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Badrian, Hamid, Mahmoud Sabouhi, Saeid Nosouhian, Amin Davoudi, Farzaneh Nourbakhshian, and Fatemeh Naderi Nabe. "The Effect of Eugenol-Free Temporary Cement's Remnants on Retention of Full Metal Crowns: Comparative Study." Journal of Contemporary Dental Practice 14, no. 3 (2013): 473–77. http://dx.doi.org/10.5005/jp-journals-10024-1347.
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ABSTRACT Introduction The aim of this study was to evaluate the effects of eugenol-free temporary cement's remnants on the retentive strength of full metal crowns luted via zinc phosphate and resin cement (Maxcem) to the tooth structure. Materials and methods Forty complete standardized Ni-Cr crowns in four groups were cemented by two types of permanent cements: zinc phosphate cement and resin cement (Maxcem). In the two groups before permanent cementation of crowns, temporary acrylic crowns were cemented by eugenol-free temporary cement. Crowns¡¦ retention was evaluated by Universal testing machine. All data were analyzed by means of one-way ANOVA test in SPSS software version 11.5 (α = 0.05). Results There was no significant difference in groups with prior using eugenol-free temporary cement and groups with just using two permanents cement (p-value ≥ 0.05). Discussion The application of temporary cement before permanent cementation of full metal crowns does not have any adverse effect on retention of full metal crowns, when temporary cements are removed properly. How to cite this article Sabouhi M, Nosouhian S, Davoudi A, Nourbakhshian F, Badrian H, Nabe FN. The Effect of Eugenol- Free Temporary Cement's Remnants on Retention of Full Metal Crowns: Comparative Study. J Contemp Dent Pract 2013; 14(3):473-477.
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Rego, Mariana Ribeiro de Moraes, and Luiz Carlos Santiago. "Retention of provisional crowns cemented with eight temporary cements: comparative study." Journal of Applied Oral Science 12, no. 3 (September 2004): 209–12. http://dx.doi.org/10.1590/s1678-77572004000300009.
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Many temporary cements are commercially available; therefore, it is necessary to indicate them for each clinical requirement with regard to the tensile strength of prosthetic retainers. Thus, the purpose of this study was to compare the retention of provisional crowns cemented with eight temporary cements, over full crown preparations with standardized mechanical principles as height, taper, and length. For that purpose, eighty human first premolars received full crown preparation with standardized height and taper. Provisional crowns were fabricated and luted with eight brands of temporary cements. Twenty four hours after cementation, the restorations were submitted to tensile strength test in a universal testing machine and the data submitted to ANOVA and Bonferroni tests. Mean tensile strength values ranged from 20.1N for Nogenol cement to 67.5N for Hydro C cement. Statistically significant difference (p<0.05) was found between Hydro C and the other groups, except for Temp Bond and Rely X Temp, which presented statistically significant difference when compared to Freegenol and Nogenol temporary cements. The crowns cemented with Hydro C cement were more retentive that than those cemented with the other cements, except for Rely X Temp and Temp Bond. The less retentive crowns were those cemented with Nogenol and Freegenol temporary cements.
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Bandéca, Matheus Coelho, Adriano Augusto Melo de Mendonça, Etevaldo Matos Maia Filho, Fausto da Silva Bramante, Darlon Martins Lima, Daniele Meira Conde, Vandilson Pinheiro Rodrigues, Soraia de Fátima Carvalho Souza, José Roberto Oliveira Bauer, and Suellen Nogueira Linares Lima. "Influence of Relining Post on the Bond Strength of Resin Cements." Journal of Contemporary Dental Practice 16, no. 7 (2015): 559–64. http://dx.doi.org/10.5005/jp-journals-10024-1722.
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ABSTRACT This study evaluated the influence of relining fiber posts on the bond strength (BS) of resin cements in the root canal. Forty bovine teeth were divided in four groups (n = 10)G1 (ARC)—fiber post cemented with resin cement RelyX ARC; G2 (ARC+Z350)—relined fiber post cemented with RelyX ARC; G3 (U200)—fiber post cemented with self-adhesive cement RelyX U200; G4 (U200+Z350)—relined fiber post cemented with RelyX U200. The roots were sectioned in six 1.2-mm slices and the push-out test was performed. Data were analyzed by three-way analysis of variance (ANOVA), and Tukey's test (α = 0.05). For the conventional resin cement, there was no significant difference between groups G1-ARC (15.5 ± 3.8) and G2-ARC+Z350 (16.1 ± 4.5). For the self-adhesive cement, the results revealed higher BS values for relined posts G4-U200 + Z350 (19.9 ± 7.9) as compared to non-relined posts G3-U200 (14.4 ± 4.5). For both cements, in groups of relined posts, the apical and the cervical thirds presented similar BS. Relining enhances the performance of the self-adhesive resin cement, and the interaction between relining and root third influences the BS to the conventional resin cement. How to cite this article Conde DM, Rodrigues VP, de Fátima Carvalho Souza S, Bauer JRO, da Silva Bramante F, Lima SNL, Filho EMM, Bandeca MC, de Mendonça AAM, Lima DM. Influence of Relining Post on the Bond Strength of Resin Cements. J Contemp Dent Pract 2015;16(7):559-564.
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Cantekin, Kenan, Ebru Delikan, and Secil Cetin. "In vitro bond strength and fatigue stress test evaluation of different adhesive cements used for fixed space maintainer cementation." European Journal of Dentistry 08, no. 03 (July 2014): 314–19. http://dx.doi.org/10.4103/1305-7456.137632.
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ABSTRACT Objective: The purposes of this research were to (1) compare the shear-peel bond strength (SPBS) of a band of a fixed space maintainer (SM) cemented with five different adhesive cements; and (2) compare the survival time of bands of SM with each cement type after simulating mechanical fatigue stress. Materials and Methods: Seventy-five teeth were used to assess retentive strength and another 50 teeth were used to assess the fatigue survival time. SPBS was determined with a universal testing machine. Fatigue testing was conducted in a ball mill device. Results: The mean survival time of bands cemented with R & D series Nova Glass-LC (6.2 h), Transbond Plus (6.7 h), and R & D series Nova Resin (6.8 h) was significantly longer than for bands cemented with Ketac-Cem (5.4 h) and GC Equia (5.2 h) (P < 0.05). Conclusion: Although traditional glass ionomer cement (GIC) cement presented higher retentive strength than resin-based cements (resin, resin modified GIC, and compomer cement), resin based cements, especially dual cure resin cement (nova resin cement) and compomer (Transbond Plus), can be expected to have lower failure rates for band cementation than GIC (Ketac-Cem) in the light of the results of the ball mill test.
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Marchan, Shivaughn, Larry Coldero, Robert Whiting, and Salvacion Barclay. "In vitro evaluation of the retention of zirconia-based ceramic posts luted with glass ionomer and resin cements." Brazilian Dental Journal 16, no. 3 (December 2005): 213–17. http://dx.doi.org/10.1590/s0103-64402005000300008.
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The retention of zirconia-based ceramic posts (CosmoPost system) luted with glass ionomer and resin cements was evaluated. Thirty-two extracted, caries-free, unrestored teeth were selected and stored in chlorhexidine and water solution. The teeth were endodontically treated and randomly assigned to two groups (n=16). Each tooth was decoronated and prepared to a depth of 10.0 mm from root surface to receive a 1.4 mm diameter zirconium dioxide post. Each group had posts cemented with either glass ionomer cement (Fuji I) or resin cement (Variolink II). The post/teeth specimens were embedded in resin blocks and subjected to tensile testing. The tensile force required to dislodge the cemented posts in a tensile testing machine was recorded. The mean stress values of both groups were analyzed for statistical differences using ANOVA and Student's t-test. Significance level was set at 5%. Mean peak forces at failure (N) and standard deviation for the tested cements were the following: Fuji I = 121.8 (±17.4) and Variolink II = 228.1 (±36.8). Posts luted with the resin cement presented statistically significant higher tensile bond strength than those retained with glass ionomer (p<0.05). It may be concluded that zirconia posts cemented with resin-based cement (Variolink II) failed at statistically significant higher values compared to those cemented with glass ionomer cement (Fuji I). Regardless of the cement type, the posts failed adhesively at the cement/post interface when subjected to a tensile force.
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Al-Wahadni, Ahed M., David L. Hussey, Nicholas Grey, and Muhanad M. Hatamleh. "Fracture Resistance of Aluminium Oxide and Lithium Disilicate-based Crowns using Different Luting Cements: An in vitro Study." Journal of Contemporary Dental Practice 10, no. 2 (2009): 51–58. http://dx.doi.org/10.5005/jcdp-10-2-51.
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Abstract Aim The aim of this study was to investigate the fracture resistance of two types of ceramic crowns cemented with two different cements. Methods and Materials Forty premolar crowns were fabricated using lithium-disilicate (IPS Empress-2) and glass-infiltrated aluminium-oxide (In-Ceram) ceramic systems. The crowns were divided into four groups (n=10) with Group 1 (IPS Empress-2) and Group 2 (In-Ceram) cemented with glass ionomer cement. Group 3 (IPS Empress-2) and Group 4 (In-Ceram) were cemented with resin cement. Crowns were tested in a universal testing machine at a compressive-load speed of 10 mm/min. Fracture modes were grouped into five categories. One way analysis of variance (ANOVA) and Bonferroni post-hoc tests were used to detect statistical significances (p<0.05). Results The mean (SD) fracture resistance (Newtons) for Groups 1 to 4 were: 245.35 (82.69), 390.48 (67.03), 269.69 (10.33), and 418.36 (26.24). The cement type had no statistical significant effect (p>0.05) on fracture resistance within each ceramic system tested. In-Ceram crowns cemented with either glass ionomer or resin cements exhibited a statistically significantly higher fracture-resistance than IPS Empress-2 crowns (p<0.05). Minimal fracture in the test crowns was the common mode exhibited. Conclusion Fracture resistance of IPS Empress-2 and In-Ceram crowns was not affected by the type of cement used for luting. Clinical Significance Both In-Ceram and IPS Empress-2 crowns can be successfully luted with the cements tested with In-Ceram exhibiting higher fracture resistance than IPS Empress-2. Citation Al-Wahadni AM, Hussey DL, Grey N, Hatamleh MM. Fracture Resistance of Aluminium Oxide and Lithium Disilicate-based Crowns using Different Luting Cements: An in vitro Study. J Contemp Dent Pract 2009 March; (10)2:051-058.
