Cementation Technique Research Articles

Effect of porcelain firing and cementation on the marginal fit of implant-supported metal-ceramic restorations fabricated by additive or subtractive manufacturing methods

Statement of problemAdaptation between abutment and suprastructure plays a crucial role in the long-term success of implant-supported metal-ceramic crowns. Fabrication methods, the porcelain firing stage, and cementation techniques may affect the marginal adaptation between the crown and abutment. However, the information regarding this issue is sparse. PurposeThe purpose of this in vitro study was to compare marginal fit after the fabrication of cobalt-chromium alloy copings, porcelain firing, and cementation of metal-ceramic restorations that were fabricated with computer-aided design and computer-aided manufacturing (CAD-CAM) milling and direct metal laser sintering techniques. Material and methodsThirty straight tissue-level titanium abutments were screwed onto implant analogs. All specimens were embedded in acrylic resin and divided into 2 groups according to CAD-CAM milling and direct metal laser sintering fabrication of the metal coping. Fifteen cobalt-chromium implant-supported metal copings were fabricated by using the CAD-CAM milling technique and 15 by using the direct metal laser sintering technique. In both groups, marginal gap measurements between the cobalt-chromium copings and abutments were obtained before (T0) and after the placement of the ceramic veneer (T1) and after cementation (T2) by using a stereomicroscope with a magnification of ×40. The data were statistically evaluated by using 2-way ANOVA and the Tukey post hoc test (α=.05). A t test was used to determine whether there were significant differences between the fabrication techniques (α=.05). ResultsA significant difference in the fabrication stages was found in the direct metal laser sintering group. The direct metal laser sintering coping group and porcelain applied direct metal laser sintering group had a statistically lower marginal gap value than the cemented direct metal laser sintering group (P=.021, P=.038). The direct metal laser sintering coping group had a lower marginal gap value than the CAD-CAM milling coping group, although the difference was not statistically significant (P=.216). ConclusionsPorcelain firing and cementation increased the marginal gap between the crown and abutment. No statistically significant differences were found between the direct metal laser sintering and CAD-CAM milling techniques in terms of marginal fit.

Glass fiber posts

Aim: Glass fiber posts are indicated in the rehabilitation of extensively damaged teeth; their cementation represents a critical step in restorative dentistry. The aim of this study was to quantify and compare the push-out bond strength of glass fiber posts cemented by conventional technique, two-step technique with luting agent and two-step technique associating bulk-fill composite and luting agent. Methods: Eighty maxillary bovine incisors were endodontically treated and divided into eight groups (n = 10) according to the luting agent (Rely X ARC and Duo-link) and cementation technique (conventional technique; two-step technique with luting agent; and two-step technique associating bulk-fill composite – Filtek Bulk-fill flow or Surefil SDR flow – and luting agent). Samples were submitted to pushout bond strength test, and the fracture pattern was evaluated through scanning electron microscope. Data were submitted to two-way ANOVA and Tukey’s test (α = 0.05). Results: When Rely X ARC was used, the conventional cementation technique obtained higher bond strength values than the twostep technique associated with Filtek Bulk-fill flow. When Duolink was used, the two-step technique associated with Filtek Bulk-fill flow presented higher bond strength values than the conventional technique. The most prevalent fracture patterns were adhesive between luting agent and dentin, and adhesive between bulk-fill composite and dentin. Conclusion: Two-step cementation technique associated with bulk-fill composite may be promising depending on the luting agent used.

Classifications in Brief: The Dorr Classification of Femoral Bone.

Classifications in Brief: The Dorr Classification of Femoral Bone.

Fracture Resistance of Zirconia-Reinforced Lithium Silicate Ceramic Crowns Cemented with Conventional or Adhesive Systems: An In Vitro Study.

