Cementation Technique Research Articles

Fat Embolism and Fat Embolism Syndrome.

Fat embolism (FE) occurs frequently after trauma and during orthopaedic procedures involving manipulation of intramedullary contents. Classically characterized as a triad of pulmonary distress, neurologic symptoms, and petechial rash, the clinical entity of FE syndrome is much less common. Both mechanical and biochemical pathophysiologic theories have been proposed with contributions of vascular obstruction and the inflammatory response to embolized fat and trauma. Recent studies have described the relationship of embolized marrow fat with deep venous thrombosis and postsurgical cognitive decline, but without clear treatment strategies. Because treatment is primarily supportive, our focus must be on prevention. In trauma, early fracture stabilization decreases the rate of FE syndrome; however, questions remain regarding the effect of reaming and management of bilateral femur fractures. In arthroplasty, computer navigation and alternative cementation techniques decrease fat embolization, although the clinical implications of these techniques are currently unclear, illustrating the need for ongoing education and research with an aim toward prevention.

The Effect of Tourniquet Use and Sterile Carbon Dioxide Gas Bone Preparation on Cement Penetration in Primary Total Knee Arthroplasty

BackgroundTourniquetless total knee arthroplasty (TKA) is experiencing resurgence in popularity due to potential pain control benefits. Furthermore, optimal cement technique and implant fixation remain paramount to long-term cemented TKA success, as aseptic loosening continues to be a leading cause of revision. The purpose of this study is to determine how tourniquet use and/or novel bone preparation using sterile, compressed carbon dioxide (CO2) gas affected cement penetration in TKA. MethodsA retrospective review was performed on 303 consecutive primary TKAs with the same implant in 3 groups: (1) a tourniquet without sterile CO2 compressed gas used for bone preparation, (2) no tourniquet with CO2 gas, and (3) tourniquet use and CO2 gas bone preparation. Cement penetration was measured on radiographs by two independent, blinded raters across 7 zones defined by the Knee Society Radiographic Evaluation System. ResultsThe 3 groups did not differ on age, body mass index, or gender (P ≥ .1). Cement penetration was greater in 6 of 7 zones with significantly greater cement penetration in 3 zones (tibial anteroposterior zone 2, femoral lateral zones 3A and 3P) in groups that utilized CO2 gas bone preparation compared to the tourniquet only group (P ≤ .039). ConclusionBone prepared with CO2 gas showed significantly more cement penetration in 3 zones with greater cancellous bone. The results suggest that use of CO2 gas bone preparation may achieve greater cement penetration than using a tourniquet with lavage only.

Microstructure and tribological properties of Si-Y/Al two-step deposition coating prepared on Ti2AlNb based alloy by halide activated pack cementation technique

Abstract To enhance the tribological properties of the Ti2AlNb based alloy, a Si-Y/Al coating was prepared by a two-step halide activated pack cementation process including Si-Y co-deposition first and then aluminization. The Si-Y coating and the Si-Y/Al coating both had multilayer structures. After the aluminization, the microhardness of the Si-Y/Al coating decreased a little, but was still much higher than that of the substrate. Its toughness was obviously improved. The tribological properties of the bare alloy, the Si-Y coating and the Si-Y/Al coating were comparatively studied at room temperature and 873 K using SiC balls as the counterparts. The results showed that the Si-Y/Al coating could provide better protection for the Ti2AlNb based alloy than the Si-Y coating.

Evaluation of Yttria Coated High Density Graphite with Silicon Carbide Interlayer for Uranium Melting Applications

Abstract Yttrium Oxide (Y2O3) deposited over High Density Graphite (HDG) by Atmospheric Plasma Spray (APS) process is highly desirable as a chemical barrier coating for reusable Uranium (U) melting crucibles in the pyrochemical reprocessing of spent metallic fuels. In the present study, an oxidation protective Silicon Carbide (SiC) interlayer coating over HDG has been achieved by pack cementation process. The high-temperature oxidation resistance and resistance to thermal fatigue failure of Y2O3 coating with and without SiC interlayer were evaluated by performing repeated thermal cycling studies at 1450, 1500 and 1550 °C. The durability performance of Y2O3 coating with SiC interlayer in the actual working environment was simulated by performing U melting studies using miniature size HDG coated crucibles. The microstructural, chemical and phase characterization of coatings prior and post thermal cycle failure were carried out by SEM/EDS and XRD techniques. It is observed that the SiC interlayer developed by novel pack cementation technique for the Y2O3 top coat extended the thermal cycling and life of the coating with U melting in inert argon gas environment significantly. The occurrence of micro-cracking over Y2O3 top coat with SiC interlayer perceived after 33, 30 and 25 thermal cycles at 1450, 1500 and 1550 °C, respectively.

