Application Of Cement Research Articles

Life cycle assessment of the use of sewage sludge as Portland cement replacement

In this paper, we proposed an alternative thermal treatment of sewage sludge, aimed at its application in blended cements, which can reduce the energy demands and requires less technologically sophisticated processing. The life cycle assessment (LCA) was performed to quantify the environmental impact of the sewage sludge used as a partial cement replacement. The LCA was focused on the CO2 emission and energy consumption. The functional unit of 1 m3 of blended mortars composed of Portland cement CEM I 42.5, silica sand, and thermally treated sewage sludge, where the sludge was used as partial cement substitute in a dosage of 10, 20, and 30% by mass of cement, was analyzed. The positive effect of the use of sewage sludge as a partial cement replacement with respect to the energy consumption and GHG emission, considering the compressive strength of the analyzed composites, was quite apparent. The decrease of energy consumption necessary for the production of the analyzed blended binders was nearly 10% per each 10% of sewage sludge used as Portland cement replacement. The energy needed for the sludge thermal treatment at 700°C was 220 MJ/t. The emission of GHG related to the sludge thermal treatment was 40kg/t. The presented data were strongly affected by the applied distribution of electricity sources, with a high share of coal combustion plants.

White-light/tunable emissions in single-phased BaLa2Si3O10:Eu3+, Bi3+ phosphor for the simultaneous applications in white light-emitting diodes and luminous cement

In this work, we report the single-phased BaLa2Si3O10:Eu3+, Bi3+ phosphor with white-light/tunable emissions under UV excitations. We find the emissions of Bi3+-doped BaLa2Si3O10 samples are dependent on the excitation spectral wavelength, where exciting by the wavelength from 240 to 410 nm range can lead to the tunable Bi3+ emissions owing to the intensity change of three emission bands (i.e., 367 nm, 423 nm, and 516 nm). After co-doping the Eu3+ ions into Bi3+-doped BaLa2Si3O10, the energy transfer from Bi3+ to Eu3+ ions dominated by a dipole–quadrupole (d–q) interaction mechanism is proved. Typically, by exciting with 365 nm and varying the Eu3+ content, the tunable emissions from blue, white to red are observable in the BaLa2Si3O10:Eu3+, Bi3+. By coating the white BaLa2Si3O10:Eu3+, Bi3+ sample with a commercial 365-nm UV LED chip or mixing it with the cement, we not only achieve the white-light LEDs device with the desirable color rendering index (CRI) of 95, excellent luminescent efficiency of 80 lm/W, and good excellent color temperature (CT) of 4215 K at the CIE chromaticity of (0.338, 0.357), but also achieve the luminous cement.

Bioactive Glass-Based Endodontic Sealer as a Promising Root Canal Filling Material without Semisolid Core Materials.

Endodontic treatment for a tooth with damaged dental pulp aims to both prevent and cure apical periodontitis. If the tooth is re-infected as a result of a poorly obturated root canal, periapical periodontitis may set-in due to invading bacteria. To both avoid any re-infection and improve the success rate of endodontic retreatment, a treated root canal should be three-dimensionally obturated with a biocompatible filling material. Recently, bioactive glass, one of the bioceramics, is focused on the research area of biocompatible biomaterials for endodontics. Root canal sealers derived from bioactive glass-based have been developed and applied in clinical endodontic treatments. However, at present, there is little evidence about the patient outcomes, sealing mechanism, sealing ability, and removability of the sealers. Herein, we have developed a bioactive glass-based root canal sealer and provided evidence concerning its physicochemical properties, biocompatibility, sealing ability, and removability. We also review the classification of bioceramics and characteristics of bioactive glass. Additionally, we describe the application of bioactive glass to facilitate the development of a new root canal sealer. Furthermore, this review shows the potential application of bioactive glass-based cement as a root canal filling material in the absence of semisolid core material.

