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Results for “Flexural Strength”

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12 recordsLinked to original sources

PubMed1977

The modulus of elasticity and flexural strength of some acrylic bone cements.

The modulus of elasticity and flexural strength were measured for three bone cements, CMW Bone Cement, Surgical Simplex, and Palacos R. with various additions and prepared as in actual use. A distinct afterpolymerization was demonstrated in all three brands. The addition of blood lowered the E-modulus wheras radio-opaque media seemed to render them somewhat stiffer. The rupture values demonstrated the inhomogeneity of the final product in all three brands. The possible clinical significance of the findings is discussed.

Bone Cements↗

PubMed2026

Clinical performance of two lithium disilicate CAD/CAM materials in posterior Class II inlay restorations: A 48-month randomised split-mouth clinical trial.

OBJECTIVES: To compare the clinical performance of Amber Mill (AM) and IPS e.max CAD (EM) lithium disilicate computer-aided design/computer-aided manufacturing (CAD/CAM) materials in posterior Class II inlay restorations and characterise their baseline properties. METHODS: Thirty-four adults received paired AM and EM posterior Class II inlays (68 restorations) in a triple-blind randomised split-mouth trial followed for 48 months. Restorations were evaluated at baseline and annually using revised World Dental Federation (FDI) criteria, with fracture and retention as the primary endpoint. Baseline characterisation included flexural strength, shear bond strength, translucency parameter, and scanning electron microscopy. McNemar, Wilcoxon signed-rank, Friedman, one-way analysis of variance, Tukey post hoc, and inter-rater agreement analyses were used. RESULTS: At 48 months, 18 paired participants were available for primary analysis. Failures occurred in 2 of 18 AM restorations and in 3 of 18 EM restorations, corresponding to success rates of 88.9% and 83.3%, respectively, with no significant between-material difference (McNemar p = 1.000). No catastrophic bulk ceramic fracture was observed. Secondary FDI scores remained mostly within the clinically acceptable range; marginal staining deteriorated over time in both groups (p < .001) without significant between-material differences. Baseline material testing showed significant material- and translucency-dependent differences in flexural strength, shear bond strength, and translucency. CONCLUSIONS: Within the limitations of the 48-month follow-up and the tested Class II inlay indication, AM showed clinical performance comparable to EM. Observed clinical complications were related to retention or marginal/interface behaviour. CLINICAL SIGNIFICANCE: For posterior Class II lithium disilicate CAD/CAM inlays, medium-term complications were mainly retention/interface-related, suggesting adhesive-interface durability may be as important as baseline ceramic strength.

Humans↗

PubMed2026

Fused Deposition Modeling (FDM) of polyether-ether-ketone (PEEK) dental implants: A systematic review of the effect of printing parameters on mechanical behaviour and surface quality.

PURPOSE: This systematic review evaluated how FDM printing parameters influence mechanical behaviour and surface characteristics of 3D-printed PEEK and identified parameter combinations linked to the most favourable mechanical performance and surface quality. MATERIALS AND METHODS: An electronic search was conducted in: MEDLINE (Ovid), PubMed, Embase, Web of Science, Scopus, and Compendex (last update: January 2025). Studies that evaluated the effect of FDM printing parameters on mechanical and surface properties of PEEK were included. Outcomes comprised compressive, tensile, and flexural strengths, elastic modulus, fracture toughness, surface hardness, roughness, and wettability. RESULTS: Of 4005 reports screened, 54 manuscripts were included. 92.6% (n = 50) of articles showed low risk-of-bias, while 7.4% (n = 4) showed medium risk-of-bias. Tensile strength was the most investigated mechanical parameter (78%), followed by elastic modulus (41%), flexural strength (30%), compressive strength (20%), and fracture toughness (6%). Surface roughness was the most evaluated surface property (30%), followed by hardness (17%) and wettability (6%). Across studies, higher printing temperatures, lower printing speed, thinner layer thickness, and maximum infill ratio in a horizontal printing orientation were associated with higher strengths, less warpage, increased accuracy, and improved surface quality. CONCLUSION: Specific combinations of FDM printing parameters can significantly improve the mechanical and surface properties of PEEK. However, it is difficult to meet all the optimal conditions simultaneously. Thus, balancing between different parameters must be considered in practical production.

Benzophenones↗

PubMed1978

Carbon fiber-reinforced carbon as a potential implant material.

A carbon fiber-reinforced carbon is being evaluated as a promising implant material. In a unidirectional composite, high strengths (1200 MN/m2 longitudinal flexural strength) and high modulus (140 GN/m2 flexural modulus) may be obtained with an interlaminar shear strength of 18 MN/m2. Alternatively, layers of fibers may be laid in two directions to give more isotopic properties. The compatibility of the material with bone has been studied by implanting specimens in holes drilled in rat femora. For a period of up to 8 weeks, a thin layer of fibrous tissue bridged the gap between bone and implant; but this tissue mineralizes and by 10 weeks, bone can be observed adjacent to the implant, giving firm fixation. Potential applications include endosseous dental implants where a greater strength in the neck than that provided by unreinforced carbon would be advantageous.

Animals↗

PubMed1978

Strength of a dense alumina ceramic after aging in vitro.