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Naumova, Ella, Felix Roth, Berit Geis, Christine Baulig, Wolfgang Arnold, and Andree Piwowarczyk. "Influence of Luting Materials on the Retention of Cemented Implant-Supported Crowns: An In Vitro Study." Materials 11, no. 10 (September 28, 2018): 1853. http://dx.doi.org/10.3390/ma11101853.
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The retention force of cemented crowns on implant abutments with various luting materials was evaluated. Cobalt–chromium crowns were cemented onto tapered titanium abutments (Camlog) with eugenol-free temporary cement (RelyX TempBond NE), composite-based temporary cement (Bifix Temp), zinc phosphate cement (Harvard Cement), glass-ionomer cements (Meron, Fuji I), and resin-modified glass-ionomer cements (Fuji II, Fuji Plus, Ketac Cem Plus). Specimen aging via hydrostress was performed in artificial saliva at 37 °C for 14 days (S1), followed by hydrothermal stress with thermocycling (S2). The crowns were removed, and the force was recorded (T1). Subsequently, the crowns were recemented, aged, and removed, and the force was recorded (T2, T3). The retention forces differences were statistically significant according to the storage conditions at T1 (p = 0.002) and T3 (p = 0.0002). After aging (S1), Ketac Cem Plus had the highest retention force median value difference (T3 versus T1) (−773 N), whereas RelyX TempBond NE had the lowest (−146 N). After aging (S2), Meron had the highest retention force median value difference (−783 N), whereas RelyX TempBond NE had the lowest (−168 N). Recementation decreased the retention force of the implant-supported cobalt–chromium crowns cemented and recemented with the same luting materials. Luting materials (at T1) and aging conditions significantly impacted the retention force.
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Orsi, Iara A., Fernando K. Varoli, Carlos H. P. Pieroni, Marly C. C. G. Ferreira, and Eduardo Borie. "In Vitro Tensile Strength of Luting Cements on Metallic Substrate." Brazilian Dental Journal 25, no. 2 (April 2014): 136–40. http://dx.doi.org/10.1590/0103-6440201302290.
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The aim of this study was to determine the tensile strength of crowns cemented on metallic substrate with four different types of luting agents. Twenty human maxillary molars with similar diameters were selected and prepared to receive metallic core castings (Cu-Al). After cementation and preparation the cores were measured and the area of crown's portion was calculated. The teeth were divided into four groups based on the luting agent used to cement the crowns: zinc phosphate cement; glass ionomer cement; resin cement Rely X; and resin cement Panavia F. The teeth with the crowns cemented were subjected to thermocycling and later to the tensile strength test using universal testing machine with a load cell of 200 kgf and a crosshead speed of 0.5 mm/min. The load required to dislodge the crowns was recorded and converted to MPa/mm2. Data were subjected to Kruskal-Wallis analysis with a significance level of 1%. Panavia F showed significantly higher retention in core casts (3.067 MPa/mm2), when compared with the other cements. Rely X showed a mean retention value of 1.877 MPa/mm2 and the zinc phosphate cement with 1.155 MPa/mm2. Glass ionomer cement (0.884 MPa/mm2) exhibited the lowest tensile strength value. Crowns cemented with Panavia F on cast metallic posts and cores presented higher tensile strength. The glass ionomer cement showed the lowest tensile strength among all the cements studied.
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Samy, Nourhan, Walid Al-Zordk, Ahmed Elsherbini, Mutlu Özcan, and Amal Abdelsamad Sakrana. "Does Resin Cement Type and Cement Preheating Influence the Marginal and Internal Fit of Lithium Disilicate Single Crowns?" Materials 15, no. 2 (January 6, 2022): 424. http://dx.doi.org/10.3390/ma15020424.
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This paper assesses the effect of cement type and cement preheating on the marginal and internal fit of lithium disilicate single crown. Methods: 40 maxillary premolars were selected, restored with lithium disilicate single crowns. Teeth were randomly assigned into four groups (n = 10) based on cement type (Panavia SA or LinkForce) and preheating temperature (25 °C or 54 °C). After fabrication of the restoration, cements were incubated at 25 °C or 54 °C for 24 h, and each crown was cemented to its corresponding tooth. After 24 h, all specimens were thermally aged to (10,000 thermal cycles between 5 °C and 55 °C), then load cycled for 240,000 cycles. Each specimen was then sectioned in bucco-palatal direction and inspected under a stereomicroscope at x45 magnification for marginal and internal fit evaluation. The data were statistically analyzed (significance at p ≤ 0.05 level). Results: At the mid-buccal finish line, mid-buccal wall, palatal cusp, mid-palatal wall, mid-palatal finish line, and palatal margin measuring points, there was a significant difference (p ≤ 0.05) between the lithium disilicate group cemented with Panavia SA at 25 °C and the group cemented with LinkForce at 25 °C, while there was no significant difference (p > 0.05) at the other points. At all measuring points, except at the palatal cusp tip (p = 0.948) and palatal margin (p = 0.103), there was a statistically significant difference (p ≤ 0.05) between the lithium disilicate group cemented with Panavia SA at 54 °C and the group cemented with LinkForce at 54 °C. Regardless of cement preheating, statistically significant differences were found in the buccal cusp tip, central groove, palatal cusp tip, and mid-palatal wall (p ≤ 0.05) in the lithium disilicate group cemented with Panavia SA at 25 °C and 54 °C, as well as the mid-palatal chamfer finish line and palatal margin in the LinkForce group cemented with Panavia SA at 25 °C and 54 °C. At the other measurement points, however, there was no significant difference (p > 0.05). Conclusions: The type of resin cement affects the internal and marginal fit of lithium disilicate crowns. At most measuring points, the cement preheating does not improve the internal and marginal fit of all lithium disilicate crowns.
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Anami, LC, JMC Lima, LF Valandro, CJ Kleverlaan, AJ Feilzer, and MA Bottino. "Fatigue Resistance of Y-TZP/Porcelain Crowns is Not Influenced by the Conditioning of the Intaglio Surface." Operative Dentistry 41, no. 1 (January 1, 2016): E1—E12. http://dx.doi.org/10.2341/14-166-l.
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SUMMARY Objectives The objective of this study was to investigate the effects of treatments of the intaglio surface of Y-TZP frameworks and luting agents on the fatigue resistance of all-ceramic crowns. Methods A research design was chosen that attempted to reduce the likelihood of Hertzian cracking and to increase the probability of fracture initiation at the intaglio surface of the framework. Ninety identical preparations were machined in a dentin-like epoxy composite. Each preparation was restored with a Y-TZP framework made by a CAD/CAM system and veneered using feldspathic ceramic. Prior to cementation the intaglio surface of the ceramic was treated using one of four treatments: 1) cleaning with isopropyl alcohol; 2) application of an overglaze; 3) sandblasting with 125 μm aluminum oxide powder; and 4) sandblasting with 30 μm silica powder (CJ). One of three luting cements were used: 1) zinc phosphate; 2) glass ionomer; and 3) adhesive resin cement (PN). All three cements were tested against frameworks that were alcohol cleaned. Only the PN cements were tested against frameworks that had been sandblasted or glazed. Altogether, six groups of 15 specimens each were tested. Fatigue resistance was evaluated using stepwise loads at 1.4 Hz until failure: 5000 cycles at maximum load of 200 N, followed by 10,000 cycles at maximum loads of 800, 1000, 1200, and 1400 N. The cement thickness and failure modes were analyzed using a stereomicroscope and scanning electron microscopy. The results were analyzed using the Kaplan-Meier and Mantel-Cox log rank tests (5%), a one-way analysis of variance, Tukey multiple comparison test, and Weibull nonparametric test. Results The predominant failure mode was chipping of the veneer. The crowns cemented with the adhesive resin cement exhibited chipping failure at higher mean loads than did crowns cemented with cements that usually do not bond strongly with dentin. When the adhesive cement was used, glazing and sandblasting intaglio framework surface treatments exhibited lower mean loads at chipping than did crowns whose intaglio surface was only cleaned with alcohol. Weibull analysis indicated that all specimens had a high ratio of late-to-early failures. Conclusions The fatigue experiment produced a pattern of failures that is very similar to that observed in clinical trials of Y-TZP crowns that are veneered with feldspathic porcelain. Crowns cemented with an adhesive resin cement exhibited chipping at a significantly higher mean load than those cemented with luting cements that do not usually form strong bonds with dentin. When cemented with adhesive resin cement, glazing or sandblasting the intaglio surface of the framework significantly reduced the mean fatigue loads at which chipping of veneers occurred, as compared to crowns whose intaglio surface had only been cleaned with alcohol. For this cement glazing or sandblasting the intaglio surface of the crown is not recommended.
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Ryan-Grigor, S., and J. P. Schulz-Rojahn. "SEISMIC DELINEATION OF STRUCTURE-CONTROLLED CARBONATE CEMENT AND POTENTIAL ECONOMIC IMPLICATIONS, ANGEL FIELD, NORTH WEST SHELF." APPEA Journal 35, no. 1 (1995): 280. http://dx.doi.org/10.1071/aj94017.