Does negative pressure intrusion cementing technique improve the cement penetration under the tibial component? A comparative retrospective study

Intramedullary suction cementing technique of the tibial component has the theoretical advantage to allow a deeper cement penetration trough the cancellous bone. The aim of this study is to compare the cement penetration under the tibial component between patients that underwent tibial component cementation with or without the use of intramedullary suction. Two-hundred-twenty-four patients underwent primary total knee arthroplasty (TKA) during the study period, One-hundred-twenty-two TKAs using intramedullary suction with negative pressure (55.4%), while one-hundred-two TKAs without intramedullary suction (44.6%). We found that the intra-operative suction during cement application increase the depth of cement penetration better than pulsed lavage alone.

The Photocatalytic Activity Of Cement In Reducing Air Pollutants

Air pollution is the major concern in the recent years because of causing imbalance to the ecosystem and also increases global warming and climate change. This paper, tries to investigate the applicability of photo catalytic cement in removing the pollutants under partially controlled and simpler experimental conditions such that it mimics the ideal state of its use, that is the natural open environment where it always is susceptible to complex physical and chemical interactions. It also gives an overview of the concentrations of the contaminants reduced not limiting to NOx residues alone, by employing Ion Chromatography instead of NOx analyzers.

Bond durability when applying phosphate ester monomer–containing primers vs. self-adhesive resin cements to zirconia: Evaluation after different aging conditions

PurposeThis study aimed to evaluate bond durability when applying 2 phosphate ester monomer-containing self-adhesive resin cements alone, versus a combination of phosphate ester monomer-containing primer conditioning plus 2 conventional resin cements requiring primers, to zirconia after different artificial aging methods. MethodsWe cemented air-abraded zirconia plates to composite resin cylinders with self-adhesive resin cements (MS; RU) alone or cemented them with traditional resin cements (ZRV; ZVN) after pre-conditioning with a zirconia primer. A shear bond strength (SBS) test were performed after subjecting them to 19 different aging conditions (n = 15) comprising 30,000× thermocycles, air storage at room temperature (RT), water storage at RT, or at 37 °C for 24 h, 1 week, 1, 3, 6, and 12 months. Zirconia powders mixed with zirconia primer or 2 self-adhesive resin cements were characterized by X-ray photoelectron spectroscopy. ResultsGroups MS and ZVN obtained the highest SBS after all of aging methods. SBS after 6 months of storage was similar to SBS after 24 h of storage, while both were higher than SBS after 1 year of storage. Water storage at 37 °C provided higher SBS than RT water storage did. We detected a Zr–O–P bond in both self-adhesive resin cement/zirconia powder mixtures. ConclusionsApplication of self-adhesive resin cements alone could be an alternative to pre-conditioning with a zirconia primer followed by the application of conventional resin cements. Formation of Zr–O–P bonds contributed to the bonding improvement of self-adhesive resin cements. Different aging conditions affected SBS values.

Application of expanding cements for sprayed concrete in tunnel construction

Introduction. The paper substantiates the actuality of the problem connected with obtaining efficient fine concretes possessing enhanced crack resistance, tightness, and duration for tunnel construction. This aim is pursued with the application of expansive cements (EC).
 Materials and methods. Various types of expansive agents were used in composition binders. Portland cement PTs 500 D0 was taken as the basic Portland cement. Studying hydration and structure formation processes during hardening of the ECs and EC-based concretes was executed utilizing a system of physicochemical methods. Assessment of construction and technical properties of the fine concretes based on composition binders was accomplished using standard research methods.
 Results. Analysis results are given for the effect of type and amount of the expansive agents on strength and volume deformation values of the concretes used in tunnel installation construction. Improvement of physical, mechanical, and technological properties and performance of sprayed concrete is shown. A general mechanism of influence of expansive additives (EA) on fine concrete properties is established. A classification of expansive cements for solving various tasks in tunnel installation construction is suggested.
 Conclusions. EA application efficiency is theoretically substantiated and experimentally proved for the case when the EA is used as an active agent in the composition binder for sprayed concrete in tunnel construction. General enhancement of technical indicators of concrete mixture and concretes is determined. EA classification is suggested for the different extent of hydrated EA expansion and various construction tasks. Replacement of standard Portland cement for an EC for underground structures concrete used in tunnel construction provides a significant increase in their maintainability.

