abutment cementation technique to remove excess cement prior to the process. Each technique was performed using copings with three different cement thicknesses (20 μm, 35 μm, and 50 μm). The specimens with the cemented copings were weighed on a high-precision analytical balance before and after removing the extruded cement, and the differences between the two measurements were calculated. Then, each specimen was subjected to a pullout test using a universal testing machine. The load required to dislodge the coping was recorded. The data were analyzed using two-way and one-way analysis of variance and independent sample t tests at a significance level of 0.05. ResultsThe highest retention values were obtained for 20 μm cement thickness in the conventional technique and the practice abutment cementation technique. The amount of excess cement was the highest for the 50 μm cement thickness obtained for both cementation techniques, whereas the lowest mean values were recorded for the 20 μm cement thickness. ConclusionThe conventional cementation technique is recommended over the practice abutment technique to increase the retention of crowns cemented with provisional cement. However, care must be taken to remove the extruded cement. A cement thickness of 20 μm is preferable for enhancing the retention of cemented crowns and for reducing the amount of excess cement when applying both conventional and practical abutment cementation approaches.

Marginal Leakage in Interfaces Formed by Bovine Dentin and Adhesive Cements Applied with Different Bonding Techniques

Objectives: The aim of this in vitro study was to evaluate the marginal microleakage in interfaces formed by bovine dentin and adhesive cements applied with different bonding techniques. Materials and Methods: Thirty bovine teeth dentin blocks measuring 5 mm x 5 mm x 1 mm were made with one side completely in dentin substract (20 mm2). The dentin blocks were randomly divided into three groups according to the cementation technique used: CTS+RX (conventional 3-step adhesive + dual-activation resin cement), SBS+RX (single-bottle self-etching adhesive + dual-activation resin cement), and SAC (self-adhesive cement). A photopolymerizable composite resin block with the same dimensions was fixed on the dentin block according to the instructions for each adhesive technique. The dentin-composite resin blocks made with each adhesive technique were separated into subgroups (n = 5) for 7 days (control) and for 6 months of water storage. After each period, the blocks were individually immersed in test tubes containing neutral methylene blue dye for 2 hours. The samples were washed, dried, and evaluated with a stereoscopic magnifying glass, and the amount of infiltrated pigment was analyzed using spectrophotometry (Beckman DU 65). The data were submitted to two-way ANOVA and Tukey’s test (5%). Results: Microleakage level for the conventional 3-step or self-etching technique remained similar for 7 days (18 ± 25 and 43 ± 45 μm, respectively) or 6 months (42 ± 55 and 52 ± 87 μm, respectively). The self-adhesive technique showed higher microleakage levels for 7-day (263 ± 98 μm) and 6-month periods (441 ± 226 μm) compared to other adhesive techniques. There was a statistically significant difference between evaluation times only for the self-adhesive technique. Conclusions: Higher microleakage levels by storage in water occurred with the self-adhesive technique in both evaluation periods. Clinical Relevance: The different microleakage levels promoted at the dentin-composite resin interface should be considered in adhesive clinical procedures in relation to long-term use.

Early results of the combined grafting–cementation technique for the treatment of giant cell tumors with a large subchondral bone defect: a case series