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Major carbonate-cemented zones occur in Late Jurassic Angel Formation sandstones of marine mass flow origin that contain large hydrocarbon reserves in the Angel Field, Dampier Sub-basin. Preliminary results suggest that poikilotopic dolomite cement is dominant. The carbonate-cemented zones are identifiable from wireline log response and 3D seismic data, and occur in discrete intervals with a cumulative thickness of approximately 165m at Angel-2. These intervals produce a zone of high amplitude reflections of about 100 ms two-way time. Field-wide seismic mapping indicates that these carbonate-cemented zones sharply abut the northern margin of a major east-west trending strike-slip fault system that traverses this field. The carbonate-cemented zones extend in a wedge-like shape towards the northeast and concentrate along the crest of the main structural trend.The results underscore the importance of 3D seismic data for a better estimation of reservoir risk and reserves in variably carbonate-cemented sandstones.The carbonate-cemented zones may represent a 'plume' related to migration of petroleum and/or carbon dioxide. Therefore delineation of major carbonate-cemented zones using seismic data may aid in the identification of petroleum migration pathways and pools in the North West Shelf. Alternatively, carbonate cements dissolved south of the major fault zone and possibly in downdip locations in which case dissolution pores may exist in these areas. Further research is required to evaluate these hypotheses.
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Gerhard, Christoph, Gerrit Mielke, Stephan Brückner, and Olaf Wermann. "Improving the Adhesiveness of Cemented Glass Components by DBD Plasma Pre-Treatment at Atmospheric Pressure." Applied Sciences 9, no. 24 (December 14, 2019): 5511. http://dx.doi.org/10.3390/app9245511.
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Cemented optical components and groups are essential devices for the realisation of modern systems and apparatuses used in a broad range of different applications such as telecommunications, imaging and even surgery. However, various parameters may affect the stability of cemented connections. In this context, the impact of dielectric barrier discharge plasma at atmospheric pressure on the adhesiveness of cemented glass components was evaluated in the present work. For this purpose, the plasma-induced change in surface wettability and energy as well as the cement’s adhesive pull strength was measured. Investigations were performed on samples, which were subject to different procedures of artificial ageing. It is shown that the adhesive pull strength of cemented glass components was notably increased after a short-term plasma treatment of merely 10 s due to an enhanced wettability of the applied UV-curing optical cement. The pull strength, i.e., the adhesiveness of cemented glasses was increased by a factor of 2.1 to 4.6, depending on the particularly applied artificial ageing procedure. The results and findings finally demonstrate the high potential of the applied short-term plasma treatment as a cleaning and surface activation step in optics manufacturing on an industrial scale.
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Fard, Asa Yazdani, Zuryati Ab Ghani, Zaihan Ariffin, and Dasmawati Mohamad. "Single blinded in-vitro study comparing microleakage between CAD/CAM crowns milled out of feldspathic ceramic and resin nano ceramic, cemented with three resin cements." Bangladesh Journal of Medical Science 18, no. 4 (August 30, 2019): 764–72. http://dx.doi.org/10.3329/bjms.v18i4.42883.
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Background: Studies on microleakage of Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) crowns are abundant. However many of them are inconclusive, especially those using self adhesive cements.
Aims: To compare the microleakage between CAD/CAM crowns milled out of feldspathic ceramic and resin nano ceramics, cemented with three resin cements.
Materials and Methods: Crown preparation was made on 54 extracted human premolars. Impressions were captured optically using CEREC 3D machine intraoral camera, and crowns were milled from feldspathic ceramic (CEREC® Blocs PC, VITA) and resin nano ceramic (Lava™ Ultimate CAD/CAM Restorative, 3M ESPE) blocks. The crowns were then cemented with three cements (n = 9); RelyX™ U200 Self-Adhesive Resin Cement (3M ESPE); NX3 Nexus ® cement with two-step etch-and-rinse adhesive (Kerr Corporation) or three/multistep etch-and-rinse resin cement, Variolink® II/Syntac Classic (Ivoclar Vivadent). The specimens were kept in water for 24 hours, thermocycled, and then soaked in methylene blue dye for 24 hours, before being sectioned mesiodistally. Microleakage was assessed using a fivepoint scale using stereomicroscope. Statistical analysis of the data was carried out using ONEWay ANOVA.
Results: CEREC® Blocs PC crowns showed significantly less microleakage (p< 0.001) compared to Lava™ Ultimate. RelyX™ U200 showed significantly lower microleakage (p< 0.001) compared to other cements. Combination of Lava™ Ultimate crown cemented with RelyX™ U200 showed the least microleakage (p< 0.001).
Conclusions: The microleakage scores were affected by the types of crown and cements.
Bangladesh Journal of Medical Science Vol.18(4) 2019 p.764-772
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Zheng, Qi Wen, Chen Wang, and Jian Wei Zhang. "The Strength and Stress-Strain Behavior of the Cemented Rockfill." Advanced Materials Research 598 (November 2012): 565–68. http://dx.doi.org/10.4028/www.scientific.net/amr.598.565.
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The cemented rockfill is mixed with cement, water and the siltstone rockfill with a certain mixing proportion. To study the strength and stress-strain behavior of the cemented rockfill, two groups of triaxial tests are carried out under the saturated and consolidated-drained conditions. One group specimens don’t include cement while the other group specimens include. The test results show that the cemented rockfill is a kind of elastoplastic material and the structure of the cemented rockfill is forced due to the effect of cementation. Compared with rockfill, the initial tangent elastic modulus, strength and cohesion of the cemented rockfill increase apparently, the residual strength and internal friction angle of the cemented rockfill increase a little, the maximum volume strain of the cemented rockfill decreases apparently.
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Vohra, Fahim, Manea Altwaim, Abdulaziz S. Alshuwaier, Abdullah Alomayri, Modhi Al Deeb, Yasser F. AlFawaz, Mohammed Alrabiah, Khold Al Ahdal, Laila Al Deeb, and Tariq Abduljabbar. "Bond integrity and microleakage of dentin-bonded crowns cemented with bioactive cement in comparison to resin cements: in vitro study." Journal of Applied Biomaterials & Functional Materials 18 (January 2020): 228080002090576. http://dx.doi.org/10.1177/2280800020905768.
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Objective: The aim was to compare restorative marginal integrity of ceramic crowns luted with bioactive and resin cements using micro-computed tomography (micro-CT) microleakage evaluations and bond strength assessment. Methods: Thirty molar teeth were prepared by sectioning and polishing for dentin exposure for resin cement build-ups. Teeth were randomly divided among three groups of cements: (1) bioactive (ACTIVA); (2) glass ionomer cement (GIC; Ketac Cem); and (3) resin luting agent (Nexus 3). Bonding regime and build-ups (4 mm × 2 mm) were performed using the recommended protocol. For microleakage assessment, 30 premolar teeth were prepared for dentin-bonded crowns using lithium disilicate ceramic and the computer-aided design and computer-aided manufacturing technique. Crowns were cemented with standard load, cement amount, and duration using three cements (Group A: bioactive; Group B: GIC; Group C: resin) and photopolymerized. Cemented crowns were evaluated for volumetric infiltration using micro-CT (Skyscan, Bruker 1173- at 86 kV, 93 µA, 620 ms) after immersion in 50% solution of silver nitrate (AgNO3) (24 hours). Shear bond strength (SBS) was assessed by fracture of cement build-ups at a cross-head speed of 0.5 mm/min in a universal testing machine. Results: Mean SBS among bioactive (21.54 ± 3.834 MPa) specimens was significantly higher than that for GIC (14.08 ± 3.25 MPa) specimens ( p < 0.01), but they were comparable to resin samples ( p > 0.05) (24.73 ± 4.32 MPa). Microleakage was significantly lower in crowns luted with bioactive (0.381 ± 0.134) cement compared to GIC (1.057 ± 0.399 mm3) ( p < 0.01) and resin (0.734 ± 0.166 mm3) ( p = 0.014) cemented crowns. The type of luting agent had a significant influence on the microleakage of crowns and bond strength to dentin ( p < 0.05). Conclusion: Bioactive cement exhibited less microleakage and comparable SBS to resin luting agents in in vitro conditions.
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Huang, Siyang, Jing Cao, Yunfei Song, Zhigang Song, Hong Liu, and Lin Tian. "Study on Microstructure of Cemented Organic Soil in Dianchi Lake, China." Applied Sciences 13, no. 3 (January 31, 2023): 1825. http://dx.doi.org/10.3390/app13031825.
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The organic soil in the Dianchi Lake area contains much humic acid (HA), and the impact of HA on cemented soil has attracted much attention. In this study, test soil is prepared based on the actual HA content of the soil in Dianchi Lake, and cement is added to prepare samples. Unconfined compressive strength (UCS), scanning electron microscopy (SEM), energy-dispersive analysis (EDS), and X-ray diffraction (XRD) tests are conducted on the samples. The strength development and microstructure changes of cemented organic soil are studied. The results show that (1) cemented soil strength decreases with the increase in HA content and increases with the cement mixing ratio; (2) SEM and EDS tests show that with the increase in HA content, the connection between soil particles gradually changed from surface–surface to point–surface, point–edge, or point–point connection. A large overhead structure is inside the cemented soil, and its integrity weakens with increased HA content. However, elements such as Ca, Si, and Al exist in the pores of cemented soil, indicating that cement hydration products are cemented between soil particles. XRD testing shows that with the increase in HA content, the intensity of the diffraction peaks of hydration products in cemented soil gradually decrease. (3) In general, HA will gradually deteriorate the integrity of cemented soil and reduce its strength. When the HA content is more than 15%, the effect of HA on strength is more prominent. However, increasing the cement mixing ratio can effectively weaken HA’s negative effect on cemented soil’s strength. When the cement mixing ratio is between 15% and 25%, the strength of cemented soil with high HA content can be effectively increased. However, this approach is not conducive to the protection of the environment.
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Yu, Jianlin, Zihao Mao, Jiajin Zhou, Zhongxiang Yu, Xiangwu Liu, and Xiaonan Gong. "Experimental Study on Engineering Properties of Cemented Soil with High Water Content." Applied Sciences 13, no. 2 (January 10, 2023): 937. http://dx.doi.org/10.3390/app13020937.