Mechanical transformation of phyllite mineralogy toward its use as alkali-activated binder precursor

The mechanical activation of phyllite for use as an alkali-activated material was studied. Prolonged milling of phyllite resulted in reduced particle size and a structural reorganization of the material, leading to incremental increases in amorphous content, which further resulted in the improved reactivity of phyllite in an alkaline environment. Quantitative X-ray diffraction results showed that the phyllite consisted of quartz, muscovite, chamosite, albite, and X-ray amorphous phases. Among the crystalline phases, muscovite and chamosite underwent the most structural reorganization, leading to a more disordered structure due to prolonged and intensive milling. The structural reorganization was also established through Fourier-transform infrared spectroscopy. Dissolution tests in 6 M NaOH showed incremental increases in leached Al and Si elements with increased milling time. After geopolymerization of mechanically activated phyllite, calorimetric studies showed exothermic reactions, and a 28-day compressive strength of 25 MPa was achieved for paste samples cured at room temperature. This study ascertained the potential utilization of phyllite mineral waste in sustainable cement applications.

The Innovation of Glassfiber Reinforced Cement (GRC) Application in Buildings

One example of the innovation in building construction that is expansively used at present is Glassfiber Reinforced Cement (GRC). GRC is a cement product based on material mixed with fiberglass. GRC is one of the developments of concrete. This product easily and efficiently provides solutions to a variety of building designs. Additionally, its various forms can be applied to numerous types and functions of buildings. This research aimed to identify the suitability of GRC for several functions. The methods in this study employed a type of qualitative research, with data collection techniques in the form of observation and documentation in several examples of buildings that applied the GRC material innovation. Data analysis was obtained from observation related to GRC types, sizes, installation techniques, and functions in the building. Results showed that the GRC had various types, shapes, and sizes. It could be applied to the building exterior or interior. Each building used different GRC specifications tailored to meet needs and design of the building. GRC installation techniques could use the frame or without frames, adapted to the needs and types of GRC used

Graphene Oxide and Graphene Reinforced PMMA Bone Cements: Evaluation of Thermal Properties and Biocompatibility.

The incorporation of well-dispersed graphene oxide (GO) and graphene (G) has been demonstrated as a promising solution to improve the mechanical performance of polymethyl methacrylate (PMMA) bone cements in an attempt to enhance the long-term survival of the cemented orthopaedic implants. However, to move forward with the clinical application of graphene-based PMMA bone cements, it is necessary to ensure the incorporation of graphene-based powders do not negatively affect other fundamental properties (e.g., thermal properties and biocompatibility), which may compromise the clinical success of the implant. In this study, the effect of incorporating GO and G on thermal properties, biocompatibility, and antimicrobial activity of PMMA bone cement was investigated. Differential scanning calorimetry studies demonstrated that the extent of the polymerisation reaction, heat generation, thermal conductivity, or glass transition temperature were not significantly (p > 0.05) affected by the addition of the GO or G powders. The cell viability showed no significant difference (p > 0.05) in viability when MC3-T3 cells were exposed to the surface of G- or GO-PMMA bone cements in comparison to the control. In conclusion, this study demonstrated the incorporation of GO or G powder did not significantly influence the thermal properties or biocompatibility of PMMA bone cements, potentially allowing its clinical progression.

