Crack propagation and toughening mechanism of bilayered short-fiber reinforced resin composite structure -Evaluation up to six months storage in water.

Clinically relevant parameters, such as stress intensity factor of bilayered resin composite structure with short fiber base and its stability over time, has yet to be investigated. This study investigated the stress intensity factor of pre-cracked bilayered specimens composed of short fiber resin composite base (SFC) and particulate filler resin composite (PFC) as veneering layer, with a crack located in the PFC layer, 0.5 mm away from the PFC-SFC interface.

Push-Out Force and Microleakage of Screw Access Hole Filling Materials in Monolithic Zirconia Implant Crowns.

Purpose: To test the push-out force and marginal leakage of different screw hole-sealing methods in monolithic zirconia implant crowns.

Materials And Methods: Ninety monolithic zirconia (Prettau, Zirkonzahn) specimens were milled with two different screw access hole designs: conventional smooth hole or threaded screw hole (for group PMMA-SC), and divided into five groups (n = 18) according to filling method: unbonded composite (UBC); bonded composite (BC); airborne-particle abrasion of screw hole and unbonded composite (ABR-UBC); airborne-particle abrasion of screw hole and bonded composite (ABR-BC); and PMMA screw plugs (PMMA-SC). Twelve specimens per group were subjected to static push-out force with a universal testing machine.

Evaluation of New Hollow Sleeve Composites for Direct Post-Core Construction.

The preset shape and diameter of a prefabricated FRC post rarely follows the anatomy of the root canal. To solve this problem, a new hollow sleeve composite (HSC) system for post-core construction was developed and characterized. A woven fiber was impregnated with two types of resins: Bis-GMA or PMMA, and rolled into cylinders with outer diameter of 2 mm and two different inner diameters, namely 1.

3D-Printed vs. Heat-Polymerizing and Autopolymerizing Denture Base Acrylic Resins.

The aim of this work was to investigate the effect of two post-curing methods on the mechanical properties of a 3D-printed denture base material. Additionally, to compare the mechanical properties of that 3D-printed material with those of conventional autopolymerizing and a heat-cured denture base material. A resin for 3D-printing denture base (Imprimo), a heat-polymerizing acrylic resin (Paladon 65), and an autopolymerizing acrylic resin (Palapress) were investigated.

Flexural strength and flexural modulus of fiber-reinforced, soft-liner retained implant overdenture.

Purpose: To compare the flexural strength and modulus of ball-soft liner–retained overdentures vs ballsocket– retained overdentures, as well as to evaluate the effect of using glass fiber reinforcement on the mechanical properties of ball-soft liner–retained overdentures.

Materials And Methods: A total of 80 overdenture specimens were fabricated and divided equally into four groups (n = 20/group): specimens with a metal matrix (group 1); a silicone soft liner matrix (group 2); reinforced with one bundle of unidirectional Stick glass fiber placed above the silicone soft liner matrix (group 3); and reinforced with four weaves of bidirectional Stick Net glass fibers placed above the silicone soft liner matrix (group 4). Half of the specimens from each group were stored in water at room temperature (23°C ± 1°C) for 24 hours, while the other half were stored in water at 37°C for 30 days before being subjected to a static three-point loading test.

Effect of interface surface design on the fracture behavior of bilayered composites.

This study aimed to evaluate the effect of different interface designs on the load-bearing capacity of bilayered composite structures (BLS). Cylindrical specimens of BLS were prepared from base composite of 3.5 mm thickness and surface composite of 1.

Light Transmission of Novel CAD/CAM Materials and Their Influence on the Degree of Conversion of a Dual-curing Resin Cement.

Purpose: To evaluate the light transmission characteristics of different types, shades, and thicknesses of novel CAD/CAM materials and their effect on the degree of conversion (DC) of a dual-curing resin cement.

Materials And Methods: Square specimens (12 × 12 mm2) of three CAD/CAM materials - GC Cerasmart, Lava Ultimate, Vita Enamic - of different thicknesses (1.00, 1.

Preparation and characterization of high radio-opaque E-glass fiber-reinforced composite with iodine containing methacrylate monomer.

Objective: The purpose of this study was to prepare radio-opaque E-glass fiber-reinforced composite (EFRC) with synthesized iodine containing methacrylate monomer.

Methods: The synthesized iodine containing methacrylate monomer 2-hydroxy-3- methacryloyloxypropyl(2,3,5- triiodobenzoate) (HMTIB) was mixed with Bis-GMA and MMA in different mass ratio to prepare resin impregnating solution (RIS), and RIS without HMTIB was used as control. CQ and DMAEMA were added as photoinitiation system.