Rods of dense alumina ceramic were aged in Ringer's solution for time periods up to 12 weeks, with half of the rods being aged while mechanically stressed. Pyrex-type glass rods were similarly tested for comparison purposes. No reduction in flexural strength was observed in dense alumina rods after aging, providing no permeation of the solution into the ceramic occurred. However, a marked reduction in flexural strength was experienced by alumina rods, nominally dense and nonporous, into which some permeation of the saline solution was observed after aging; the largest reduction in strength occurred in such rods aged while mechanically stressed. The results indicate the importance and advantage of using densely sintered alumina ceramics as implants for optimum structural performance over an extended time period.

Aluminum↗

PubMed1979

[Comparative materials science studies of Evicrol plastic filling material].

The water absorption of Evicrol, its hardness, flexural strength and abrasion resistance were measured and compared with the values found for Adaptic and those for Kallocryl A as a non-filled polymethyl methacrylate plastic. The flexural strength and the abrasion resistance of Evicrol amount to those of Adaptic. The hardness of Evicrol falls also short of that of Adaptic. On the contrary, Evicrol behaves quite differently under water. It was found that the amound of water absorbed by Evicrol is some 3-fold greater than that absorbed by Adaptic, and that saturation is reached considerably slower.

Absorption↗

PubMed1976

Mechanical properties of bone cements containing large doses of antibiotic powders.

The addition of up to 10 g gentamicin sulfate antibiotic powder to 60 g units of Simplex-P acrylic bone cement caused gradual, proportional decreases in the bulk muchanical properties of compressive and diametral tensile strengths. Water leaching of the antibiotic from the cement did not significnatly decrease these strenghts. Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) showed the antibiotic to reside in the acrylic matrix as discrete particles not usually associated with internal porosity. The surface-sensitive flexural strength of a proprietary bone cement was lowered immediately by small quantities of antibiotic powder, and continued to decrease as doses of up to 10 g/unit were admixed. Water leaching caused channeling as the antibiotic was removed from the surface, but it did not create further changes in flexural strength.

Bone Cements↗

PubMed1975

Studies on mechanical properties of denture base material laminated with organic fiber reinforced plastics. Part I. Basic consideration of hybrid construction.

Acrylic resin is widely used as a denture base material, but the upper complete denture fails often during use. Therefore, the denture base made from acrylic resin should be reinforced in some way. Therefore, as a new method of reinforcement on the denture base, the authors devised a method to improve the strength and rigidity by laminating the palatal surface of the denture base with an organic fiber reinforced plastic, the so-called canapé construction. In this paper, as the basic experiment, the flexural strength, fatigue strength and the modulus of elasticity in bending of reinforced acrylic resin by the canapé construction were investigated. As the results, the flexural and fatigue strength are improved respectively 160% and 130% compared to the denture base acrylic resin. And the modulus of elasticity in bending is improved 80%. Therefore, it is considered that this new combination of materials using the canapé construction might be sufficiently applied to the denture base.

Acrylic Resins↗

PubMed1978

Bending deformation studies of orthodontic wires.

Bending deformation has been measured for orthodontic wires ranging in diameter from .010 to .051 inch. Results establish a revised expression for Young's modulus and show that either the stiffness tester or the torque meter will yield essentially the same measured values of bending properties. The dependence of test span length in determining Young's modulus and flexural yield strength is discussed.

Chemical Phenomena↗

PubMed1979

Measurement of bending deformation for small diameter orthodontic wires.

The stiffness tester and torque meter were found to yield nearly the same measurements of bending deformation for orthodontic wires as small as .007 inch diameter, provided the different bending apparatus are calibrated to each other. Although frictional losses in the test apparatus did not appear to be significant, the test span length does significantly affect measured values of Young's modulus and flexural yield strength, in a manner similar to that previously found for larger-diameter wires.

Chromium Alloys↗

PubMed1977

A flexural method for evaluation of metal-ceramic bond strengths.

A test technique is presented for evaluating metal-ceramic bond strengths. The test piece consists of a four-point loaded metal beam with porcelain bonded to the central tension side of the beam. The test produced failures at predictable locations and was able to differentiate between metal surface treatments.

Dental Alloys↗

PubMed1978

Fatigue-induced damage in glutaraldehyde-preserved heart valve tissue.

Glutaraldehyde-preserved porcine mitral leaflet tissue has been subjected to extended accelerated fatigue loading in Ringer's solution containing 0.15% glutaraldehyde. Five tissue test pieces were subjected to cyclic tensile stresses of 50 and 200 Gm. per square millimeter and to 300 million to 800 million accumulated fatigue cycles. Tissue disruption occurred in each of the fatigued test pieces. Tensile loading, apart from reducing the acuteness of the collagen waveform and thereby decreasing tissue compliance, does not contribute significantly to the disruption process nor its rate of occurrence. Compressive flexure occurring during the unloading half of the fatigue cycle, however, does induce damage in the tissue. Mechanisms involved in the disruptive processes have been identified by conducting simultaneous morphologic and stress/strain observations on both the fatigued and unfatigued tissues in their wet functional condition. This vulnerability of the preserved tissue to compressive flexure could well affect the long-term durability of the glutaraldehyde-preserved heterograft valve, and this possibility is discussed in relation to the clinical use of these valves.

Animals↗