Calcium carbonate granulation in a fluidized-bed reactor: Kinetic, parametric and granule characterization analyses

The granulation of calcium carbonate (CaCO3) exhibited high industrial demand due to its wider application and importance in cement, paper, glass and steel manufacturing. This paper investigated the granulation kinetics of CaCO3 through the fluidized-bed homogeneous granulation (FBHG) process during the homogenous nucleation stage. The CaOH solution was used as source of Ca2+ reactant, while K2CO3 solution as source of CO32− precipitant. The mechanism followed the pseudo-second order kinetics. The calcium cation attracts the carbonate anion to form CaCO3 through a double displacement chemical reaction. The calcium-is-to-carbonate molar ratio ([Ca2+]/[CO32−]) was varied into 1.25 to 2.50, with constant values of pH = 10 ± 0.2, influent carbonate concentration = 10 mM and total influx flow rate = 60 mL min−1. The ideal [Ca2+]/[CO32−] condition was found to be at 1.50 that means the precipitation of CaCO3 grew and stayed inside the reactor. At the same condition, granules of diameter size of 1 mm to 2 mm were collected with a subrounded shape and smooth surface as shown by its surface morphology. The characterization analysis also verified the high purity of CaCO3-aragonite granules precipitated through the FBHG process.

CONSERVATIVE APPROACH TO DEEP CARIES LESIONS MANAGEMENT IN CHILDREN

The aim of the study was to systematize effective deep caries management methods in children in order to determine the indications for their use. The author used Google search engine to find articles and scientific publications published between 2006 and 2019.
 Reversible pulpitis is an indication for applying the methods preserving pulp vitality performed under aseptic and antiseptic conditions, provided the absence of decompensated form of caries and chronic somatic pathology. To prevent the accidental pulp exposure, it is better to use a partial excavation of the affected dentin followed by an indirect pulp capping. During direct pulp capping and pulpotomy the bleeding should be arrested within 3-5 min in primary teeth and within 5 min – in permanent ones. Direct pulp capping with MTA is indicated at the spot pulp exposure in permanent teeth, the use of this method in the primary teeth requires further research. Direct pulp capping with 5.25% sodium hypochlorite used as a hemostatic agent and MTA-type cement application under endodontic microscope or pulpotomy with MTA or Biodentine can be applied when treating reversible pulpitis in permanent teeth. In asymptomatic temporary teeth affected by reversible pulpitis full pulpotomy is adviced which is more effective with MTA.
 A promising direction in deep caries management research is direct and indirect pulp capping of primary teeth with Biodentine.

An Overview of Study on Basic Magnesium Sulfate Cement and Concrete in China (2012–2019)

In this review, investigations on the product of hydration, mechanical behavior, durability and application of basic magnesium sulfate cement (BMS) have been carried out in the past seven years in China. Structural characterization of 5·1·7 phase and hydration product of BMS are introduced in the first part of this paper. The second part gives the research on the basic properties of BMS: strength, setting time, and microstructure of BMS. The third part show the durability of the cement: water resistance, chloride penetration, ability of protecting reinforcing bars and carbonization. The last part is devoted to the production and application of BMS, which indicates that basic magnesium sulfate cement has wide application potential in the construction industry.

A potential need for surgeon consensus: Cementation techniques for total knee arthroplasty in orthopedic implant manufacturers' guidelines lack consistency.

Given recent concerns regarding the influence of different cements and implants on the rate of aseptic failures in total knee arthroplasty (TKA), we wondered if cementation technique could play a role. The primary aim of this review was to collect and compare the surgeon education materials from eight orthopedic implant manufacturers to evaluate the manufacturers' recommended cementation technique in TKA and identify if there was any consistency in these readily available guides as to the best practices of cementation of their implants. We reviewed contemporary surgeon education guidelines for all TKA systems available from eight manufacturers. Variables included: cement type, batches prepared, surface preparation prior to application, cleaning and/or drying the bone surface, mixing the cement, the waiting phase after the cement has been mixed prior to application, pressurizing the cement, location of cement application, and the curing time. Data were recorded and organized for qualitative comparisons. We identified a total of 43 guides covering 38 implants from eight different manufacturers. There were 41 surgical technique guides and two general brochures regarding cementation techniques available from the manufacturers. Even within the manufacturers' own guidelines for the different implants, there was a wide variety of differing guidelines on many aspects of the cementation technique. There is clearly no consensus for a preferred cementation technique both within and among manufacturers' surgeon education materials regarding tibial baseplate cementation during TKA. Efforts may be needed to identify a best-practice cementation technique in an effort to reduce the number of TKA failures associated with aseptic loosening.