Preparation of titanizing coating on AISI 316 stainless steel by pack cementation to mitigate surface damage: Estimations of corrosion resistance and tribological behavior

In this study, a titanizing coating was prepared on AISI 316 stainless steel (316 SS) using the pack cementation technique at 1173 K for 6 h. The microstructural characteristics and surface hardness of the titanizing coating were systematically analyzed. The bonding strength between the titanizing coating and the 316 SS substrate was also measured. Comparative assessments of the corrosion resistance and tribological behavior of the titanizing coating and 316 SS were conducted. The results showed that the coating was compact and uniform, and it reached a thickness of 5 μm. The concentration of Ti exhibited a gradient distribution along the titanizing coating. Titanizing enhanced the surface hardness of the 316 SS and the coating obtained was strongly bonded with the 316 SS substrate. As expected, the titanizing coating exhibited better anti-corrosion properties than the bare 316 SS. The titanizing coating also provided considerable protection to the 316 SS in friction-wearing tests. The excellent anti-corrosion and wear resistance properties of the titanizing coating were due to its high chemical stability, hardness, and bonding strength. The titanizing treatment may allow the production of a working surface on 316 SS with improved anti-corrosion and wear resistance properties.

Microstructure and Oxidation Behavior of Cobalt Diffusional Coating Fabricated on AISI 429 Stainless Steel

The best candidates for interconnects in solid oxide fuel cells are chromia-forming alloys. However, the low oxidation resistance of these materials needs to be solved to obtain better performance of the interconnect. The aim of this study was to coat AISI 429 ferritic stainless steel with a cobalt-based layer using pack cementation technique. For investigating the oxidation behavior of the coated and uncoated AISI 429 steel, three types of oxidation tests were conducted: isothermal oxidation at 750 °C; cyclic oxidation at 750 °C; and oxidation at different temperatures (400–900 °C). The cobalt-based coating and oxide scales formed were studied by X-ray diffraction and scanning electron microscopy. The cobalt-based coating converted to Co3O4, CoFe2O4, and CoCr2O4 spinels during oxidation exposure. The results showed that the cobalt spinels improved oxidation resistance through the decrease in Cr2O3 growth.

Effect of dentin pretreatment on shear bond strength of three resin-based luting cements.

The aims of this study were; to compare the shear bond strength values of resin-based luting cements using etch-and-rinse, self-etching or self-adhesive techniques and to evaluate the effects of pretreatment with 0.2%, and 2% chlorhexidine (CHX) solutions on the bonding stability to dentin. Ninety specimens were divided into 9 groups of equal sample size (0.2% CHX, 2% CHX and no CHX application groups). Variolink N (multi-step etch-and-rinse technique), Panavia F2.0 (self-etching technique), or RelyX U200 (self-adhesive technique) resin-based luting cement was applied. All specimens were subjected to shear bond strength test (SBS) after bonding procedure. The mode of failure was analyzed by using a stereomicroscope. There were no significant differences among study groups for the dentin treatment factor. However, for luting cement factor, significant differences were found and Variolink N showed the highest SBS values. CHX application has no immediate effect on the SBS values of any resin cements. Despite the development of simplified cementation techniques, etch-and-rinse technique is still the most reliable technique because of its high bond strength to dentin.