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A series of unconsolidated-undrained triaxial tests and unconfined compressive strength (UCS) tests for cemented soils with different curing times were carried out in this research. In total, three cemented soil mixtures with different cement contents were adopted in the tests, and the confining pressure was controlled in the range of 100–1600 kPa. The influence of curing time, cemented soil mixture ratio and confining pressure on the compressive and shear capacity of cemented soil was analyzed based on the test results. The test results indicate that the cement content and curing time both had a great influence on the strength of cemented soil, the UCS of the cemented soil increased linearly with the curing time under the semi-logarithmic coordinate, the cemented soil exhibited strain softening characteristics in the axial shear tests, and the maximum deviatoric stress of the cemented soil increased with the increase in confining pressure. A linear correlation was found between the cohesion and the UCS of cemented soil, and the cohesion was about 0.40 times the compressive strength.
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Dong, Xu, Mingdong Wang, Minyuan Song, and Ning Hou. "Engineering Properties and Microscopic Mechanisms of Composite-Cemented Soil as Backfill of Ultra-Deep and Ultra-Narrow Foundation Trenches." Applied Sciences 13, no. 3 (February 2, 2023): 1952. http://dx.doi.org/10.3390/app13031952.
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The backfilling of lime soil in ultra-deep and ultra-narrow foundation trenches is a difficult construction link, and ordinary-cemented soil has drawbacks, including poor strength, impermeability, and frost resistance. To solve these problems, fly ash (FA)–water glass (WG)-composite-cemented soil is developed based on a background project. The three-factor orthogonal tests are conducted on the unconfined compressive strength (UCS) of the composite-cemented soil, and the optimal engineering mix proportion is proposed for the FA-WG-composite-cemented soil. Its UCS is compared with that of cemented soil only doped with FA or WG (FA- and WG-cemented soil). In addition, the cyclic wetting–drying tests, cyclic freeze–thaw tests, and impermeability tests are carried out to study the endurance of the composite-cemented soil in cold regions rich in water. The hydration products of the composite-cemented soil are investigated through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, and the curing mechanism of the composite-cemented soil is discussed from the microscopic perspective. The research results indicate that the mixing ratio of cement is crucial to the strength development of the cemented soil; the mixing ratio of FA greatly influences the strength development of the cemented soil in the middle and late stages; the mixing ratio of WG only slightly affects the strength. The ratio of cement, FA, and WG of 9%:12%:3% is the optimal engineering mix proportion of the composite-cemented soil. Compared with ordinary-cemented oil and FA- and WG-cemented soil, the composite-cemented soil shows significantly improved compressive load-bearing capacity. The permeability coefficient of the composite-cemented soil is always obviously lower than that of the ordinary-cemented soil after any curing period. Despite the mass loss, the composite-cemented soil is superior to the ordinary one in overall endurance after wetting–drying and freeze–thaw cycles. Through SEM and XRD analysis, the content of hydration products of the composite-cemented soil is found to be obviously higher than that of ordinary-cemented soil after any curing period, and the hydrates exert stronger cementing action on soil particles in the composite-cemented soil. The contents of C-S-H gel and Aft crystals in the composite-cemented soil are apparently larger than those in the ordinary-cemented soil. Under the alkali activation of WG, the FA produces free SiO32− and AlO2−, which undergo the polymerization reaction with Ca2+ to generate C-S-H gel and C-A-H gel, further promoting the hydration of cement.
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Santos-Neto, Oswaldo, Letícia Gonçalves, Etevaldo Maia-Filho, Adriana Malheiros, Leily Firoozmand, Paulo Villis, Andres Cardenas, and Rudys Tavarez. "Retention of cemented zirconia copings on TiBase abutments." Acta Odontológica Latinoamericana 34, no. 3 (December 2021): 214–20. http://dx.doi.org/10.54589/aol.34/3/214.
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This study evaluated the influence of resin cements and glass ionomers on tensile strength and types of failure of zirconia copings cemented on titanium base abutments. Forty-two samples were prepared, which were formed by a Cone Morse implant, a titanium abutment with the fixing screw, and a zirconia structure made using a CAD/CAM system. The samples (n = 42) were randomly distributed according to the cementing agent: resin-modified glass ionomer cement (RelyX Luting 2), self-adhesive resin cement (RelyX U200), and self-curing resin cement (Multilink N). After cementation of the copings, half of the samples from each group (n = 7) were randomly selected and subjected to thermocycling (5000 cycles). A tensile load test was performed on a universal testing machine until failure occurred (1 mm). In addition, the type of failure was analyzed using the two-way analysis of variance test and Tukey’s post-hoc test (α = 0.05). Lower tensile load was observed for the glass ionomer cement (p < 0.001) regardless of the evaluation period. After thermocycling, a significant reduction in tensile load values was verified for both evaluated cements (p = 0.047). For the resin cements, failures were predominantly of the screw fracture type (82.1%) already with the use of glass ionomer cement, and 28.5% of the failures were of an adhesive type between the zirconia coping and the cement. Resin cements have better stability under tensile load compared to resin glass ionomers when cementing zirconia copings on titanium base abutments.
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Wang, Li Feng. "Orthogonal Test and Multi-Element Linear Regression Analysis of Compressive Strength of Nanometer Silicon Cemented Soil." Advanced Materials Research 317-319 (August 2011): 34–41. http://dx.doi.org/10.4028/www.scientific.net/amr.317-319.34.
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Cement-stabilized soil has been widely used to ground treatment, tracing of foundation pit, water resistance. Additives in cemented soil play an important role in improving its basic properties of cemented soil. In this paper, a new kind of additive, Nanometer Silicon Oxide (SiO2-x), was incorporated into cemented soil. Undrained triaxial compression tests were performed to discuss the reinforced effect of the nanometer silicon on the strength property of the cemented soil. Four main factors that influence the compressive strength of the nanometer silicon cemented soil (NCS) are considered: cement content, nanometer material content, confining pressure, and water\cement ratio. Based on orthogonal tests, the paper analyzed quantitatively the main influence factors of the compression strength of NCS and presented the optimum mix combination. A linear regression model for the compression strength were proposed. Finally, some conclusions have been achieved.
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Nu'man, Fareed Ghiab, and Mohammed F. Moutlak. "ROOT REINFORCEMENT USING CAST POST CEMENTED WITH DIFFERENT TYPES OF CEMENTS." Mustansiria Dental Journal 3, no. 2 (April 16, 2018): 122–26. http://dx.doi.org/10.32828/mdj.v3i2.624.
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The purpose of this in-vitro study is to evaluate and compare the fractureresistance of endodontically treated teeth restored using cast posts cemented withdifferent types of cement. Thirty intact human maxillary central incisors were selectedfor this study. The crowns were removed and endodontic therapy were done on theroots, which were then prepared to receive cast posts, after their fabrication, the castposts were cemented with zinc phosphate cement (group I), resin modified glassionomer cement (group II),and resin cement (group III). The samples were subjectedto compressive fracturing loads by a Zwick testing machine at a cross head speed of5mm/min., with an angle of 45º to the long axis of the tooth. The results showed thatthe posts cemented with resin cement exhibited the highest mean failure load followedby posts cemented with resin modified glass ionomer cement , while posts cementedwith zinc phosphate cement exhibited the lowest mean failure load.
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Zheng, Juanrong, Lijie Guo, Xiaoxiao Sun, Wenchen Li, and Qi Jia. "Study on the Strength Development of Cemented Backfill Body from Lead-Zinc Mine Tailings with Sulphide." Advances in Materials Science and Engineering 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/7278014.
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The unconfined compressive strength (UCS) development of cemented backfill materials for lead-zinc mine tailings with sulphide was studied. The results showed that the UCS of the cemented backfill body with ordinary Portland cement (OPC) as binder decreased in the later curing days, regardless of particle size. Under the same conditions, the higher the OPC content, the higher the UCS of the cemented backfill body, and the UCS of the cemented backfill body began to decrease at the longer curing days. Under the same conditions, the finer the tailings, the lower the UCS of the cemented backfill body at each age, and the UCS of the cemented backfill body began to decrease at the earlier curing age. X-ray diffraction analysis (XRD) showed that the reduction of the UCS of the cemented backfill body was related to the formation of an expansive substance (expansive gypsum) in the cemented backfill body, which led to the cracking of the test sample. In the cemented backfill materials of coarse tailings of lead-zinc mine, the composite binder formed by OPC and calcined kaolin (CK) containing metakaolin was used; the amount of calcium hydroxide, the hydration product of cement, was reduced or eliminated due to the pozzolanic reaction of metakaolin; and the amount of expansive gypsum was reduced or eliminated, so the UCS of the cemented backfill body increased within 360 days of curing.
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Lawrie, C. M., M. Schwabe, A. Pierce, R. M. Nunley, and R. L. Barrack. "The cost of implanting a cemented versus cementless total knee arthroplasty." Bone & Joint Journal 101-B, no. 7_Supple_C (July 2019): 61–63. http://dx.doi.org/10.1302/0301-620x.101b7.bjj-2018-1470.r1.
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Aims The aim of this study was to compare the actual cost of a cemented and cementless total knee arthroplasty (TKA) procedure. Materials and Methods The cost of operative time, implants, cement, and cementing accessories were included in the overall cost of the TKA procedure. Operative time was determined from a previously published study comparing cemented and cementless implants of the same design. The cost of operative time, implants, cement, and cementing accessories was determined from market and institutional data. Results Mean operative time for cemented TKA was 11.6 minutes longer for cemented TKA than cementless TKA (93.7 minutes (sd 16.7) vs 82.1 minutes (sd 16.6); p = 0.001). Using a conservative published standard of $36 per minute for operating theatre time cost, the total time cost was $418 higher for cementing TKA. The cost of cement and accessories ranged from $170 to $625. Overall, the calculated cost of cemented TKA is $588 to $1043, depending on technique. The general increased charge for cementless TKA implants over cemented TKA implants was $366. Conclusion The overall procedural cost of implanting a cementless TKA is less than implanting a cemented TKA. Cost alone should not be a barrier to using cementless TKA. Cite this article: Bone Joint J 2019;101-B(7 Supple C):61–63
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Kumar, Rajneesh, Nisha Garg, Poonam Bogra, Vineeta Nikhil, Amit Garg, and Anamika Thakur. "The Effect of Different Post Materials and Cements on Fracture Resistance of Endodontically Treated Teeth–An in Vitro Study." Dental Journal of Advance Studies 04, no. 01 (April 2016): 038–43. http://dx.doi.org/10.1055/s-0038-1672043.