In recent years, Zirconia-reinforced Lithium Silicate ceramic (ZLS), combining lithium-silicate and zirconia features, has shown to have excellent mechanical and aesthetic characteristics. Thus, the aim of this study was to compare the fracture strength of ZLS single crowns cemented with two different cementation techniques. Twenty crowns were realised and cemented on teeth replicas achieved from an extracted premolar human tooth. The samples were divided into two groups of 10 specimens each, Glass-ionomeric cement (GIC) group and Self-Adhesive Resin Cement (ARC) group. The mechanical test was performed using a universal testing machine. The specimens were then evaluated with a scanning electron microscope (SEM) to identify for all crowns and related abutments the pattern of fracture after the breaking point. The data obtained were statistically analysed. The mean fracture toughness values and standard deviations (±SD) were 2227 ± 382 N and 3712 ± 319 N respectively for GIC and ARC groups. In fact, t-test showed a statistically significant difference between the two groups (p < 0.001). Moreover, the SEM results demonstrated portions of abutments still attached to the crown fragments in the ARC group, whilst these were not present in the GIC group. Within the limitations of this study, these results suggest the use of adhesive cementation for ZLS crowns, which significantly increase the compressive strength of ZLS restorations compared to GIC.

Radiographic, Functional, and Oncologic Outcomes of Cemented Modular Proximal Femur Replacement Using the “French Paradox” Technique

BackgroundEndoprostheses are frequently used in the management of tumors involving the proximal femur. Aseptic loosening is a common complication that has been linked to the cementing technique. The “French paradox” is well-known cementing technique in the arthroplasty literature. No previous reports have assessed loosening in proximal femur replacements using this technique. We examined rates of femoral stem aseptic loosening in proximal femur replacements, functional outcomes, complications, and oncologic outcomes. MethodsWe conducted a retrospective review of 47 patients who underwent proximal femur replacement between 2000 and 2019. Two reviewers evaluated preoperative and postoperative radiographs using the International Society of Limb Salvage scoring system and Barrack criteria for stem loosening. The acetabulum was evaluated according to the criteria of Baker et al. Functional outcomes were assessed using Musculoskeletal Tumor Society (MSTS) score and Toronto Extremity Salvage Score. The mean follow-up was 44 months. ResultsThe mean International Society of Limb Salvage scores for the 2 reviewers were 86% ± 6% and 84% ± 6%. The first reviewer graded femoral stem loosening as “possibly loose” in 2 patients, one of whom was graded as possibly loose by the second reviewer. The 2 reviewers found no acetabular erosion in 16 (70%) and 15 (65.4%) patients, respectively. The mean Musculoskeletal Tumor Society score and Toronto Extremity Salvage Score at last follow-up were 61% and 72%, respectively. Twenty complications occurred in 13 patients, and 5 patients experienced local recurrence. ConclusionDespite complications, we showed favorable femoral component survival rates. Cementing the proximal femur prosthesis with tight canal fit and thin cement mantle is a viable option for the short and medium term. Level of EvidenceIII.

Recovery of Lead and Zinc from Zinc Plant Leach Residues by Concurrent Dissolution-Cementation Using Zero-Valent Aluminum in Chloride Medium

Zinc plant leach residues (ZPLRs) contain significant amounts of metal compounds of lead (Pb), zinc (Zn), iron (Fe), etc., hence, they are considered as a secondary source of metals. On the other hand, ZPLRs are regarded as hazardous materials because they contain heavy metals that pollute the environment. Resources and environmental concerns of ZPLRs were addressed in this study by removing/recovering Pb and Zn using a concurrent dissolution and cementation technique. To cement the dissolved Pb and Zn in leaching pulp, zero-valent aluminum (ZVAl) was added during ZPLRs leaching in the hydrochloric (HCl)–sodium chloride (NaCl) solution. The resulting cemented metals were agglomerated and separated by sieving. Lead removal increased with increasing both NaCl and HCl concentrations. However, when ZVAl was added, significant Pb removal was achieved at a low concentration. Zinc was not cemented out of the pulp using ZVAl and its recovery from ZPLRs was dependent on the HCl concentration only. By applying a concurrent dissolution and cementation technique, both Pb and Zn were removed using a low concentration of NaCl, and most importantly Pb—the most toxic metal in ZPLRs—was captured and separated before the solid-liquid separation, hence, eliminating the need for extensive washing of the generated residues to remove the inherent residual solution.