Effect of a preseating cementation protocol on the retention of implant restorations using a definitive cement

Purpose: This investigation analyzed the effects of a preseating cementation protocol on the amount of cement excess at the crown margin and its associated tensile load using a glass ionomer definitive cement. Materials and Methods: The independent variable in this study was the cementation technique. The first protocol involved a conventional cementation procedure and the second one preseating on an abutment replica. Ten metallic copings were cemented using a definitive cement on ten implant abutments for each cementation protocol. Cement excess at the margin was weighted (mg), and axial tensile load was measured 24 h after cementation. Results were statistically analyzed using linear regression and one-way analysis of variance (α = 0.05). Results: The cementation protocol with preseating resulted in a significantly smaller amount of cement excess at the crown margin (P ≤ 0.001) without detriment on the tensile resistance when compared to the experimental group without preseating (P = 0.41). Linear regression failed to prove any correlation between the amount of cement excess and tensile load necessary for dislodgement. Conclusions: A preseating protocol can be performed when using a definitive cement. This procedure reduces significantly the amount of cement excess at the margin while maintaining an acceptable tensile load resistance.

Screw Retention with Cementation Technique : Improving Passivity of the Esthetic Superstructure Using a Combination of Screw Retention and Cementation

Screw Retention with Cementation Technique : Improving Passivity of the Esthetic Superstructure Using a Combination of Screw Retention and Cementation

The effect of individualization of fiberglass posts using bulk-fill resin-based composites on cementation: an in vitro study.

ObjectivesThis study evaluated the bond strength of various fiberglass post cementation techniques using different resin-based composites.Materials and MethodsThe roots from a total of 100 bovine incisors were randomly assigned to 5 treatment groups: G1, post + Scotchbond Multi-Purpose (SBMP) + RelyX ARC luting agent; G2, relined post (Filtek Z250) + SBMP + RelyX ARC; G3, individualized post (Filtek Z250) + SBMP; G4, individualized post (Filtek Bulk-Fill) + SBMP; G5, individualized post (Filtek Bulk-Fill Flow) + SBMP. The samples were subjected to the push-out (n = 10) and pull-out (n = 10) bond strength tests. Data from the push-out bond strength test were analyzed using 2-way analysis of variance (ANOVA) with the Bonferroni post hoc test, and data from the pull-out bond strength test were analyzed using 1-way ANOVA.ResultsThe data for push-out bond strength presented higher values for G2 and G5, mainly in the cervical and middle thirds, and the data from the apical third showed a lower mean push-out bond strength in all groups. No significant difference was noted for pull-out bond strength among all groups. The most frequent failure modes observed were adhesive failure between dentine and resin and mixed failure.ConclusionsFiberglass post cementation using restorative and flowable bulk-fill composites with the individualization technique may be a promising alternative to existing methods of post cementation.

Oxidation protection of C/C composites: Coating development with thermally stabile SiC@PyC nanowires and an interlocking TaB2-SiC structure

To improve the thermal stability of SiC nanowires at ultra-high temperatures, pyrolytic carbon (PyC) is deposited on them by chemical vapor deposition. The results suggest that the PyC can effectively protect nanowires from phase transition and crystal growth up to 2373 K. Meanwhile, a PyC-coated SiC (SiC@PyC) nanowire-reinforced interlocking zigzag interface is designed and constructed between TaB2-SiC coating and carbon/carbon (C/C) composites. Due to more survivals of nanowires and the constructed zigzag interface, adhesion strength of TaB2-SiC coating is enhanced. During the thermal cycling test between 1873 K and room temperature in air, SiC@PyC nanowire-reinforced interlocking TaB2-SiC coating prepared by pack cementation (PC) technique, exhibits good oxidation-resistant performance. The alleviation of coefficient of thermal expansion and the buffering roles of PyC effectively decrease the thermal stress of TaB2-SiC coating and restrain the formation of microcracks. These results can provide useful information for nanomaterial-reinforced ceramics and ceramic coatings to be employed at ultra-high temperatures.

Effect of cement application techniques on the adaptation and retention of provisional crowns.