Background Giant cell tumor (GCT) is a rare, locally aggressive bone tumor. It typically affects young adults close to the joints, mainly the knee joint. The high recurrence rate, along with erosion of the subchondral bone complicates the surgical plan. Current treatment standards involve extended curettage followed by space-filling by cement or graft. We present a detailed technique using a combined technique using both bone graft and cement for reconstructing GCT-related subchondral damage. Patients and methods Eighteen patients underwent surgery from January 2018 to December 2021. The surgery involved extended curettage using a high-speed burr, and lavage using hydrogen peroxide. Placement of the graft as a subchondral shelf helps to support the articular cartilage. Bone cement was applied to fill the cavity and support the graft; internal fixation was used in large-sized lesions. Results The mean follow-up is 34.5 months. Oncologically, local recurrence was reported in one case, with a distal radius location, and no distant metastasis was reported. Functionally, 86.6% had excellent/good Musculoskeletal Tumor Society score scores. Graft union had occurred in all cases; mean union time was 12 weeks. Rehabilitation included immediate passive range of motion exercises and partial weight bearing. The pain had improved significantly in all cases. Muscle power had been temporarily affected in five cases. One patient had a wound infection, managed with antibiotics. Conclusion Treatment of GCTs is challenging. The standard treatment involves curettage and gap filling. The presence of the cement close to the articular cartilage can lead to osteoarthritis due to different modulus of elasticity. We describe this combined technique to provide support, insulation, and stability, and minimize the stresses on the articular cartilage. The results of this technique are promising and yield good functional and oncological outcomes. Further research is needed to evaluate its long-term efficacy in preventing progressive osteoarthritis.

Comparative Test of Reconstruction with the Modified Arthrodesis Metallic and Cement (MAMC) Technique and the Juvara Technique in Resisting Axial Compression After Distal Femur Resection

Background: Limb salvage surgery (LSS) is a crucial treatment for malignancies, which mostly affects the distal femur and proximal tibia. LSS encompasses biological and non-biological reconstructions, including megaprosthesis. However, limited access to megaprosthesis in developing countries has led to alternative methods like arthrodesis such as modified arthrodesis with metal and cement (MAMC). LSS may lead to complications, requiring careful technique and implant selection but none of them conduct research about mechanical test. This research was comparing the effectiveness of techniques like MAMC with Juvara, in mechanical axial loading perspective. &#x0D; Methods: In this true experimental study, conducted at the Metallurgy Laboratory of the Faculty of Engineering, Universitas Sriwijaya, femur and tibia bones from cattle were used. Five samples of each variable were used based on the purposive sampling method. The research focused on variables like deformity angle and yield point which assessed using X ray. Bone constructs underwent various fixation techniques, including MAMC and Juvara. Testing involved axial pressure on the femur head using a mechanical press machine. Statistical analysis compared implant angulation after compression between Juvara and MAMC techniques under 30 kg and 60 kg loads, ultimately measuring the yield point.&#x0D; Results: All five samples from each group, subjected to both 30kg and 60kg pressure, exhibited no discernible changes. The average yield point for the MAMC group was notably 160KgF higher than Juvara, with respective means of 296 and 126kgF (p&gt;0.05). Further analysis employing an Independent T-test confirmed a significant disparity between the MAMC and Juvara techniques concerning the yield point with a p-value of &lt;0.001. &#x0D; Conclusion: Both the MAMC and Juvara techniques in this study effectively supported 30 and 60-kilogram loads, demonstrating their suitability for full weight-bearing compression, with MAMC exhibiting significantly greater compression resistance compared to Juvara (p = 0.001).

The Effect of Various Preparation and Cementation Techniques of Dental Veneers on Periodontal Status: A Systematic Review and Meta-Analysis.

Dental veneers are widely used to restore or/and enhance dental aesthetics. However, it is not well understood how various veneer preparation and cementation methods affect periodontal health. To provide a quantitative estimate of the overall effect size of the intervention, this study was conducted to synthesize the available evidence on the impact of various dental veneer preparation and cementation methods on periodontal status. A thorough search strategy was implemented using Medical Subject Headings keywords and Boolean operators across various major databases, guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. Nine papers were ultimately selected for inclusion in the review. Seven studies demonstrated a positive impact of dental veneers on overall periodontal health, while two studies reported a slight worsening. The forest plot analyses showed a somewhat protective effect of dental veneers on periodontal health, with odds ratio of 0.18 and relative risk of 0.34, suggesting that dental veneers may have a positive impact on overall periodontal health. The current study, with considerable heterogeneity among the studies, indicates that dental veneers are associated with an overall positive effect on the periodontal health. However, given the variations in study designs, sample sizes, and follow-up times, additional research may be required to confirm and generalize these results.