Current concepts and outcomes in cemented femoral stem design and cementation techniques: the argument for a new classification system.

Cemented implant fixation design principles have evolved since the 1950s, and various femoral stem designs are currently in use to provide a stable construct between the implant–cement and cement–bone interfaces.Cemented stems have classically been classified into two broad categories: taper slip or force closed, and composite beams or shaped closed designs. While these simplifications are acceptable general categories, there are other important surgical details that need to be taken into consideration such as different broaching techniques, cementing techniques and mantle thickness.With the evolution of cemented implants, the introduction of newer implants which have hybrid properties, and the use of different broaching techniques, the classification of a very heterogenous group of implants into simple binary categories becomes increasingly difficult. A more comprehensive classification system would aid in comparison of results and better understanding of the implants’ biomechanics.We review these differing stem designs, their respective cementing techniques and geometries. We then propose a simple four-part classification system and summarize the long-term outcomes and international registry data for each respective type of cemented prosthesis.Cite this article: EFORT Open Rev 2020;5:241-252. DOI: 10.1302/2058-5241.5.190034

Masquelet technique for treatment of post-traumatic bone defects

Background: Segmental bone defects from traumatic injuries are complicated problems with significant long term morbidity. Historically, amputation was the preferred treatment although, limb salvage by Ilizarov technique, vascularized fibular graft, and acute limb shortening were also used. The treatment regimes were long, burdensome and patient unfriendly involving multiple procedures and complications. Masquelet described the technique of antibiotic cement spacer following debridement for an induced bio-membrane, with subsequent bone- grafting within this space. However, similar results were not reported at multiple centers due to damage to the biomembrane while removal of the cement. Hence, the present study describes the technique of cementation and cement retrieval in order to prevent the damage of the bio-membrane. Objective: To study the outcome of the role of Masquelet technique in the management of post-traumatic (long) bone defects following trauma presenting at our center.Method: 15 patients with mean bone defect of 7.2 cm after debridement were operated with the modified Masquelet technique.Results: Union was obtained in all of the cases; the average time for bony union was 8 months since first presentation with mean follow up of 2.5 years. Conclusion: The technique of delayed bone grafting with definitive fixation after initial debridement and placement of a cement spacer provides excellent results for patients with large posttraumatic bone segment loss.

Aluminide and silicide diffusion coatings by pack cementation for Nb-Ti-Al alloy

Halide activated pack cementation technique was successfully used to elaborate protective coatings, based on silicon- or aluminum-rich intermetallic compounds, for a Nb-Ti-Al alloy. Thermodynamic computations showed that growth mechanism of coating involves different chemical reactions. The substrate shows a poor behavior in thermal oxidation with the formation of non-protective oxides and high solubility of oxygen in its microstructure. The effectiveness of the deposited MAl3 and MSi2 coatings to protect the substrate was demonstrated. Reliability and high oxidation resistance of these diffusion coatings are promoted by their good adherence to the substrate, capability to accommodate thermo-mechanical stress and ability to form adherent and compact Al2O3 and SiO2 oxide scales. These oxide scales grow during the oxidation process at 900 and 1000 °C according to very low kinetics as demonstrated by the curves of mass change versus time. The mass changes of the coated substrate with aluminide and silicide were <1.5 mg·cm−2 after 650 h of exposure at 1000 °C.

Clinical Evaluation of Chairside-Fabricated Partial Crowns Made of Zirconia- Reinforced Lithium Silicate Ceramic - 2-Year-Results.