A well-made and properly cemented provisional restoration is essential for the health of abutment teeth and periodontium. Few focused studies are available on the effect of cementation techniques on the fit as well as on the retention of the provisional crowns. To investigate the effect of six cement application techniques on the adaptation and retention of provisional crowns. Seventy-two provisional crowns (Bisacryl resin) were fabricated over identical self-cured resin dies and were divided into six groups (N= 72; 6 ×n= 12) of cement application techniques (Temp Bond NE, Kerr Corporation). Group-A (Bulk Fill); Group-B (Cement on inner walls); Group-C (Cement on axial walls); Group-D (Cement on crown margin); Group-E (Cement on tooth margin); Group-F (Cement with vent-holes). Adaptation was assessed before and after cementation with digital caliper (0.001mm). Universal testing machine was used for retention measurement in Mega Pascal's (MPa). Data was analyzed by SPSS using Paired T-Test and Tukey's test (p< 0.05). The highest and lowest difference between the two measurements was observed for the Group A (0.095mm) and Group C (0.030mm) respectively. Paired T-Test revealed significance (p< 0.05) between before and after cementation. Group-F (0.6094MPa) and Group-E (0.1858MPa) showed the highest and lowest retention respectively. Group-E (Cement on tooth margin) with lowest retention significantly differed (Tukey's Test; p< 0.05) from other groups. Bulk filling of the provisional crown with luting cement significantly increases the adaptation discrepancies. Discrepancies are more when luting cement is applied on the occlusal surface of the crowns. However, it didn't influence the retention of the crowns. Cement application on axial walls and cervical third of intaglio surface of crowns was the method of choice with regards to adaptation and retention combined. Addition of vent-holes improved the adaptation with best possible retention.

Does Tourniquet Use in TKA Increase Postoperative Pain? A Systematic Review and Meta-analysis.

Although tourniquets are commonly used during TKA, that practice has long been surrounded by controversy. Quantifying the case for or against tourniquet use in TKA, in terms of patient-reported outcomes such as postoperative pain, is a priority. The purpose of this study was to meta-analyze the available randomized trials on tourniquet use during TKA to determine whether use of a tourniquet during TKA (either for the entire procedure or some portion of it) is associated with (1) increased postoperative pain; (2) decreased ROM; and (3) longer lengths of hospital stay (LOS) compared with TKAs performed without a tourniquet. We completed a systematic review and meta-analysis using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines to assess the impact of tourniquet use on patients after TKA. We searched the following databases from inception to February 1, 2015, for randomized controlled trials meeting prespecified inclusion criteria: PubMed, Embase, and Cochrane Central Register of Controlled Trials. Postoperative pain was the primary outcome. Secondary outcomes were postoperative ROM and LOS. The initial search yielded 218 studies, of which 14 met the inclusion criteria. For our primary analysis on pain and ROM, a total of eight studies (221 patients in the tourniquet group, 219 patients in the no-tourniquet group) were meta-analyzed. We also performed a subgroup meta-analysis on two studies that used the tourniquet only for a portion of the procedure (from osteotomy until the leg was wrapped with bandages) and defined this as half-course tourniquet use (n = 62 in this analysis). The Jadad scale was used to ascertain methodological quality, which ranged from 3 to 5 with a maximum possible score of 5. Statistical heterogeneity was tested with I and chi-square tests. A fixed-effects (inverse variance) model was used when the effects were homogenous, which was only the case for postoperative pain; the other endpoints had moderate or high levels of heterogeneity. Publication bias was assessed using a funnel plot, and postoperative pain showed no evidence of publication bias, but the endpoint of LOS may have suffered from publication bias or poor methodological quality. We defined the minimum clinically important difference (MCID) in pain as 20 mm on the 100-mm visual analog scale (VAS). We found no clinically important difference in mean pain scores between patients treated with a tourniquet and those treated without one (5.23 ± 1.94 cm versus 3.78 ± 1.61 cm; standardized [STD] mean difference 0.88 cm; 95% confidence interval [CI], 0.54-1.23; p < 0.001). None of the studies met the MCID of 20 mm in VAS pain scores. There was also no clinically important difference in ROM based on degrees of flexion between the two groups (49 ± 21 versus 56 ± 22; STD mean difference 0.8; 95% CI, 0.4-1.1; p < 0.001). Similarly, we found no difference in mean LOS between groups (5.8 ± 4.4 versus 5.9 ± 4.6; STD mean difference -0.2; 95% CI, -0.4 to 0.1; p = 0.25). A subgroup meta-analysis also showed no clinically important difference in pain between the full-course and half-course tourniquet groups (5.17 ± 0.98 cm versus 4.09 ± 1.08 cm; STD mean difference 1.31 cm; 95% CI, -0.16 to 2.78; p = 0.08). We found no clinically important differences in pain or ROM between patients treated with and without tourniquets during TKA and no differences between the groups in terms of LOS. In the absence of short-term benefits of avoiding tourniquets, long-term harms must be considered; it is possible that use of a tourniquet improves a surgeon's visualization of the operative field and the quality of the cement technique, either of which may improve the long-term survivorship or patient function, but those endpoints could not be assessed here. We recommend that the randomized trials discussed in this meta-analysis follow patients from the original series to determine if there might be any long-term differences in pain or ROM after tourniquet use. Level I, therapeutic study.