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Abstract Objective: To evaluate the effect of various post materials and cements on fracture resistance of endodontically treated teeth. Material and methods: Three post systems; custom made Ni-Cr post and core, prefabricated stainless steel and carbon fibre post with composite core and two different luting cements i.e glass ionomer and resin cements were used. Results and conclusions: Carbon fibre post cemented with resin cements showed higher failure load than Ni-Cr and stainless steel post and resin cement performed better than glass ionomer cement, the mode of fracture was more favourable with carbon fibre post than in metallic post.
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Li, Jian Zhong, Li Chun Zhuo, and Xi Ni. "Behavior of Cemented Reticulate Red Clay." Advanced Materials Research 446-449 (January 2012): 1666–69. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.1666.
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Mechanical properties of cemented reticulate red clay were studied in present research. Test results show that: (1) shear strength of cemented reticulate red clay increase exponentially as the increasing of cement content; (2) shear strength of cemented reticulate red clay decrease polynomially as the increasing of water content; (3) mechanical properties of cemented reticulate red clay affected significantly by curing time and curing confined pressure. In order to study viscous properties of cemented reticulate red clay, cemented reticulate red clay specimens were compressed in triaxial chamber at different shear rate. Results of the compression tests show that it is obvious that the axial strain-deviator stress relationship of cemented reticulate red clay affects by the strain rate.
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Yang, Luling, and Richard D. Woods. "Shear stiffness modeling of cemented clay." Canadian Geotechnical Journal 52, no. 2 (February 2015): 156–66. http://dx.doi.org/10.1139/cgj-2012-0377.
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The shear modulus and damping of cemented clay are investigated using ultrasound transducers, bender elements, and a resonant column device. The model SimSoil-CC, based on the Pestana and Salvati (published in 2006) model SimSoil, is proposed to represent the maximum shear modulus and stress–strain behavior (under cyclic loading conditions) at small strains for the cemented clay. The model can also be used for uncemented clay when the cementation parameter is set to zero. Model parameters are determined for three types of clay (kaolinite, bentonite, and the equal mix of kaolinite and bentonite) and two types of cementation agents (type III Portland cement and gypsum). The model SimSoil-CC is validated using the laboratory test data of this study and data from other studies in literature. The SimSoil-CC model can be very useful for performing earthquake site response analysis for naturally cemented clay sites or sites that have been improved by cementation. In addition, a relationship between the cementation parameter acc(CC)2 (acc, cement material constant; CC, dry cement content) and the unconfined compression strength is proposed. The relationship simplified modeling for naturally cemented clay soil or cemented clay whose cement contents and cementation type are otherwise difficult to determine. This research advances the understanding of cemented clay by providing a database of test results and creation of a model that can be used to predict the response of cemented clay soils to dynamic loads.
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de Jesus Tavarez, Rudys Rodolfo, Mateus R. Tonetto, EM Maia Filho, Valdimar S. Valente, Carlos E. Francischone, CD Vilarinho Soares de Moura, CE Francischone Júnior, Antonio M. Silva, and Izabella S. Ribeiro. "Marginal Fit Metal–Ceramic and In-Ceram Single Crown Cement retained in Implant-supported Abutments." Journal of Contemporary Dental Practice 17, no. 12 (2016): 969–72. http://dx.doi.org/10.5005/jp-journals-10024-1965.
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ABSTRACT Introduction This study evaluated the cervical fit of cemented metal–ceramic and In-Ceram implant-supported crowns, before and after the cementing procedure. Materials and methods Twenty crowns cemented on implant abutments are divided into two groups (n = 10): Group 1 – cemented metal–ceramic crowns and group 2 – cemented In-Ceram crowns. The marginal adaptations before and after cementation were evaluated in a comparison microscope with an error of 1 μm. All crowns were cemented with zinc phosphate cement. Results The cervical misalignment of cemented crowns before cementation (52.65 ± 11.83 and 85.73 ± 14.06 μm) was lower than that after cementation (66.80 ± 15.86 and 89.36 ± 22.66 μm). Conclusion The cementing procedure interferes with the marginal fit of cemented crowns on implant abutments, with the prosthesis having better adaptation before cementation. Cemented metal–ceramic crowns exhibited better cervical adaptation than In-Ceram crowns cemented before and after the cementing procedure. Clinical significance The maintenance of gum health and the longevity of prosthetic restorations are closely related to the restoration's marginal integrity. How to cite this article Valente VS, Francischone CE, Vilarinho Soares de Moura CD, Francischone Júnior CE, Silva AM, Ribeiro IS, Maia Filho EM, Bandéca MC, Tonetto MR, de Jesus Tavarez RR. Marginal Fit Metal–Ceramic and In-Ceram Single Crown Cement retained in Implant-supported Abutments. J Contemp Dent Pract 2016;17(12):969-972.
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Kumar, Manjit, Abhishek Gupta, and Vandana Chabhra. "Comparative Evaluation of Tensile Bond Strength of Nickel-Chromium Alloy to Dental Enamel Using Different Resin Cements – An In Vitro Study." Dental Journal of Advance Studies 04, no. 03 (December 2016): 170–76. http://dx.doi.org/10.1055/s-0038-1672065.
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Abstract Aim: The aim of this study was to evaluate and compare the tensile bond strength of nickel-chromium alloy to dental enamel by using four different resin cements. Materials and Methods: 40 extracted central incisor teeth embedded in acrylic blocks were flattened not to expose dentin. Wax rectangular blocks of 5 mm length, 5 mm width and 1 mm height with a loop were invested and casted using Nickel-Chromium alloy by conventional induction casting method and sandblasted. Then casted rectangular blocks and 40 tooth embedded acrylic samples were divided into four groups (10 each) and cemented to tooth enamel following manufacturer's instructions as; GroupAcemented using RelyX U200, Group B cemented using Smartcem 2, Group C cemented using Multilink Speed and Group D cemented using Multilink N and then stored in artificial saliva for 24 hours. The direct pull tensile test was carried out on Universal Testing Machine at cross head speed of 0.5mm/min. Results: One way ANOVA showed a highly statistically significant (p<.01) difference between all the four resin cements. Post Hoc Tests- Multiple comparisons showed highly statistically significant (p< 0.01) difference between RelyX U200: Multilink N, Smartcem 2: Multilink Speed, Smartcem 2: Multilink N, Multilink Speed: Multilink N. Difference between RelyX U200 : Smartcem 2 and RelyX U200 : Multilink Speed was statistically significant(p< 0.05). Conclusion: Self etch resin cement (Multilink N) showed maximum mean tensile bond strength as compared to self-adhesive resin cements (Smartcem 2, RelyX U200 and Multilink Speed). Clinically the greatest advantage of self-adhesive cements is the easy and fast application technique. But this time saving technique is not as effective as self-etch resin luting agents. The presumed benefit of saving time with self-adhesive luting agents may only be realized at the expense of compromising bond strength.
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Billi, F., A. Kavanaugh, H. Schmalzried, and T. P. Schmalzried. "Techniques for improving the initial strength of the tibial tray-cement interface bond." Bone & Joint Journal 101-B, no. 1_Supple_A (January 2019): 53–58. http://dx.doi.org/10.1302/0301-620x.101b1.bjj-2018-0500.r1.
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AimsLoosening of the tibial component after total knee arthroplasty (TKA) is a common indication for revision. Increasing the strength of the initial tibial implant/cement interface is desirable. There is little information about the surgical techniques that lead to the highest strength. We investigated the effects of eight variables on the strength of the initial tibial baseplate/cement interface.Materials and MethodsA total of 48 tibial trays were cemented into acrylic holders using cement from two manufacturers, at three different times (early, normal, and late) using two techniques: cementing the tibial plateau or the plateau and the keel; and involving two conditions of contamination with marrow fat (at the metal/cement and cement/cement interfaces). Push-out tests were performed with load continuously recorded.ResultsCompared with normal conditions, early cementing increased the mean strength of the interface when using the two cements, Simplex and Palacos, by 48% and 72%, respectively. Late cementing reduced the strength by 47% and 73%, respectively. Cementing the keel increased the mean strength by 153% and 147%, respectively, for the two cements. Contamination of the metal/cement interface with fat reduced the mean strength by 99% and 94% for the two cements but adding cement to the underside of the tibial tray prior to insertion resulted in the mean strength being lowered by only 65% and 43%, respectively.ConclusionIn order to maximize the strength of the tibial tray/cement interface, cement should be applied to the component soon after mixing, contamination of the interface should be avoided, and the keel and the plateau should be cemented.
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Farid, Farzaneh, Khadijeh Rostami, Sareh Habibzadeh, and MohammadJavad Kharazifard. "Effect of cement type and thickness on push-out bond strength of fiber posts." Journal of Dental Research, Dental Clinics, Dental Prospects 12, no. 4 (December 19, 2018): 277–82. http://dx.doi.org/10.15171/joddd.2018.043.