Reinforcing Effect of Glass Fiber-incorporated ProRoot MTA and Biodentine as Intraorifice Barriers.

Introduction: The purpose of this study was to investigate the fracture resistance of roots by using intraorifice barriers with glass fiber-incorporated ProRoot MTA and Biodentine.

Methods: The diametral tensile strength and compressive strength of ProRoot MTA and Biodentine were determined after incorporation of 5 wt% and 10 wt% alkali resistant (AR) glass fiber powder into both cements. On the basis of higher diametral tensile strength and compressive strength values, ProRoot MTA and Biodentine with 5 wt% AR glass fiber were selected for further testing as intraorifice barriers.

Micro-shear bond strength of different resin cements to ceramic/glass-polymer CAD-CAM block materials.

Purpose: The aim of this study was to evaluate the effects of hydrofluoric acid treatment on bond strength of resin cements to three different types of ceramic/glass containing CAD-CAM block composite materials.

Methods: CAD-CAM block materials of polymer infiltrated (Vita Enamic), resin nanoceramic (Lava Ultimate) and nanoceramic (Cerasmart) with a thickness of 1.5mm were randomly divided into two groups according to the surface treatment performed.

Influence of increment thickness on dentin bond strength and light transmission of composite base materials.

Objectives: Bulk-fill resin composites (BFCs) are gaining popularity in restorative dentistry due to the reduced chair time and ease of application. This study aimed to evaluate the influence of increment thickness on dentin bond strength and light transmission of different BFCs and a new discontinuous fiber-reinforced composite.

Materials And Methods: One hundred eighty extracted sound human molars were prepared for a shear bond strength (SBS) test.

Mechanical and structural characterization of discontinuous fiber-reinforced dental resin composite.

Objectives: This study evaluated several fiber- and matrix related factors and investigated different mechanical properties of discontinuous i.e. short fiber-reinforced composite (SFRC) (everX Posterior, eXP).

Surface roughness and the flexural and bend strength of zirconia after different surface treatments.

Statement Of Problem: Different surface treatments are commonly used during the fabrication of zirconia fixed dental prostheses. However, such treatments can affect the properties of the zirconia framework material.

Purpose: The purpose of this in vitro study was to determine the effect of different surface treatments on the surface roughness and flexural and bend strength of zirconia.

Mechanical properties, fracture resistance, and fatigue limits of short fiber reinforced dental composite resin.

Statement Of Problem: Cycling masticatory loads decrease the strength of particulate filler composites (PFCs) and initiate the failure process by fatigue. The life expectancy of a composite resin restoration under stress remains difficult to predict.

Purpose: The purpose of this study was to determine the fracture resistance and the compressive fatigue limits (CFL) of anterior crown restorations made of a short-fiber reinforced composite resin (SFC), to investigate selected mechanical properties of the material following standard test methods, and to observe their correlation with the CFL.

The effect of staining and vacuum sintering on optical and mechanical properties of partially and fully stabilized monolithic zirconia.

The effect of staining and vacuum sintering on optical properties and the bi-axial flexural strength of partially and fully stabilized monolithic zirconia (PSZ, FSZ) were evaluated. Disc-shaped specimens divided into three subgroups (n=15): non-stained, stained and non-stained with vacuum sintering. After staining and sintering, optical properties were evaluated using a reflection spectrophotometer and bi-axial flexural strength was tested using the piston-on-three balls technique.

Load-Bearing Capacity of Fiber-Reinforced Composite Abutments and One-Piece Implants.

Fiber-reinforced composites (FRC) can potentially help in a physiologic stress transmission due to its excellent biomechanical matching with living tissues. Novel one-piece FRC implants and abutments with two different fiber orientations were loaded until failure to assess the load-bearing capacity, fracture patterns, and precision of fit. The one-piece FRC implants showed significantly higher load-bearing capacity compared to FRC abutments regardless of the fiber orientation (p < 0.

Optical properties and light irradiance of monolithic zirconia at variable thicknesses.

Objectives: The aims of this study were to: (1) estimate the effect of polishing on the surface gloss of monolithic zirconia, (2) measure and compare the translucency of monolithic zirconia at variable thicknesses, and (3) determine the effect of zirconia thickness on irradiance and total irradiant energy.

Methods: Four monolithic partially stabilized zirconia (PSZ) brands; Prettau® (PRT, Zirkonzahn), Bruxzir® (BRX, Glidewell), Zenostar® (ZEN, Wieland), Katana® (KAT, Noritake), and one fully stabilized zirconia (FSZ); Prettau Anterior® (PRTA, Zirkonzahn) were used to fabricate specimens (n=5/subgroup) with different thicknesses (0.5, 0.

