The Effect of Implant Length and Diameter on Stress Distribution around Single Implant Placement in 3D Posterior Mandibular FE Model Directly Constructed Form In Vivo CT.

A three-dimensional (3D) finite element (FE) model of the mandibular bone was created from 3D X-ray CT scan images of a live human subject. Simulating the clinical situation of implant therapy at the mandibular first molar, virtual extraction of the tooth was performed at the 3D FE mandibular model, and 12 different implant diameters and lengths were virtually inserted in order to carry out a mechanical analysis. (1) High stress concentration was found at the surfaces of the buccal and lingual peri-implant bone adjacent to the sides of the neck in all the implants.

Effect of accelerated aging on the fracture toughness of zirconias.

Statement Of Problem: Low temperature degradation (LTD) of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) is of concern.

Purpose: The purpose of this in vitro study was to assess the effect of accelerated aging on the Vickers hardness and fracture toughness of a newly developed Y-TZP and 2 primary Y-TZPs.

Material And Methods: Two primary 3 mol% Y-TZP, Lava (LA), Everest Zirconium Soft (EV), and a new 3 mol% Y-TZP, ZirTough (NZ) were assessed.

Structural stability of posterior retainer design for resin-bonded prostheses: a 3D finite element study.

The purpose of this in vitro study was to compare the stress distribution and natural frequency of different shape and thickness retainer designs for maxillary posterior resin-bonded prostheses using finite element (FE) method. A 3D FE model of a three unit posterior resin-bonded prosthesis analysis model was generated. Three different shaped retainer designs, viz.

Three-dimensional finite element analysis of Aramany Class IV obturator prosthesis with different clasp designs.

The purpose of this study was to evaluate the stress distribution on the alveolar bone surrounding abutment teeth and the displacement of the Aramany Class IV obturator prosthesis with two different clasp designs. Three-dimensional finite element models of an Aramany Class IV maxillary defect were constructed. Two different clasp designs on an obturator prosthesis (double Akers clasps and multiple Roach clasps) and two different load conditions (vertical and horizontal) were compared.

Effects of coloring agents applied during sintering on bending strength and hardness of zirconia ceramics.

The effects of coloring agents (Vita in-ceram 2000 YZ coloring liquid (VL) and IPS e.max ZirCAD (IS)) and shades (1, 3, and 5) applied during sintering on the bending strength and fracture toughness of zirconia ceramics was examined. No differences in the bending strength or fracture toughness were observed for the type of coloring agent used.

Effects of rotating fatigue on the mechanical properties of microhybrid and nanofiller-containing composites.

The objective of this study was to assess and compare the flexural strength and Vickers hardness of five nanofiller-containing composites (Filtek Supreme XT, Gradia Forte, Luna-Wing, GNH400N, GCUC) against five microhybrid composites (Meta Color Prime Art, Solidex, Estenia C&B, Ceramage, Clearfil Majesty) before and after rotating fatigue test (RFT). For each resin composite, 16 rectangular beam specimens (2 mm × 2 mm × 25 mm) were prepared and half of which were subjected to 1 × 10(4) cycles in RFT. Flexural strength was determined using a three-point bending test.

Effect of water temperature on cyclic fatigue properties of glass-fiber-reinforced hybrid composite resin and its fracture pattern after flexural testing.

Purpose: To evaluate in vitro the influence of dynamic loading applied to a glass-fiber-reinforced hybrid composite resin on its flexural strength in a moist, simulated oral environment.

Materials And Methods: Three-point flexural strength specimens were subjected to cyclic loading in water at 37°C and 55°C to investigate the influence of immersion temperature on impact fatigue properties. Specimens were subjected to cyclic impact loading at 1 Hz for up to 5 × 105 cycles to obtain the number of cycles to failure, the number of unbroken specimens after 5 × 105 cycles, and the residual flexural strength of unbroken specimens.

Effect of loading conditions on the fracture toughness of zirconia.

Purpose: A Vickers hardness indenter was pressed into yttria-stabilized zirconia (Y-TZP) by the indentation fracture method (IF method).

Methods: The effect on the calculated Vickers hardness, fracture toughness values, and indentation fracture load (9.8, 49, 98, 196, and 294 N) was examined to deduce the optimum conditions of the IF method.

Finite element analysis to compare stress distribution of gold alloy, lithium-disilicate reinforced glass ceramic and zirconia based fixed partial denture.