Underhang of the tibial component increases tibial bone resorption after total knee arthroplasty.

One of the causes of aseptic loosening is marked tibial bone resorption (TR) at the tibial bone-component interface after total knee arthroplasty (TKA). It was hypothesized that insufficient coverage of the tibial component and improper cementing technique would cause increased TR after cemented TKA. One hundred thirty-four primary TKAs in 107 patients with varus osteoarthritis were included in this study. The relationships between the TRs at 2years after TKA and the tibial component underhang (TUH), the thickness of the cement mantle around the keel, and clinical parameters were evaluated. The widths of TRs on anteroposterior radiographs were significantly larger on the medial side than on the lateral side (p = 0.001), whereas the difference between the anterior and posterior sides on lateral radiographs was relatively small. Multiple regression analyses showed that medial TR was positively related to medial TUH (p = 0.006), and lateral TR was positively related to a thicker distal cement mantle (p = 0.027). On the lateral view, stepwise selection indicated that postoperative knee flexion angle was the most significant risk factor (p = 0.005) for anterior TR, and posterior TUH was the strongest predictor (p = 0.001) of posterior TR. To avert postoperative progressive TR, surgeons should perfectly fit a suitably sized tibial component to the medial edge of the tibia. Also, care should be taken to avoid an excessive cement mantle at the distal portion of the keel during TKA. IV.

Effect of Zr content on the structure and oxidation resistance of silicide coatings prepared by pack cementation technique

Modified silicide coatings were prepared on Ti-5Al-10Nb-xZr (x = 0, 2, 5, 10, 15 and 20 at.%) alloys by pack cementation process. The effects of Zr content on the coating structure and oxidation resistance have been investigated. With increasing Zr contents in the substrate, the coating structure shows a significant change. Adding 2 at.% Zr can improve the oxidation resistance of silicide coating due to the formation of a thin and dense SiO2 layer. But excessive Zr exerts an adverse influence on the oxidation resistance due to the volume expansion caused by the phase transformation of ZrO2 during the oxidation process.

Fourteen-year experience with short cemented stems in total hip replacement.

The age of the population requiring total hip replacement (THR) is increasing and this may lead to a return of cemented stems. Advantages of a short cemented femoral device include preservation of metaphyseal bone, easier insertion, and easier cement removal in case of revision. The purpose of this study is to describe the rationale and assess midterm results of unique innovative short cemented double-tapered polished stem applied with contemporary cementing techniques. Our experience with this short cemented stem includes two different groups of elderly patients. Group 1 (prototype version of the short stem) from January 2005 to January 2008 counts 43 THR. Group 2 (final commercial version of the short stem) from January 2013 to January 2015 counts 54 THR. The average age in groups 1 and 2 was 79 and 75 respectively. Patients underwent clinical follow-up with the Harris Hip Score (HHS) and completed radiographic evaluation. Thirty-one patients of group 1 had died for reasons unrelated to their THR. The surviving 9 hips have a follow-up of 11.2years. In group 2, eight patients died for reasons unrelated to their THR. Follow-up for the surviving 40 patients is 4.6years. HHS improved in both groups. In 34/43 hips of group 1 and in 41/54 of group 2 we observed a Barrack grade A cement mantle. Survival with revision of the stem for aseptic loosening as the endpoint was 100%. This study confirms the effectiveness of a short, polished, collarless, tapered cemented stem implanted with contemporary cementing techniques which appears as successful as the standard sized components.