Cementing technique for primary knee arthroplasty: a scoping review

Background and purpose — The optimal cementing technique for primary total knee arthroplasty (TKA) remains unclear. We therefore performed a scoping review based on available studies regarding cementation technique in primary TKA and unicondylar knee arthroplasty (UKA).Patients and methods — A search in 3 databases identified 1,554 studies. The inclusion criteria were literature that studied cementing technique in primary TKA or UKA. This included cement application methods, full or surface cementing, applying cement to the bone and/or prosthesis, stabilization of the implant during curing phase, bone irrigation technique, drilling holes in the bone, use of suction, and the timing of cementation. 57 studies met the inclusion criteria.Results — The evidence was unanimously in favor of pulsatile lavage irrigation, drying the bone, and drilling holes into the tibia during a TKA. All studies concerning suction recommended it during TKA cementation. 7 out of 11 studies favored the use of a cement gun and no studies showed that finger packing was statistically significantly better than using a cement gun. There is evidence that full cementation should be used if metal-backed tibial components are used. Applying the cement to both implant and bone seems to give better cement penetration.Interpretation — There are still many knowledge gaps regarding cementing technique in primary TKA. There seems to be sufficient evidence to recommend pulsatile lavage irrigation of the bone, drilling multiple holes, and drying the bone before cementing and implant insertion, and applying cement to both implant and on the bone.

Bioinspired and biomineralized magnesium oxychloride cement with enhanced compressive strength and water resistance

High CO2 emissions during the production process of ordinary Portland cement (OPC) promoted greener-cement development, wherein the application of magnesium oxychloride cement (MOC) can add value to waste in potash industry and reduce environmental hazards. However, its application was restricted by its inferior water resistance. It’s a challenge to remarkably increase both the compressive strength and water resistance of MOC. Herein, we demonstrate that cornstarch/sodium polyacrylate (PAAS) MOC composites exhibit increased compressive strength and water resistance. Moreover, the biomineralization process encourages the growth and alignment of phase 5 crystals by a cornstarch template with hydroxyl groups, thus enhancing the compressive strength of MOC. The chelation of magnesium ions and the transformation of phase 5 crystal structure by PAAS can significantly enhance the water resistance of MOC. This composite exhibits a 21.0% increase in compressive strength, and the softening coefficient is also increased from 0.48 to 0.81 in comparison with unmodified-MOC. Meanwhile, the hydrogen bonds between cornstarch and elemental Cl obviously decrease the efflorescence phenomena of the MOC. This MOC composite with a markedly increased compressive strength and water resistance, which was prepared by a facile and green method, may have potential applications in building development and the replacement of OPC.

P22. Lumbar intervertebral spacer with cement augmentation of endplates and integrated screws as a fixation device in an osteoporotic model: an in vitro kinematic and load-to-failure study