In a prospective study, the clinical performance of chairside-fabricated partial-crowns made of zirconia-reinforced lithiumsilicate (ZLS)-ceramic was evaluated after 2 years. 45 patients (28 female/17 male) underwent restoration with 61 chairside-fabricated ZLS partial-crowns on vital premolars and molars. In variation from the manufacturer's recommendations (minimum material thickness (MMT)=1.0 mm), partial-crowns with reduced material thicknesses were fabricated: group 1, MMT=0.5-0.74 mm (n=31); group 2, MMT=0.75-1.0 mm (n=30). The restorations were luted with either a self-adhesive cement (SAC) or the total-etch technique using a dual-curing composite cement (DC). The MMT and cementation technique (SAC vs. DC) were evaluated as possible covariates of the time-dependent survival (SVR) and success rate (SCR) using univariate log-rank-tests. Forty-four patients with 59 restorations participated in the 2-year follow-up examinations. In group 1 (n=31), there were 2 losses due to ceramic fracture (SVR: 94.0% (95% confidence interval (CI): 0.85-1)). In group 2, no losses were documented (SVR: 100%). In 2 restorations cemented with SAC, recementation was necessary (overall SCR: 93% (CI: 0.87-1)). To avoid early material-related fractures, observing the recommended minimum thickness of 1.0 mm is essential. However, further validation of these results in studies with longer observational periods is required.

Aseptic Loosening at the Tibia in Total Knee Arthroplasty: A Function of Cement Mantle Quality?

BackgroundAseptic loosening remains one of the leading causes for failure of total knee arthroplasty (TKA). We sought to identify early radiographic measures that may associate with aseptic tibial component loosening, emphasizing systematic evaluation of the cement mantle. MethodsAll TKA revisions from 2007 to 2015 with the primary indication of tibial aseptic loosening were identified using in an institutional implant retrieval database. After exclusion criteria, 61 TKAs comprised the study group. A matched control group of 59 TKAs that had not failed at a minimum of 3 years was identified for comparison. Radiographic analysis on all 6-week postoperative radiographs included angulation of components, cement penetration depth, and presence of radiolucency at the implant-cement and bone-cement interfaces. Groups were compared with Student’s t-test, chi-squared test, and Mann-Whitney U-test. A final multivariable logistic regression model was formed for the outcome of aseptic loosening. ResultsOn multivariable analysis, failure was associated with a greater number of zones with cement penetration <2 mm (5.6 vs 3.4 zones, odds ratio [OR] 1.89, P < .001), increasing percent involvement of radiolucency at the implant-cement interface (8.7% vs 3.1%, OR = 1.15, P = .001), and increased varus alignment of the tibial component (1.5° vs 0°, OR = 1.35, P = .014). A greater number of zones with a radiolucent line at the bone-cement interface did not significantly associate (1.1 vs 0.3, P = .091). ConclusionOur results suggest that radiographic indicators of poor cement mantle quality associate with later aseptic loosening. This emphasizes the need for surgeons to perform careful cement technique in order to reduce the risk of TKA failure. Level of EvidenceIII (Case-control).

The Use of Cement in Hip Arthroplasty: A Contemporary Perspective.

Notable advances in hip arthroplasty implants and techniques over the past 60 years have yielded excellent survivorship of fully cemented, hybrid, and reverse hybrid total hip replacements as demonstrated in joint registries worldwide. Major advances in noncemented implants have reduced the use of cement, particularly in North America. Noncemented implants predominate today based on procedural efficiency, concern related to thromboembolic risk, and a historic belief that cement was the primary cause of osteolysis and implant loosening. With the decline of cemented techniques, press-fit fixation has become common even in osteoporotic elderly patients. Unfortunately, there is a troubling rise in intraoperative, as well as early and late postoperative periprosthetic fractures associated with the use of noncemented implants. Despite the success of noncemented fixation, an understanding of modern cement techniques and cemented implant designs is useful to mitigate the risk of periprosthetic fractures. Cemented acetabular components can be considered in elderly patients with osteoporotic or pathologic bone. Cemented stems should be considered with abnormal proximal femoral morphology, conversion of failed hip fixation, inflammatory arthritis, patient age over 75 (especially women), osteoporotic bone (Dorr C), and in the treatment of femoral neck fractures.

Analysis of high plasticity clayey soil improvement at subgrade level through Portland cement added to decrease volumetric change

This research includes the potential for resistance and the expansion that the soil presents, this evaluation was carried out through CBR tests. The soil cement technique was used to improve the physical and mechanical characteristics; this process consists in mixing the material with Portland cement type I. That combination forms soil cement 10%, 15% y 20%, which present an increase of the CBR (max: 138.7% and min: 91.9%) achieving a type of extraordinary subgrade to resist the structure of the pavement and a reduction of 7.18% in the expansion of the samples.