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Background. This study investigated the effect of the thickness of two resin cements on push-out bond strength of fiber posts to root dentin. Methods. Sixty decoronated single-rooted teeth were endodontically treated. The specimens were then randomly allocated to two groups (n=30); group 1: drill size 90 w, matching the size of fiber posts used; group 2: drill size 110, larger than the posts. The specimens in each group were divided into 2 subgroups (n=15); subgroup SE, in which the posts were cemented with self-etch Panavia F2.0 and subgroup SA, in which self-adhesive Panavia cement was used. After 72 hours, 2 slices with 1 mm of thickness were prepared from the mid-root of each specimen. Push-out bond strength test was performed in a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed with two-way ANOVA and t-test. Results. The mean bond strengths of the posts cemented in matched-size spaces for SE and SA groups were 4.02±1.6 and 4.12±2.3 MPa, respectively. For posts cemented in oversized spaces, the values were 4.9±2.3 and 2.8±1.3 MPa, respectively. In matched-size spaces, there was no significant difference between the two groups. Conclusion. The results of this study suggested that increasing the cement thickness would reduce the bond strength of fiber posts to root dentin when self-adhesive cements are used; however, self-etch adhesives were not affected.
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Herion, Tracy, Jack L. Ferracane, and David A. Covell. "Three Cements Used for Orthodontic Banding of Porcelain Molars." Angle Orthodontist 77, no. 1 (January 1, 2007): 94–99. http://dx.doi.org/10.2319/100505-350r.1.
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Abstract Objective: Objectives of this study were to (1) compare the mean shear-peel bond strength of orthodontic bands luted to porcelain molar denture teeth with glass ionomer cement (GIC), resin-modified glass ionomer cement (RMGIC), or compomer cement; (2) assess the amount of cement remaining on the teeth after debanding; and (3) compare the survival times of the cemented bands subject to mechanical fatigue. Materials and Methods: Sixty banded denture teeth (20 per cement group) were used to determine shear-peel bond strength, and 30 banded denture teeth (10 per cement group) were used to determine fatigue survival time. Shear-peel bond strength was determined with a universal testing machine, and groups were compared by one-way analysis of variance. The amount of cement remaining on the teeth after band removal was scored, and a chi-square test was used to compare groups. Fatigue testing was conducted in a ball mill, and a log-rank test was used to compare differences in survival times. Results: No differences were found in mean shear-peel bond strength among the three groups. The amount of cement remaining on the teeth varied between the compomer and GIC groups (P = .01), with more compomer cement remaining relative to GIC. The mean survival times of bands cemented with compomer or RMGIC were longer than for bands cemented with GIC (P < .001). Conclusion: The findings show that on porcelain teeth the band cements have comparable mean shear-peel bond strengths, but that band retention with RMGIC and compomer cement are superior to GIC when subjected to simulated mechanical fatigue.
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Hung, Jui-Pin, Yu-Wei Bai, Chung-Qua Hung, and Tsui-Er Lee. "Biomechanical Performance of the Cemented Hip Stem with Different Surface Finish." Applied Sciences 9, no. 19 (September 30, 2019): 4082. http://dx.doi.org/10.3390/app9194082.
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The integrity of the cemented fixation interface is responsible for the long-term longevity of artificial hip prostheses. Metallic stems with roughened surfaces are considered to provide stronger adhesion with cement. However, clinical studies have reported that roughened stems show a lower survival rate than polished stems. These studies clearly reveal that the causes of artificial stem loosening are very complicated and multifaceted. Therefore, this study was conducted to investigate the mechanical effect of stem surface finish in cemented hip replacement. To accomplish this, a series of cement–metal specimens were tested configurations to assess the mechanical characteristics of the cement–metal interface specimens. A finite elemental model of cemented femoral prostheses was then created, in which the cement–stem interface was assumed to be in different bonding states according to the experimentally measured interface properties. The failure probabilities of the cement mantle and cemented interface under physiological loadings were evaluated. Experimental results indicate that the polished metal produced higher interfacial tensile and lower shearing strengths than the roughened metal. The polished stems were predicted to induce a lower failure probability of cement mantle and higher integrity of the cement–stem interface when compared to the roughened stem. Overall, current results provide significant evidence to support the clinical outcomes of cemented hip prostheses with different stem surface finishes.
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Kumbasar, Ulaş, and Pramod Bonde. "Delayed presentation of bone cement implantation syndrome requiring extracorporeal membrane oxygenation support." Turkish Journal of Thoracic and Cardiovascular Surgery 29, no. 3 (July 1, 2021): 412–14. http://dx.doi.org/10.5606/tgkdc.dergisi.2021.21709.
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Bone cement implantation syndrome is a rare and potentially fatal complication which may occur following cemented bone surgery. Herein, we present a case of delayed and fatal presentation of bone cement implantation syndrome following cemented spinal surgery, despite mechanical support with extracorporeal mechanical oxygenation.
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Dincer, Banu, and Aslihan Ertan Erdinc. "A comparison between zinc polycarboxylate and glass ionomer cement in the orthodontic band cementation." Journal of Clinical Pediatric Dentistry 26, no. 3 (April 1, 2002): 285–88. http://dx.doi.org/10.17796/jcpd.26.3.r730148542380658.
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Fixed orthodontic appliances have been held responsible for demineralization and caries since the time they were first introduced. Zinc polycarboxylate and glass ionomer cements are the primary materials used in band cementing. In this study, we evaluated the re-cementing frequencies, enamel demineralization and the degree of cement remains of the bands cemented with glass ionomer and zinc polycarboxylate cements. We have concluded that given the retentive properties and enamel decalcification degree, the glass ionomer cements are to be preferred by the orthodontist.
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Özlek, Esin, Prasanna Neelakantan, Jukka Pekka Matinlinna, Sema Belli, Mehmet Ugur, and Idrıs Kavut. "Adhesion of Two New Glass Fiber Post Systems Cemented with Self-Adhesive Resin Cements." Dentistry Journal 7, no. 3 (August 1, 2019): 80. http://dx.doi.org/10.3390/dj7030080.
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The aim of this in vitro study was to evaluate the adhesion strength of two new fiber post systems (FiberSite™ Post and Cytec™ Blanco Post) cemented with two different adhesive resin cements (Panavia™ SA and Maxcem™ Elite). Root canals of sixty extracted human mandibular premolars were prepared using ProTaper Universal™ rotary files (Dentsply Sirona Endodontics, York, PA, USA). The root canals were irrigated with 5.25% sodium hypochlorite (NaOCl) during instrumentation. After root canal preparation, the canals were irrigated with 2 mL of 17% EDTA (1 min), followed by 2 mL of 5.25% (5 min) NaOCI, and 2 mL saline. The root canals were dried with paper points and divided randomly into two study groups (n = 30) according to the type of post system: Group 1, FiberSite™ Post (MegaDental, Partanna, Italy); and group 2, Cytec™ Blanco Post (Hahnenkratt, Königsbach-Stein, Germany), with one of the two adhesive resin cements: Subgroup A, Panavia™ SA Cement Plus Automix (Kuraray, Osaka, Japan); subgroup B, Maxcem™ Elite (Kerr, Orange, CA, USA). Following thermocycling, the adhesion strength was evaluated using the push-out adhesion (bond) strength test. Fractographic analysis was performed using stereomicroscope. The data were analyzed using two-way analysis of variance (p = 0.05). The adhesion strength values of both the posts were significantly higher when cemented with subgroup B (Maxcem™ Elite). The highest adhesion strength value was demonstrated by group 1B (FiberSite™ post cemented with Maxcem™ Elite cement). The type of post did not have a significant impact on the bond strength values for either cement material.
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Alfredo, Edson, Emanuel Soares de Souza, Melissa Andréia Marchesan, Silvana Maria Paulino, Ricardo Gariba-Silva, and Manoel Damião Sousa-Neto. "Effect of eugenol-based endodontic cement on the adhesion of intraradicular posts." Brazilian Dental Journal 17, no. 2 (2006): 130–33. http://dx.doi.org/10.1590/s0103-64402006000200009.
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The present study evaluated, in vitro, the influence of an eugenol-based endodontic sealer (EndoFill) on the adhesion of intra-radicular posts cemented with a resin-based cement (Enforce) ou a zinc phosphate cement. Twenty-four single-rooted maxillary canines were divided into 2 groups (n=12) and obturated with either gutta-percha points plus EndoFill or gutta-percha points alone (no cement). In each group, half of intracanal posts (n=6) were cemented with Enforce resin-based cement and half with zinc phosphate cement. Specimens were submitted to pull-out test in an Instron machine and tensile force was applied at a crosshead speed of 0.5 mm/min until post dislodgement. The maximum forces required for post removal was recorded (N) and means were submitted to statistical analysis by Kruskal-Wallis test (p<0.01). Posts cemented with zinc phosphate cement were significantly more retentive (353.4 N) than those cemented with Enforce (134.9 N) (p<0.01). Regarding the influence of the eugenol-based cement (EndoFill) on post retention, there was statistically significant difference (p<0.01) only between the groups cemented with Enforce, i.e., in the canals filled with EndoFill + guta-percha there was lower bond strength than in the canals filled with gutta-percha points alone (101.5 and 168.2 N, respectively). In conclusion, the zinc-phosphate-based cement showed greater post retention than the resin-based cement. The findings of this study suggest that the eugenol-containing sealer interfered with the adhesive properties of the resin-based cement.
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Knappe, Kevin, Christian Stadler, Moritz M. Innmann, Mareike Schonhoff, Tobias Gotterbarm, Tobias Renkawitz, and Sebastian Jaeger. "Does Additive Pressurized Carbon Dioxide Lavage Improve Cement Penetration and Bond Strength in Cemented Arthroplasty?" Journal of Clinical Medicine 10, no. 22 (November 17, 2021): 5361. http://dx.doi.org/10.3390/jcm10225361.
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The modern cementing technique in cemented arthroplasty is a highly standardized and, therefore, safe procedure. Nevertheless, aseptic loosening is still the main reason for revision after cemented total knee or cemented total hip arthroplasty. To investigate whether an additional carbon dioxide lavage after a high-pressure pulsatile saline lavage has a positive effect on the bone–cement interface or cement penetration, we set up a standardized laboratory experiment with 28 human femoral heads. After a standardized cleaning procedure, the test implants were cemented onto the cancellous bone. Subsequently, the maximum failure load of the bone–cement interface was determined using a material testing machine to pull off the implant, and the cement penetration was determined using computed tomography. Neither the maximum failure load nor cement penetration into the cancellous bone revealed significant differences between the groups. In conclusion, according to our experiments, the additive use of the carbon dioxide lavage after the high-pressure pulsatile lavage has no additional benefit for the cleaning of the cancellous bone and, therefore, cannot be recommended without restrictions.