The effect of cycling deflection on the injection-molded thermoplastic denture base resins.

Objective: The aim of this study was to evaluate the effect of cycling deflection on the flexural behavior of injection-molded thermoplastic resins.

Materials And Methods: Six injection-molded thermoplastic resins (two polyamides, two polyesters, one polycarbonate, one polymethyl methacrylate) and, as a control, a conventional heat-polymerized denture based polymer of polymethyl methacrylate (PMMA) were used in this study. The cyclic constant magnitude (1.

Degree of conversion of dual-polymerizing cements light polymerized through monolithic zirconia of different thicknesses and types.

Statement Of Problem: Monolithic zirconia restorations are increasingly common. Dual-polymerizing cements have been advocated for cementation. The opacious nature of zirconia restoration can attenuate light, compromising optimal resin polymerization and eventually restoration debonding.

Three-dimensional finite element analysis of anterior two-unit cantilever resin-bonded fixed dental prostheses.

The aim of this study was to evaluate the influence of different framework materials on biomechanical behaviour of anterior two-unit cantilever resin-bonded fixed dental prostheses (RBFDPs). A three-dimensional finite element model of a two-unit cantilever RBFDP replacing a maxillary lateral incisor was created. Five framework materials were evaluated: direct fibre-reinforced composite (FRC-Z250), indirect fibre-reinforced composite (FRC-ES), gold alloy (M), glass ceramic (GC), and zirconia (ZI).

Preparation of antibacterial and radio-opaque dental resin with new polymerizable quaternary ammonium monomer.

Objective: A new polymerizable quaternary ammonium monomer (IPhene) with iodine anion was synthesized and incorporated into Bis-GMA/TEGDMA (50/50, wt/wt) to prepare antibacterial and radio-opaque dental resin.

Methods: IPhene was synthesized through a 2-steps reaction route, and its structure was confirmed by FT-IR and (1)H-NMR spectra. IPhene was incorporated into Bis-GMA/TEGDMA (50/50, wt/wt) with a series of mass fraction (from 10 wt.

Oxygen inhibition layer of composite resins: effects of layer thickness and surface layer treatment on the interlayer bond strength.

An oxygen inhibition layer develops on surfaces exposed to air during polymerization of particulate filling composite. This study assessed the thickness of the oxygen inhibition layer of short-fiber-reinforced composite in comparison with conventional particulate filling composites. The effect of an oxygen inhibition layer on the shear bond strength of incrementally placed particulate filling composite layers was also evaluated.

Effect of heat treatment of polymethyl methacrylate powder on mechanical properties of denture base resin.

Objectives: The aim of this research was to investigate the effects of heat treatment of polymethyl methacrylate powder on mechanical properties of denture base resin.

Methods: PMMA powder was applied after heat treatment at 100°C for 2h (code: HT100) or 130°C for 2h (code: HT130). The test specimens were fabricated from autopolymerizing resin to investigate the flexural properties of denture base resin cross-linked with methacrylated dendrimer, the surface microhardness of PMMA beads, and the thickness of the swollen layer of PMMA beads.

Synthesis of antibacterial and radio-opaque dimethacrylate monomers and their potential application in dental resin.

Objective: In this study, three dimethacrylate quaternary ammonium compounds N,N-bis[2-(3-(methacryloyloxy)propanamido)ethyl]-N-methyldodecyl ammonium iodide (QADMAI-12), N,N-bis[2-(3-(methacryloyloxy)propanamido)ethyl]-N-methylhexadecyl-ammonium iodide (QADMAI-16), and N,N-bis[2-(3-(methacryloyloxy)propanamido)ethyl]-N-methyloctadectyl ammonium iodide (QADMAI-18) were synthesized and proposed to be used as antibacterial and radio-opaque agents in dental resin.

Methods: All QADMAIs were synthesized through a 2-steps reaction route, and their structures were confirmed by FT-IR and 1H NMR spectra. Antibacterial activities against Streptococcus mutans (S.

Factors affecting the mechanical behavior of Y-TZP.

Aim: The aim was to evaluate the influence of sandblasting with various propulsion pressures on the phase transformation, flexural strength and Weibull modulus of a yttria stabilized tetragonal zirconia polycrystalline ceramic (Y-TPZ). In addition, the susceptibility of cyclic loading and low-temperature degradation under two different conditions (chemical and thermal aging) was investigated.

Materials And Methods: The specimens [105bar-shaped specimens (19.