An in vitro investigation comparing methods of minimizing excess luting agent for cement-retained implant-supported fixed partial dentures

Statement of problemThe use of cement-retained implant-supported prostheses is a well-established treatment option. Techniques have been proposed to reduce the amount of residual excess cement (REC) around cement-retained single-implant restorations. However, studies evaluating the effectiveness of such techniques related to cement-retained implant-supported fixed partial dentures (CRISFPDs) are lacking. PurposeThe purpose of this in vitro study was to evaluate the effectiveness of various cement application techniques for CRISFPDs. Material and methodsTwo implant analogs were placed in the lateral incisor sites in a maxillary, 3D printed cast with 4 missing incisors. Twenty standardized, removable, printed soft-tissue replicas, 40 milled titanium custom abutments, and 20 milled zirconia CRISFPDs were fabricated. Two cement application techniques, the brush on technique (BOT), and the polyvinyl siloxane index (PI) technique were compared. Two cementation techniques, without bib (control) (n=10) and with a polytetrafluoroethylene (PTFE) bib (test) (n=10), were used. A premeasured amount of interim cement was used to cement the CRISFPDs. The CRISFPDs were retrieved after cementation, and standardized photographs of 4 quadrants of each abutment-CRISFPD assembly were made by using a software program that is used to calculate the ratio between the area covered with REC and the total specimen area. The extension of the REC on both the abutment and soft-tissue replica was measured at sites before and after cleaning the REC. A generalized linear mixed-model procedure was used for statistical analysis (α=.05). ResultsFor cement application, the polyvinyl siloxane (PVS) index technique had significantly less REC than the brush on technique (P<.05). The use of a PTFE bib led to significantly less REC than when no bib was used (P<.05). ConclusionsThe use of the PVS index technique along with a PTFE bib was effective in reducing REC for CRISFPDs.

Fracture of the Femoral Component in TKR – A Case Report

Femoral component fracture in total knee replacement (TKR) is a rare complication. In the majority of case reports, stress fractures of the femoral component have predominantly affected the medial condyle, following uncemented implantation of fixed-bearing knees. We report the case of fracture of the lateral condyle of a cemented fixed TKR due to bad cementing technique.

Aluminization of a Si–Y co-deposition coating to protect a Ti2AlNb based alloy from high temperature oxidation

Coatings were prepared by aluminization of a Si–Y co-deposition coating on a Ti2AlNb based alloy using halide activated pack cementation technique. The microstructure evolution and the high temperature oxidation behavior of the coatings were investigated. During the aluminization, the (Ti,Nb)5Si4 inner layer of the Si–Y co-deposition coating was consumed faster than the (Nb,Ti)Si2 outer layer. A (Ti,Nb)Al3 superficial layer and a (Nb,Ti)3Si5Al2 + (Ti,Nb)Al3 middle layer successively formed. Besides, (Nb,Ti)3Si5Al2 pieces appeared inside the outer layer when solid solution Al in (Nb,Ti)Si2 reached saturation. Both inward diffusion of active [Al] atoms and outward diffusion of Ti and Nb atoms controlled the coating growth. The outward diffusion of Ti and Nb atoms caused Al beneath the inner layer was enriched continuously. The Si–Y co-deposition + aluminization coating could provide better protection for the Ti2AlNb based alloy from oxidation at 1123 K than the Si–Y co-deposition coating, which was attributed to preferential formation of Al2O3 on the surface to prohibit formation of loose TiO2. After the oxidation for 100 h, a continuous, compact and adhesive oxide scale consisting of an Al2O3 main part and an Al2O3 + TiO2 + SiO2 lower part formed on the coating.

