Fatigue strength of bilayer yttria-stabilized zirconia after low-temperature degradation.

This study examined the impact of interfacial interactions on bilayer yttria-stabilized zirconia (YSZ) used in dental restorations. In-house bilayer structures of 3YSZ and 5YSZ composition underwent hydrothermal degradation to compare the properties of control and low-temperature degradation (LTD) treated groups. Biaxial flexural strength via piston-on-three-balls, staircase fatigue strength over 10 cycles at 15 Hz, phase characterization and quantification through XRD and Rietveld refinement, and fractography were conducted.

New Insights Into Application Relevant Properties of Cu-Doped Brushite Cements.

Doping of brushite cements with metal ions can entail many positive effects on biological and physicochemical properties. Cu ions are known to exhibit antibacterial properties and can additionally have different positive effects on cells as trace elements, whereas high Cu concentrations are cytotoxic. For therapeutical applications of bone cement, a combination of good biocompatibility and sufficient mechanical properties is required.

Ultrafast and Reproducible Synthesis of Tailor-Made Octacalcium Phosphate.

Octacalcium phosphate (OCP) has excellent bone formation ability and a good resorption rate as compared to the commercial bone substitutes [, Bio-Oss (Geistlich Pharma AG) and MBCP+ (Biomatlante)], as well as synthesized biomaterials (hydroxyapatite and tricalcium phosphate). The synthesis approach to obtain phase-pure OCP possesses a great challenge due to its complex reaction mechanism and narrow synthesis window. Thus, the current study aimed to overcome the synthesis challenges and to define the precise reaction conditions required for controllable and reproducible synthesis of OCP.

Glass science behind lithium silicate glass-ceramics.

Objectives: Lithium silicate-based glass ceramics have evolved as a paramount restorative material in restorative and prosthetic dentistry, exhibiting outstanding esthetic and mechanical performance. Along with subtractive machining techniques, this material class has conquered the market and satisfied the patients' needs for a long-lasting, excellent, and metal-free alternative for single tooth replacements and even smaller bridgework. Despite the popularity, not much is known about the material chemistry, microstructure and terminal behaviour.

On the assignment of quartz-like LiAlSiO - SiO solid solutions in dental lithium silicate glass-ceramics: Virgilite, high quartz, low quartz or stuffed quartz derivatives?

Objectives: Here we aim to provide a background on X-Ray Diffraction analysis of quartz-like crystal structures with varying amounts of Al and Li substitution, existing confusions on their nomenclature and its implications for novel lithium silicate glass-ceramics.

Methods: We reviewed the literature dealing with modifications of the quartz crystal structure and their stuffed LiAlSiO derivates, LiAlSiO - SiO solid solutions, the terminology of such phases and criteria used to define the structure known as virgilite. Based on this information, we attempted to allocate the quartz-like phases found in CEREC Tessera, Initial LiSi Block and Amber® Mill in the range of LiAlO - SiO solid solutions.

Scavenging of bacteria or bacterial products by magnetic particles functionalized with a broad-spectrum pathogen recognition receptor motif offers diagnostic and therapeutic applications.

Sepsis is a dysregulated host response of severe bloodstream infections, and given its frequency of occurrence and high mortality rate, therapeutic improvements are imperative. A reliable biomimetic strategy for the targeting and separation of bacterial pathogens in bloodstream infections involves the use of the broad-spectrum binding motif of human GP-340, a pattern-recognition receptor of the scavenger receptor cysteine rich (SRCR) superfamily that is expressed on epithelial surfaces but not found in blood. Here we show that these peptides, when conjugated to superparamagnetic iron oxide nanoparticles (SPIONs), can separate various bacterial endotoxins and intact microbes (E.

Grasping the Lithium hype: Insights into modern dental Lithium Silicate glass-ceramics.

Objectives: Lithium-based glass-ceramics are currently dominating the landscape of dental restorative ceramic materials, with new products taking the market by storm in the last years. Though, the difference among all these new and old products is not readily accessible for the practitioner, who faces the dilemma of reaching a blind choice or trusting manufacturers' marketing brochures. To add confusion, new compositions tend to wear material terminologies inherited from vanguard dental lithium disilicates, disregarding accuracy.

Toughening by revitrification of LiSiO crystals in Obsidian® dental glass-ceramic.

As a predominantly lithium-metasilicate-containing glass-ceramic, Obsidian® (Glidewell Laboratories, USA) has a peculiar composition and microstructure among other dental lithium silicates, warranting an evaluation of the crystallization process to establish relationships between microstructural evolution and mechanical properties. Blocks of the pre-crystallized material were processed into slices measuring 12 × 12 × 1.5 mm and subjected to the mandatory crystallization firing by interruption the heating ramp at temperatures between 700 °C and 820 °C (dwell time between 0 min and 10 min).

Synthesis, Characterization, Antibacterial Properties, and In Vitro Studies of Selenium and Strontium Co-Substituted Hydroxyapatite.