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Loope, David, and Richard Kettler. "Rinded, Iron-Oxide Concretions in Navajo Sandstone Along the Trail to Upper Calf Creek Falls, Garfield County." Geosites 1 (December 31, 2019): 1–7. http://dx.doi.org/10.31711/geosites.v1i1.59.
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Concretions are hard rock masses, usually spheroidal, but commonly oblate or discoidal, that are formed by strongly localized precipitation of minerals in the pores of an otherwise weaker sedimentary rock (see Bates and Jackson, 1980, for a more extensive definition). The iron-oxide-rich concretions in the Jurassic Navajo Sandstone in southern Utah are unusual in two fundamental ways. First, they are cemented by iron oxide (Fe2O3, or Fe(OH)3); most other concretions are cemented by silica (SiO2), calcite (CaCO3), dolomite (CaMg(CO3)2), or siderite (FeCO3). Second, unlike other concretions, they are not strongly cemented throughout, but instead, the iron oxide is concentrated in a very strongly cemented, sharply defined, exterior rind or shell. In the smaller concretions, the entire interior lacks iron-oxide cement, and is similar to the rock outside the concretion; in the larger concretions, there is a central zone that is strongly cemented by iron oxide, but the sandstone between the central core and the rind has no iron-oxide cement.
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Han, S.-H., Y. Shimada, A. Sadr, J. Tagami, and S.-E. Yang. "Interfacial Evaluation of CAD/CAM Resin Inlays on the Cavity Floor Using Swept-source Optical Coherence Tomography." Operative Dentistry 45, no. 6 (September 30, 2020): 664–76. http://dx.doi.org/10.2341/19-141-l.
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Clinical Relevance When a resin nanoceramic inlay is cemented using self-adhesive cement, a universal dentin adhesive can be applied to the prepared cavity. The application of the adhesive before self-adhesive cement placement provides similar or better interfacial adaptation than without the adhesive. SUMMARY Purpose: The first objective of this study was to determine whether the luting material used for computer-aided design and computer-aided manufacture resin nanoceramic inlays affected interfacial adaptation. The second objective was to investigate whether application of a universal dentin adhesive before cementation affected interfacial adaptation. The final objective was to compare the inlay-side and dentin-side interfaces in the cement space. Methods and Materials: Seventy-four class I cavities were prepared on extracted human third molars. Cavities were optically scanned, and resin nanoceramic inlays were milled using Lava Ultimate blocks (3M ESPE). For the control groups, the fabricated inlays were cemented using Panavia V5 (Kuraray Noritake) or FujiCem 2 (GC). For the experimental groups, the teeth were randomly divided into groups I and II. Group I contained four subgroups using different luting materials; in all subgroups, the inlays were cemented and dual cured without pretreatment. Group II contained six subgroups in which inlays were cemented and dual cured after application of a universal dentin adhesive. After thermocycling, interfacial adaptation was measured using swept-source optical coherence tomography (SS-OCT) imaging and statistically compared among groups. Results: Interfacial adaptation was different depending on the luting material used (p<0.05). After application of a universal adhesive, some subgroups showed improved interfacial adaptation (p<0.05). In the comparison of inlay-side and dentin-side interfaces, no difference was found in interfacial adaptation (p>0.05). Conclusions: Interfacial adaptation for resin nanoceramic inlays differed with luting material. For some self-adhesive cements, application of a universal adhesive before cementation improved interfacial adaptation.
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Zhang, Jun, Wei Xu, Peiwei Gao, Lihai Su, Bai Kun, Li Yueyuan, and Yang Bohan. "Integrity and crack resistance of hybrid polypropylene fiber reinforced cemented soil." Journal of Engineered Fibers and Fabrics 17 (January 2022): 155892502110684. http://dx.doi.org/10.1177/15589250211068428.
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Cement is commonly used in the rapid construction of emergency airports; however, cemented soils have issues with integrity and crack resistance. For example, cemented soils can crack easily, and overall stability is insufficient. To address these problems, cemented soil is reinforced with hybrid polypropylene fiber, and the anti-flying property, anti-wear property, and crack resistance of polypropylene fiber reinforced cemented soil with varying fiber lengths, fiber contents, and fiber combinations are examined through flying tests, wear tests, and crack tests. Results show that the reinforcement of fiber can significantly improve the anti-flying property, anti-wear property, and crack resistance of cemented soil. The content and fiber length have a great impact on properties of fiber reinforced cemented soil. The ideal length and content of fine polypropylene fiber are 12 mm and 0.3%, respectively. The ideal combination of hybrid polypropylene fiber reinforced cemented soil is 0.3% coarse polypropylene fiber with the length of 38 mm and 0.3% fine polypropylene fiber with the length of 12 mm. In addition, hybrid polypropylene fiber reinforced cemented soil mechanical properties exceed those of single polypropylene fiber reinforced cemented soil.
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Dong, Xiao Qiang, and Xiao Hong Bai. "Study on the Electrical Model of Cemented Soil." Advanced Materials Research 168-170 (December 2010): 607–14. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.607.
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Cemented soil resistivity is one of its inherent properties which can be used to detect its unconfined compressive strength and polluted state. But the cemented soil resistivity is macroscopic showing of its microstructure conductivity. Its resistivity closely relates with resistivity of various material components, such as soil porosity, cement mixing ratio,etc. So further researching the electrical model of cemented soil is great significance. This paper introduces the existing cemented soil electrical model(Komine model). Then based on the microstructural observation of the SEM images of cemented soil, the problems of Komine model are pointed out. Furthermore a more reasonable microstructure is proposed. The new electrical model of cemented soil is set up on three hypotheses. This new model is composed of parallel structure and series structure. Some soil particles surrounded by the hydration products such as CSH or CASH connect with pore water parallel to form the series structure. The hydration products that continue to harden to form the cemented soil skeleton connect with soil particles and pore water to form the parallel structure. The new electrical model of cemented soil can explain better electrical conductive mechanism of cemented soil materials.
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Saurabh, Jain, Solanki Mahendra, Satish Rohra, and Rashmi Pal. "Cement Implantation Syndrome During Cemented Hemiarthroplasty and Review of Literature." Journal of Orthopaedic Education 2, no. 2 (2016): 69–73. http://dx.doi.org/10.21088/joe.2454.7956.2216.5.
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Xu, Bin, Wei Luo, De Gao Zou, Xian Jing Kong, and Yang Zhou. "The Numerical Simulation of the Triaxial Test of Cemented Coarse-Grained Soils." Advanced Materials Research 250-253 (May 2011): 2640–44. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2640.
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Cemented coarse-grained soils have both the properties of coarse-grained soils and concrete. This paper used discrete element method (DEM) to simulate of the drained monotonic load triaxial tests of coarse-grained soils and cemented coarse-grained soils respectively, the microscopic parameters of numerical models were calibrated based on the tests. The characteristics of the cemented coarse-grained soils and the microscopic mechanism were analyzed. The results showed that, the cemented coarse-grained soils have the higher modulus and strength compared with coarse-grained with adding the 3% cement in the specimens and appear the significant strain softening after the stress reaches the peak value; the deformation of the soil particles,the friction between soil particles and the crack of the cement bond are the mainly internal factors.
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Moris, Izabela Cristina Maurício, Juliana Elias de Oliveira, Adriana Cláudia Lapria Faria, Ricardo Faria Ribeiro, and Renata Cristina Silveira Rodrigues. "In Vitro Fit and Cementation Resistance of Provisional Crowns for Single Implant-Supported Restorations." Brazilian Dental Journal 26, no. 5 (October 2015): 468–73. http://dx.doi.org/10.1590/0103-6440201300289.
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Abstract: This study aimed to verify marginal fit and the effect of cement film thickness standardization on retention of provisional crowns made with prefabricated acrylic cylinders on abutments, using two temporary luting agents subjected or not to mechanical cycling. Provisional crowns were made from bis-acryl (Luxatemp Fluorescence) or methyl methacrylate (Duralay) resins on acrylic cylinders and marginal fit and cement film thickness were evaluated. For retention evaluation, crowns were cemented with two temporary luting agents: non-eugenol zinc oxide (Tempbond NE) or calcium hydroxide-based (Hydcal) cements and subjected to tensile strength in a universal testing machine. After cleaning, debonded crowns were cemented again, subjected to mechanical cycling and retention was reassessed. The results of marginal fit and cement film thickness were analyzed by Student's t-test while retention of cements before and after mechanical cycling was analyzed using a mixed linear model. Methyl methacrylate crowns presented greater marginal misfit (p=0.001) and occlusal cement film thickness (p=0.003) than the bis-acryl ones. No difference was observed at axial cement film thickness (p=0.606). Resins (p=0.281) did not affect crown retention, but luting agents (p=0.029) and mechanical cycling (p=0.027) showed significant effects. The only significant interaction was mechanical cycling*luting agents, which means that luting agents were differently affected by mechanical cycling (p=0.002). In conclusion, the results showed that bis-acryl resin associated to calcium-hydroxide luting agent provided the best retention and lower cement thickness.
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Taylor, K. G., and J. H. S. Macquaker. "Diagenetic alterations in a silt- and clay-rich mudstone succession: an example from the Upper Cretaceous Mancos Shale of Utah, USA." Clay Minerals 49, no. 2 (April 2014): 213–27. http://dx.doi.org/10.1180/claymin.2014.049.2.05.