BACKGROUND CONTEXT Integrated LLIF stabilizes the spine and avoids complications related to posterior fixation. However, contraindications such as low bone mineral density (BMD) and older age can increase risk of subsidence. Traditional cement augmentation through cannulated pedicle screws enhances pedicle fixation and cage-endplate interface, yet may be disadvantageous due to associated paraspinal dissection, blood loss, and iatrogenic infection. Nevertheless, cement augmentation may be sufficient in preventing subsidence of stand-alone LLIF reconstructions in elderly patients. The lateral application of cement with integrated LLIF fixation has been introduced and requires kinematic and failure characterizations. PURPOSE To evaluate kinematic and load-to-failure properties of a novel cement augmentation technique with an integrated lateral lumbar interbody fusion (LLIF) device, both alone and with unilateral pedicle fixation, in comparison with bilateral pedicle screws and non-integrated LLIF (BPS+S). STUDY DESIGN/SETTING In vitrohuman cadaveric study. PATIENT SAMPLE 12 cadaveric specimens. OUTCOME MEASURES Range of motion (ROM) and ultimate load to failure. METHODS Twelve specimens (L3–S1) underwent discectomy (L4–L5). Specimens were separated into 3 groups: (1) BPS+S, (2) polymethylmethacrylate (PMMA), integrated LLIF, and unilateral pedicle screws. (PMMA+UPS+iS), and (3) PMMA with iSA (PMMA+iSA). Before LLIF insertion, a vertebroplasty needle inserted 3mm deep from the endplate at the vertical midline of the vertebral body (VB). The needle was repeatedly inserted through the cancellous bone, creating a cavity deep to the endplate. PMMA (3cc) was injected into the cavity, limited to approximately 25% of the operative endplates, followed by insertion of the LLIF device. After cement curing, flexion-extension, lateral bending and axial rotation were applied. Finally, a compressive load was applied to the segments until failure to assess spacer-endplate strength. RESULTS No significant differences in BMD T-scores between BPS+S (-1.9±0.7), PMMA+UPS+iS (-1.8±0.5), and PMMA+iS (-1.8±0.7) groups were observed (P = 0.992). Operative constructs significantly reduced motion relative to intact specimens in all motion planes (P 0.05). PMMA+UPS+iS provided the greatest resistance to failure (2290 N), followed by PMMA+iSA (1970 N), and lastly, BPS+S (1390 N); no significant differences were observed (P > 0.05). CONCLUSIONS A novel technique of vertebral endplate cement augmentation via the lateral approach with an integrated interbody device for osteoporotic patients who would otherwise require posterior fixation to reduce likelihood of subsidence is proposed. The integrated lateral interbody spacer with vertebral endplate cement augmentation, both prior to and following unilateral pedicle fixation, was biomechanically equivalent to traditional anteroposterior fixation with non-integrated LLIF. The integrated device with cement augmentation moderately improved spacer-endplate interface compared to BPS+S in an osteoporotic model, increasing failure loads compared by 41.7%; the addition of unilateral fixation further increased resistance to failure (64.7%). Overall, results suggest integrated LLIF with cement may be a viable alternative in the presence of osteoporosis. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.

HF etching of CAD/CAM materials: influence of HF concentration and etching time on shear bond strength

BackgroundThe required pretreatment of CAD/CAM ceramic materials before resin composite cement application varies among studies. The aim of the present study was to evaluate the effect of hydrofluoric acid concentration and etching time on the shear bond strength (SBS) of two adhesive and two self-adhesive resin composite cements to different CAD/CAM ceramic materials.MethodsSBS of two adhesive (Panavia V5, Kuraray, [PV5]; Vita Adiva F-Cem, Vita Zahnfabrik, [VAF]) and two self-adhesive (RelyX Unicem 2 Automix, 3 M Espe, [RUN]; Vita Adiva S-Cem, Vita, [VAS]) cements to four different CAD/CAM materials (Vitablocs Mark II, Vita, [VM]; Vita Enamic, Vita, [VE]; e.max CAD, Ivoclar Vivadent, [EC]; Vita Suprinity PC, Vita, [VS]) was measured. The effect of the surface pretreatment by using two different hydrofluoric acid products (HF5% Vita Ceramics Etch, Vita and HF9% buffered, Ultradent Porcelain Etch, Ultradent Products) were assessed at etching times of 0 s, 5 s, 15 s, 30s and 60s for each cement and restorative material combination (n = 10 per group, total n = 1440).ResultsSignificant effects were found for the etching time and cement for all materials with highest shear bond strength for etching times of 60s = 30s = 15 s ≥ 5 s > 0 s and for RUN>PV5 = VAF > VAS (p < 0.05). Etching with HF5% for 5 s to 15 s resulted in higher SBS values, while no differences were observed between HF5% and HF9% buffered when the substrates were etched for 30s to 60s (p < 0.05).ConclusionsWithin the limitations of this study the recommended surface pretreatment of silicate ceramics is HF etching with concentrations of 5% or 9% for 15 s to 60s to achieve highest shear bond strength while the glassy matrix is sufficiently dissolved. The tested resin composite cements can be applied with all tested materials and suggested for clinical application.