Value comparison of humeral component press-fit and cemented techniques in reverse shoulder arthroplasty

Press-fit humeral fixation for reverse shoulder arthroplasty (RSA) has been shown to have loosening rates and outcomes similar to a cemented technique; however, increased value has not been reported. The purpose of this study was to determine whether the press-fit technique could improve the value of RSA using the procedure value index (PVI). Primary RSA patients with complete hospitalization cost data, preoperative and minimum 2-year postoperative Simple Shoulder Test (SST) scores, and postoperative satisfaction were included. The PVI was calculated as improvement in the SST score (in units of minimal clinically important difference) divided by total cost and normalized. Itemized cost data were obtained from hospital financial records and categorized. Radiographic complications, infections, and revisions were noted. Comparisons were made between the press-fit and cemented RSA cohorts. A total of 176 primary RSA patients (83 cemented and 93 press fit) met the inclusion criteria (mean follow-up period, 44.6 months). Surgical indications (except failed rotator cuff repair), baseline SST scores, and demographic characteristics were similar. The calculated minimal clinically important difference for the SST score was 3.98. The average PVI was significantly greater in the press-fit cohort (1.51 vs 1.03, P < .001), representing a 47% difference. SST score improvement was not significantly different (P = .23). However, total hospitalization costs were significantly lower for the press-fit cohort ($10,048.89 vs $13,601.14; P < .001). Use of a press-fit technique led to a 47% increase in value over a cemented technique. This appeared to be a function of decreased total costs rather than increased outcome scores.

High temperature oxidation resistance of γ-TiAl alloy with pack aluminizing and electrodeposited SiO2 composite coating

A novel Si-Al composite coating was prepared on γ-TiAl alloy by a two-step method. Firstly, an aluminizing coating was fabricated on γ-TiAl alloy via pack cementation technique. Then a SiO2 coating was prepared on this aluminizing coating via cathodic electrodeposition. The high temperature oxidation resistance of this composite coating was evaluated under 1000 °C. During the oxidation process, this Si-Al composite coating can react with TiAl and prevent the inward diffusion of oxygen from air to the film/alloy interface, resulting in the remarkable decreased oxidation rate of the alloy.

A new technique for the cementation of implant supported‐fixed restorations

A new technique for the cementation of implant supported‐fixed restorations

Improved biomechanics of two alternative kyphoplasty cementation methods limit vertebral recollapse.

The clinical efficacy of vertebral cement augmentation for compression fractures (VCFs) remains undetermined. Recent studies have shown that refracture and progression of deformity may occur after augmentation with significant clinical consequences. Vertebral body height loss following kyphoplasty has also been observed with cyclic loading. We hypothesized that height loss is partly due to lack of cement fill past the margin of cancellous bone created by balloon expansion with subsequent failure under load. The biomechanical characteristics of two alternative cementation techniques were compared to standard kyphoplasty in cyclically loaded cadaveric VCF constructs. Sectioned osteoporotic thoracolumbar cadaveric spines were compressed to 75% of anterior vertebral height. Specimens were then allocated to standard kyphoplasty, balloon pressurization (BP), with reinflation of the balloon after 50% cement injection, or endplate post (EP), with perforation of the cavity rim using an articulating curette prior to injection. Following cementation, each specimen was preconditioned and loaded over 100,000 cycles. All techniques improved vertebral height (p's < 0.005). The EP and BP techniques provided greater cement fill than the standard technique (p's ≤ 0.01). Normalized vertebral height loss following 100,000 cycles was reduced with the EP technique versus standard kyphoplasty (p < 0.04). Height loss was inversely correlated with cement fill (p < 0.03). No vertebral recollapse occurred with the EP technique in blinded radiographic analysis. Statement of clinical significance: The EP technique demonstrated improved biomechanical characteristics versus the standard technique in cadaveric osteoporotic VCF constructs with decreased recollapse following cementation. This technique may have increased efficacy in cases when kyphoplasty more substantially improves vertebral body height. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3225-3230, 2018.