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An understanding of the nature and scales of diagenetic variability within organic-rich mudstones is critical to the accurate assessment of shale-gas reservoir properties, as well as for elucidating chemical evolution pathways within mudstones. Here we integrate field observations with thin section descriptions (optical and electron optical techniques) and mineralogical data for the Blackhawk Member time-equivalent Mancos Shale in Book Cliffs, Utah, to determine the impacts of early and burial diagenesis on this mudstone succession.The detrital assemblage in the Mancos Shale comprises quartz-silt, feldspar, clay minerals, dolomite and organic matter (TOC of 1 to 2.5%). Biogenic silica is negligible. Field mapping reveals laterally continuous (km scale), ferroan dolomite cemented units up to 0.3 m thick, are present. These cemented units cap both coarsening-upward units (1 to 3 m thick), and stacked successions of coarsening-upward units (5 to 15 m thick). These upward-coarsening sediment packages, capped by dolomite cemented strata, correlate to bedsets and parasequences in updip settings. Pervasive cementation in these dolomite-cemented units is likely to have occurred prior to compaction as a result of bacterially mediated respiratory processes. Cementation at these levels is particularly evident because cement precipitation occurred during breaks in sediment accumulation below marine flooding surfaces. The abundance of dolomite cements highlights the importance of macroscopic-scale diagenetic carbonate mobility in these mudstones.In addition to carbonate-cements, diagenetic alteration and precipitation of quartz and alumina-silicate minerals are also important in these mudstones. Kaolinite is present both in uncompacted test of organisms and as vein fills in septarian concretions. Kaolinite precipitation is interpreted to have occurred prior to significant compaction and indicates that both silicon and aluminium were mobile during early diagenesis. We interpret the abundance of early diagenetic kaolinite cement to be the result of Al-mobilization by organic acids generated during organic matter oxidation reactions, with the Al sourced from poorly crystalline detrital aluminium oxides and clay minerals. There is also indirect evidence for burial diagenetic kaolinitization of feldspar grains. Quartz cement takes the form of quartz overgrowths and microcrystalline quartz crystals. Textures and CL spectra for the quartz microcrystalline cement suggests that recrystallization of biogenic silica (opal-A) was likely to have been an important source for quartz cements, although smectite-to-illite transformation may have contributed some. These mineral phases highlight that microscopic-scale diagenetic mobility of silica is important, even within mudstones lacking obvious sources of biogenic silica and is likely to be an important processes in a wide range of mudstones.
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Kilda, Linas, and Henrik Friis. "The key factors controlling reservoir quality of the Middle CambrianDeimena Group sandstone in West Lithuania." Bulletin of the Geological Society of Denmark 49 (December 31, 2002): 25–39. http://dx.doi.org/10.37570/bgsd-2003-49-03.
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Sandstones of the Middle Cambrian Deimena Group are commercially important as they make up the largest part of the hydrocarbon-bearing reservoir in 15 oil fields discovered in West Lithuania. However, the sandstones are characterised by a very complicated spatial distribution of reservoir quality. In order to better understand the distribution of reservoir properties and their controlling parameters, eighty-two sandstone samples from twenty-one boreholes were studied by means of thin section description, scanning electron microscopy, using backscattered and cathodoluminescence modes and clay fraction analyses. Generally, the sandstones are strongly cemented by quartz, resulting in almost total destruction of porosity but porous domains with preserved early stage quartz cement occur in a complex pattern. The close location of the early and late stage overgrowth types indicates that some sandstone parts were preserved from intense authigenic quartz precipitation. We believe that early carbonate cement was such an inhibitor. Detrital quartz grains in carbonate cemented domains are mostly free of authigenic quartz and as a rule show weakly compacted fabric as compared to the quartz cemented parts. Moreover, large secondary pores are located close to the carbonate cemented domains and indicate that some carbonate cement eventually dissolved. Apparently, the best reservoir properties within the generally strongly quartz cemented Deimena Groupsandstones are found in domains where dissolution of the early carbonate cement took place.
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Mitchell, Robert J., and David M. Stone. "Stability of reinforced cemented backfills." Canadian Geotechnical Journal 24, no. 2 (May 1, 1987): 189–97. http://dx.doi.org/10.1139/t87-024.
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Mining with backfill has been the subject of several international meetings in recent years and a considerable research effort is being applied to improve both mining economics and ore recovery by using backfill for ground support. Classified mill tailings sands are the most commonly used backfill material but these fine sands must be stabilized before full ore pillar recovery can be achieved. Normal portland cement is generally used for stabilization but the high cost of cement prohibits high cement usage. This paper considers the use of reinforcements in cemented fill to reduce the cement usage. It is concluded that strong cemented layers at typical spacings of about 3 m in a low cement content bulk fill can reinforce the fill and reduce the overall cement usage. Fibre reinforcements introduced into strong layers or into bulk fills are also known to be effective in reducing cement usage. Some development work is needed to produce the ideal type of anchored fibre in order to realize economic gains from fibre-reinforced fills. Key words: mining, backfilling, ground support, soil–cement, fibre reinforcement.
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Wei, Xiaoming, Lijie Guo, and Lei Zhang. "Study on the strength property and ratio parameter selection of waste rock cemented backfill." Journal of Mining Engineering and Research 2, no. 1 (June 10, 2021): 7–13. http://dx.doi.org/10.35624/jminer2020.01.02.
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When tailings are used for cemented backfill preparation, the extremely fine unclassified tailings may lead to slow consolidation and low strength of backfill material. Wasted rock as an additional filling aggregated was suggested to optimize the gradation composition of aggregate by scholars over the world. In this paper, the effect of waste rock addition, cement-tailing ratio and slurry concentration on strength and flow properties of waste rock cemented backfill were studied. The results indicate the strength of waste rock cemented backfill was significantly higher than that of unclassified tailings cemented backfill under same cement consumption, which the average strength improvements were 2.02MPa, 0.98MPa and 0.46MPa under cement-tailing ratio of 1:4, 1:8 and 1:10. With the increase of waste rock addition, the strength change of waste rock cemented backfill was less obvious, but the flow property (yield stress) of filling slurry was improved. Further analysis of the slurry stability illustrates that, with the increase of waste rock addition, the bleeding rate demonstrated a trend similar to that observed for the flow property, however, in an adverse manner. Overall, the optimal slurry concentration of 80% and waste rock addition of 40%～50% were determined. Based on the strength requirement, cement dosage was selected, which the cement-tailing ratio of top 10m and the bottom 10m was 1:8, the cement-tailing ratio of the centre stope was 1:10. The research findings can provide a reference for the ratio parameter determination of extremely fine unclassified tailings backfill of similar mines.
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Wang, Qi-Ang, Jia Zhang, and Jiandong Huang. "Simulation of the Compressive Strength of Cemented Tailing Backfill through the Use of Firefly Algorithm and Random Forest Model." Shock and Vibration 2021 (July 7, 2021): 1–8. http://dx.doi.org/10.1155/2021/5536998.
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Cemented tailings backfill is widely used in worldwide mining areas, and its development trend is increasing due to the technical and economic benefits. However, there is no reliable and simple machine learning model for the prediction of the compressive strength. In the present study, the research process to use artificial intelligence algorithms to predict the compressive strength of cemented tailing backfill was conducted, overcoming the shortcomings of traditional empirical formulas. Experimental tests to measure the compressive strength of cemented tailing backfill were conducted to construct the dataset for the machine learning. Five input parameters (tailing to cement ratio, percentage of fine tailings, cement type, curing time, and solid to water ratio) were considered for the design of the laboratory tests. The firefly algorithm (FA) was used to tune the random forest (RF) hyperparameters, and it was adopted to combine the RF model to improve the accuracy and efficiency for the prediction of the compressive strength of the cemented tailing backfill. By comparing the predicted and actual results, the reliability and accuracy of the prediction model proposed are confirmed. Tailing to cement ratio and curing time are the two most important parameters to the compressive strength of the cemented tailing backfill.
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Kuang, Guan-Ming, Tak Man Wong, Jun Wu, Jun Ouyang, Haihua Guo, Yapeng Zhou, Christian Fang, Frankie K. L. Leung, and William Lu. "Augmentation of a Locking Plate System Using Bioactive Bone Cement—Experiment in a Proximal Humeral Fracture Model." Geriatric Orthopaedic Surgery & Rehabilitation 9 (January 1, 2018): 215145931879531. http://dx.doi.org/10.1177/2151459318795312.
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Introduction: The purpose of this study was to test whether local filling of a novel strontium-containing hydroxyapatite (Sr-HA) bone cement can augment the fixation of a locking plate system in a cadaveric proximal humeral facture model. Materials and Methods: Twelve pairs of formalin-treated cadaveric humeri were used. One side in each pair was for cemented group, while the other side was for the control group. The bone mineral density (BMD) of the samples was tested. A 3-part facture model was created and then reduced and fixed by a locking plate system. In the cemented group, the most proximal 4 screw holes were filled with 0.5 mL bone cement. In the control group, the screw holes were not filled by cement. Locking screws were inserted in a standard manner before the cement hardened. X-ray was taken before all the specimens being subjected to mechanical study, in which 6 pairs were used for axial loading (varus bending) test, while other 6 pairs were used for axial rotational test. Results: There is no difference in BMD between the cemented side and the control side. The X-ray shows that the implant is in position. Cement filling was noted in the most proximal 4 screws in the cemented group. Better mechanical outcome was seen in the cemented groups, in terms of less maximal displacement per cycle and higher failure point and stiffness in varus bending test. However, no difference was found between the cemented group and the control group in the axial rotation test. Discussion: In similarity with the previous studies, our results showed better mechanical results in the cemented group. However, due to the limitations (e.g. sample size, fracture model, testing protocol, etc), we still cannot directly extrapolate current mechanical results to clinical practice at the present moment. Furthermore, it is still unknown whether better primary outcome may lead to better long-term results, even though the local release of strontium may enhance the local bone formation. Conclusion: The local filling of Sr-HA bone cement augments the fixation of the locking plate system in current proximal humeral fracture model.