Mechanism exploration on the aluminum supplementation coupling the electrokinetics-activating geopolymerization that reinforces the solidification of the municipal solid waste incineration fly ashes

Traditional cementation technique is insufficient in making municipal solid waste incineration (MSWI) fly ashes meet the permissible leaching threshold. Aluminum supplementation and electrokinetic (EK) activation were combinedly incorporated into the traditional solidification pathway to enhance the geopolymerization and the immobilization of Pb and Cd in MSWI fly ashes in this study. The aluminum addition remarkably affected the geopolymer formation. The minimum toxicity leaching as well as the maximum compressive strength were achieved at the combination of the voltage gradient of 1.0 V/cm, the proposing time of 48 or 72 h, the mass ratio of alkali activator to fly ash of 11.5%, and the modulus of 2.1. Chloride reduction in the mortar obtained during the EK process increased the negative charge relativity of oligomers. The leaching concentrations of Pb and Cd from the geopolymer were successfully predicted by a linear model based on the compressive strengths at 28 d. Higher reaction degree was found in the EK-activated mortar in the geopolymerization kinetics. Aluminum supplementation had induced the production of some amorphous aluminosilicate minerals including Al6Si2O13, CaAl2Si2O8·4H2O, Ca2Al3(Si3O12)OH, Ca2Al(OH)7·3H2O, and Ca4Al2O6Cl2·10H2O during the EK process. Larger particles observed in the EK-treated specimen directly verified the EK-activated pozzolanic reactions.

Assessment of Marginal Opening for Different Cementation Techniques for Heat-Pressed Ceramic Veneers.

The aim of this study is to evaluate the gap distance of two cementation techniques for laminate veneers fabricated on maxillary anterior teeth using heat-pressed ceramic, finger pressure, and ultrasonic cementation techniques. A total number of 42 extracted natural central incisors were prepared to receive ceramic laminate veneers, laminate veneers were constructed in the laboratory using heat-pressed ceramic according to manufacturer's instructions (IPS e.max). Ceramic veneers were divided into two groups and cemented using two different cementation techniques (Ultrasonic, finger pressure). Marginal gap distance was measured in microns at the margins using a stereomicroscope and special computer software (quantitative assessment). The ultrasonic cementation technique recorded 63.3 ± 27.8 μm, which was significantly lower than the finger pressure technique (91.5 ± 21.4 μm). The ultrasonic cementation technique improved the gap distance at the tooth/ceramic interface when compared to the finger pressure technique using the light cure cement.

Effect of Cement Type and Cementation Technique on the Retention of Implant-Supported Restorations.

This study aimed to assess the effect of cement type and cementation technique on the retention of cement-retained implant-supported restorations. In this in vitro study, 20 solid abutments were screwed onto the fixture analogs and were mounted in acrylic resin molds using a surveyor. Twenty computer-aided design/computer-aided manufacturing (CAD/CAM) metal crowns with an occlusal loop were fabricated, divided into two groups (n = 10), and bonded with temporary dental cement (Temp-Bond™; group 1) or glass ionomer (GC; group 2). Each group was subcategorized based on its cementation method (half-filling or abutment replica technique). The cement was applied to the copings that were placed vertically on the abutment with applying a 5-kg load for 10 min. The samples were then incubated at 37°C for 24 h and subjected to 3000 thermal cycles. The samples underwent axial tensile load within a universal testing machine. Data were analyzed using two-way ANOVA. GC cement yielded significantly higher retention than Temp-Bond™ (P < 0.05). In the GC group, the half-filling subgroup showed significantly higher retention than the abutment replica subgroup (P < 0.05). The mean retention value in the Temp-Bond™ group revealed no significant difference between the two subgroups (P > 0.05). GC yielded higher retention than Temp-Bond™ while using the half-filling cementation technique (P = 0.00). However, this difference was not significant between GC and Temp-Bond™ with the abutment replica technique (P = 0.960). Within the limitations of this study, the results showed that permanent cementation with half-filling technique yielded significantly higher retention in implant restorations.

A case of ceramic bipolar hip arthroplasty using cementing technique in patient with severe metal allergy

A case of ceramic bipolar hip arthroplasty using cementing technique in patient with severe metal allergy