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

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

Reverse total shoulder arthroplasty with proximal bone loss: a biomechanical comparison of partially vs. fully cemented humeral stems

BackgroundThe appropriate amount of cementation at the time of reverse total shoulder arthroplasty with significant proximal bone loss or resection is unknown. Extensive cementation of a humeral prosthesis makes eventual revision arthroplasty more challenging, increasing the risk of periprosthetic fracture. We analyzed the degree of subsidence and torque tolerance of humeral components undergoing standard cementation technique versus our reduced polymethyl methacrylate (PMMA) protocol. Reduced cementation may provide sufficient biomechanical stability to resist physiologically relevant loads, while still permitting a clinically attainable torque for de-bonding the prosthesis. MethodsA total of 12 cadaveric humeri (6 matched pairs) underwent resection of 5 cm of bone distal to the greater tuberosity. Each pair of humeri underwent standard humeral arthroplasty preparation followed by either cementation using a 1.5 cm PMMA sphere at a location 3 cm inferior to the porous coating or standard full stem cementation. A 6-degrees-of-freedom (DOF) robot was used to perform all testing. Each humeral sample underwent 200 cycles of abduction, adduction, and forward elevation while being subjected to a physiologic compression force. Next, the samples were fixed in place and subjected to an increasing torque until implant-cement separation or failure occurred. Paired t-tests were used to compare mean implant subsidence versus a predetermined 5 mm threshold, as well as removal torque in matched samples. ResultsFully and partially cemented implants subsided 0.49mm (95% CI, 0.23 to 0.76 mm) and 1.85mm (95% CI, 0.41 to 3.29 mm), respectively, which were significantly less than the predetermined 5mm threshold (p<0.001 and p<0.01, respectively). Removal torque between fully cemented stems was 45.22 Nm (95% CI, 21.86 to 68.57 Nm), versus 9.26 Nm (95% CI, 2.59 to 15.93 Nm) for partially cemented samples (p=0.021). Every fully cemented humerus fractured during implant removal versus only one in the reduced cementation group. The mean donor age in our study was 76 years (range, 65 to 80 years). Only one matched pair of humeri belonged to a female donor with comorbid osteoporosis. The fractured humerus in the partially cemented group belonged to that donor. ConclusionPartially and fully cemented humeral prostheses had subsidence that was significantly less than 5 mm. Partially cemented stems required less removal torque for de-bonding of the component from the cement mantle. In all cases, removal of fully cemented stems resulted in humeral fracture. Reduced cementation of humeral prostheses may provide both sufficient biomechanical stability and ease of future component removal.

Combination of cellulose nanofiber and artificial fusion protein for biocementation

Biomineralization occurring in living organisms is mostly controlled by organic macromolecules such as polysaccharides and proteins. Recently, biomineralization has been attracting much attention as a green and sustainable cementation technique including enzyme-induced carbonate precipitation (EICP), where CaCO3 is formed by hydrolysis of urea by urease in the presence of calcium ions. In this study, we have developed a novel hybrid biocementation method combining CaCO3 and cellulose nanofiber (CNF). In nature, matrix proteins work as a binder at the interface of organic and inorganic materials to form hybrid biomaterials. By mimicking the natural system, we designed an artificial fusion protein to facilitate the deposition of CaCO3 on CNF. Calcite-binding peptide (CaBP) and carbohydrate-binding module (CBM) were introduced in the artificial fusion protein CaBP-CBM to connect CaCO3 and cellulose. The addition of CNF in the EICP system resulted in the formation of a number of small particles of CaCO3 compared to a non-additive system. The addition of the fusion protein CaBP-CBM to CNF led to an increase in the size of CaCO3 particles. Furthermore, the combination of CaBP-CBM and CNF provides higher strength of samples in sand solidification. Therefore, introduction of CNF and the fusion protein would be promising for novel biocementation techniques.