In this study, as a measure to enhance the antimicrobial activity of biomaterials, the selenium ions have been substituted into hydroxyapatite (HA) at different concentration levels. To balance the potential cytotoxic effects of selenite ions (SeO) in HA, strontium (Sr) was co-substituted at the same concentration. Selenium and strontium-substituted hydroxyapatites (Se-Sr-HA) at equal molar ratios of Se/(Se + P) and Sr/(Sr + Ca) at ( = 0, 0.

Effect of sintering parameters on phase evolution and strength of dental lithium silicate glass-ceramics.

Objective: With the establishment of CAD/CAM technology, competing lithium silicate based formulations have been introduced for clinical use, but little is known about their phase composition. Here we investigate a commercially available SiO-AlO-KO-LiO-PO-ZrO system to evaluate the crystal phase evolution during the second heat treatment by changing the main crystallization parameters.

Methods: With a focus on the final stage of crystallization, we characterized the dimensional changes in the crystallographic structure of the residual LiSiO and the lithium orthophosphate (LiPO) phases with variations in crystallization parameters, i.

Setting Mechanism of a CDHA Forming α-TCP Cement Modified with Sodium Phytate for Improved Injectability.

A calcium deficient hydroxyapatite (CDHA) forming cement with a bimodal grain size distribution, composed of α-TCP and fine grained CDHA at a weight ratio of 9:1, was modified by the addition of sodium phytate (IP6) in variable amounts ranging from 0.25 to 2 wt.%, related to the powder content.

Phase-specific bioactivity and altered Ostwald ripening pathways of calcium carbonate polymorphs in simulated body fluid.

Calcium carbonate is an abundant biomineral, and already archeological records demonstrate its bioactivity and applicability for osseo-integrative implants. Its solubility, which is generally higher than those of calcium phosphates, depends on its polymorph turning calcium carbonate into a promising biomaterial with tunable bioresorption rate. However, the phase-dependent bioactivity of calcium carbonate, , its osteoconductivity, is still insufficiently characterized.

Crack-healing during two-stage crystallization of biomedical lithium (di)silicate glass-ceramics.

Objective: The study is aimed to evaluate the two single commercially available two-step lithium-(di)silicate systems by analyzing their parent glass composition and studying the quantitative crystalline and glass phase evolution during the second stage heat-treatment. The mechanical repercussions of the crystallization firing were evaluated using strength and fracture toughness tests.

Methods: XRF and ICP-OES were used to determine the oxide composition of the parent glasses in Suprinity PC (Vita Zahnfabrik) and IPS e.

Hydration mechanism of a calcium phosphate cement modified with phytic acid.

Calcium phosphate cements composed of β-tricalcium phosphate (β-TCP) and phosphoric acid were modified by addition of 5, 10, 12.5, 15 and 20 wt% phytic acid (IP6) related to the β-TCP content and compared to a reference containing 0.5 M citric acid monohydrate solution as setting regulator.

Hydration mechanism of partially amorphized β-tricalcium phosphate.

Unlabelled: Calcium phosphate cements (CPCs) are applied as bone cements due to their excellent biocompatibility. In the present study, the quantitative phase content development during hydration of partially amorphized β-tricalcium phosphate (β-TCP) within the first 24h was investigated by in-situ X-ray diffraction (XRD) combined with the G-factor method, an external standard method. The quantity of amorphous phase (ATCP) in the powders was determined by the G-factor method.

Reaction kinetics of dual setting α-tricalcium phosphate cements.

Addition of ductile polymers to calcium-deficient hydroxyapatite (CDHA)-forming bone cements based on α-tricalcium phosphate (α-TCP) is a promising approach to improve the mechanical performance of α-TCP cements and extend their application to load-bearing defects, which is else impeded by the brittleness of the hardened cement. One suitable polymer is poly-(2-hydroxyethylmethacrylate) (p-HEMA), which forms during cement setting by radical polymerisation of the monomer. In this study the hydration kinetics and the mechanical performance of α-TCP cements modified with addition of different HEMA concentrations (0-50 wt% in the cement liquid) was investigated by quantitative in situ XRD and four-point bending tests.

Calorimetry investigations of milled α-tricalcium phosphate (α-TCP) powders to determine the formation enthalpies of α-TCP and X-ray amorphous tricalcium phosphate.

One α-tricalcium phosphate (α-TCP) powder was either calcined at 500°C to obtain fully crystalline α-TCP or milled for different durations to obtain α-TCP powders containing various amounts of X-ray amorphous tricalcium phosphate (ATCP). These powders containing between 0 and 71wt.% ATCP and up to 2.

Effect of amorphous phases during the hydraulic conversion of α-TCP into calcium-deficient hydroxyapatite.

Powders of α-tricalcium phosphate (α-TCP), which readily react with water to form calcium-deficient hydroxyapatite (CDHA), are frequently used in bone cements. As, for clinical applications, it is important to adjust the setting reaction of the cements to a reasonable reaction time, exact knowledge of the hydration mechanism is essential. It is known that prolonged milling results in partial amorphization of α-TCP powders and that dissolution of the amorphous phase significantly accelerates the hydration, but it is not clear yet when the amorphous phase reacts in comparison to the crystalline α-TCP.