Effect of universal adhesives on microtensile bond strength to hybrid ceramic

BackgroundThe aim of this study was to evaluate the effect of universal adhesives (UA) and silane on the microtensile bond strength (μTBS) of resin cement to a hybrid ceramic Vita Enamic (VE).MethodsVE specimens were acid etched using hydrofluoric acid (HF) and were assigned to three groups (n = 10) based on the applied bonding technique. In group 1 (S), a silane-based primer was used as a surface treatment prior to the application of a resin cement (Variolink Esthetic DC). In group 2, a silane-containing UA, Clearfil Universal Bond (CUB) was used for the surface treatment, and in group 3, A silane-free UA, Tetric N-Bond Universal (TNU) was used for surface treatment. Resin cement build-ups were prepared. The bonded specimens were sectioned into resin-ceramic beams. Half of the beams of each group were stored for 24 h at 37 °C and the other half were subjected to a thermo-cycling aging. The microtensile bond strength (μTBS) was measured at a crosshead speed of 0.5 mm/min. Failure modes were assessed accordingly. Data were analyzed using a) two-way analysis of variance ANOVA followed by one-way ANOVA and Tukey tests between groups and b) independent t-test to detect differences (α = 0.05) for each group. The surface topographies of the ceramic surface were evaluated using scanning electron microscopy.ResultsThe results showed that silane-based primer (S) application resulted in significantly higher (p < 0.05) μTBS values after 24 h and after thermocycling compared to both silane-containing UA (CUB) and silane-free UA (TNU). The μTBS values of all groups were significantly reduced after thermocycling. No statistically significant difference was observed between the μTBS of CUB and TNU after 24 h. However, TNU showed significantly higher μTBS after thermocycling. Different failure modes were observed, and adhesive failure was the most common in all groups. Marked surface topographic changes were observed following HF etching.ConclusionIt is concluded that, the UAs tested cannot be recommended as substitutes to the silanization of Hybrid ceramic.

Evaluation of Bond Strength of Aesthetic Type of Posts at Different Regions of Root Canal after Application of Adhesive Resin Cement.

AIM:This study aimed to evaluate the bond strength between esthetic posts and dentin at different regions of the root canal in passive mode or push-out active mode.METHODS:Twenty extracted human bicuspid single canal teeth were used in this study. Teeth were sectioned below the cement-enamel junction. The roots of teeth were endodontically treated. Glass fibre posts (Glassix plus, Harald Nordin SA, Switzerland) and zirconia posts (Zirix, Harald Nordin) were then adhesively luted with total-etch (Variolink N, Ivoclar Vivadent, Schaan, Liechtenstein) and self-adhesive (Multilink Speed, Ivoclar Vivadent) resin cement. The roots were divided into two main groups of 10 samples each, according to the type of post used. Each group subdivided into 2 subgroups of 5 samples each, according to the type of cement used. The specimens were transversally sectioned into three slices of 2 mm thickness to perform the push-out test. The push-out tests were performed at crosshead-speed, 0.5 mm/min). Failure modes were evaluated using a scanning electron microscope at magnification (x 150).RESULTS:The results revealed that push-out bond strengths were significantly affected by the type of luting agent and the type of post (P ≤ 0 .05). The mean push-out bond strength values for fibre post were significantly higher than those for zirconia post independent of the luting strategy used. The score values of total-etch adhesive resin cement were higher than those for self-adhesive resin cement irrespective of other variables. Regarding the effect of the root segment on push-out bond strength, results revealed that bond strength decreased from the coronal to the apical section. The cement-dentin interface found to be the weakest part of the root-cement-post unit.CONCLUSION:Glass fibre posts revealed better results in all root third when they adhesively luted with total-etch or self-etch adhesive resin cement and provided significantly increased bond strength compared to the zirconia posts.