Aim: Clinical data indicate that veneer chipping of zirconia core is more likely than with ceramic-fused-to-metal structures. The purposes of this simulation study were to: (a) use two-dimensional finite element modeling to simulate stresses at the interface of three-unit posterior fixed partial dentures (FPDs) made with three different core materials; and (b) to investigate the influence of three different veneer thicknesses on the stress distribution within the veneer-core complex.

Methods: A mesio-distal cross-section of a three-unit FPD was digitized and used to create two-dimensional models of the teeth, supporting bone, different core materials (gold alloy, zirconia and lithia-disilicate reinforced glass ceramic), and different pontic preparation configurations (occlusal veneer thickness 1.

Effect of nanofiller on wear resistance and surface roughness of resin composites.

Objective: To compare the wear resistance and surface roughness of nanofiller-containing composites and microhybrid composites after simulated wear.

Methods: Five microhybrid composites and five nanofiller-containing resin composites were included in the study. Six cylindrical specimens with a diameter of 10 mm and a thickness of 6 mm for each material were prepared.

Accuracy of three-dimensional finite element modeling using two different dental cone beam computed tomography systems.

The aim of this study is to evaluate the accuracy of dental ceramic object three dimensional (3D) finite element model constructed directly from two different dental cone beam computed tomography (CT) systems. CT scanned one 10.0 × 10.

Measuring the effects of water immersion conditions on the durability of fiber-reinforced hybrid composite resin using static and dynamic tests.

The present study was designed to measure the durability of glass fiber-reinforced hybrid resins (FRC) in clinical applications. Accordingly, we studied the effects of static and dynamic loading as well as temperature changes inside the oral cavity, a moist environment, on the bending strength of FRC. The bending strength was measured using several tests, including an open-air bending strength test (AE), a 24-h water immersion test (WC1D), a 2-year water immersion test (WC2Y), a thermal cycling test (TC), a repeated in-water impact test at 37°C/10(5) (WI37), and a repeated in-water impact test at 55°C/10(5) (WI55).

Effects of mechanical properties of adhesive resin cements on stress distribution in fiber-reinforced composite adhesive fixed partial dentures.

Using finite element analysis (FEA), this study investigated the effects of the mechanical properties of adhesive resin cements on stress distributions in fiber-reinforced resin composite (FRC) adhesive fixed partial dentures (AFPDs). Two adhesive resin cements were compared: Super-Bond C&B and Panavia Fluoro Cement. The AFPD consisted of a pontic to replace a maxillary right lateral incisor and retainers on a maxillary central incisor and canine.

In vitro evaluation of the bonding durability of self-adhesive resin cement to titanium using highly accelerated life test.

The purpose of this in vitro study was to evaluate the bonding durability of three self-adhesive resin cements to titanium using the Highly Accelerated Life Test (HALT). The following self-adhesive resin cements were used to bond pairs of titanium blocks together according to manufacturers' instructions: RelyX Unicem, Breeze, and Clearfil SA Luting. After storage in water at 37°C for 24 h, bonded specimens (n=15) immersed in 37°C water were subjected to cyclic shear load testing regimes of 20, 30, or 40 kg using a fatigue testing machine.

Finite element analysis to compare stress distribution of connector of lithia disilicate-reinforced glass-ceramic and zirconia-based fixed partial denture.

This study used finite element method to analyze the stress distribution in connector of ceramic-based bilayer structures, in simulation of dental crown-like structures with a functional but weak veneer layer bonded onto a strong core layer. The purpose of this study was to evaluate the stress distribution at veneer/core interface of 2 different core materials [Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and lithia disilicate-reinforced glass-ceramic] using three-dimensional finite element analysis. Within the limitations of this study, finite element analysis showed that stress concentrations were located at the veneer/core interface of the connector in Y-TZP core models.

Three-dimensional finite element analysis of posterior fiber-reinforced composite fixed partial denture Part 2: influence of fiber reinforcement on mesial and distal connectors.

The aim of this study was to evaluate the influence of connectors under two different loading conditions on displacement and stress distribution generated in isotropic hybrid composite fixed partial denture (C-FPD) and partially anisotropic fiber-reinforced hybrid composite fixed partial denture (FRC-FPD). To this end, two three-dimensional finite element (FE) models of three-unit FPD from mandibular second premolar to mandibular second molar - intended to replace the mandibular first molar - were developed. The two loading conditions employed were a vertical load of 629 N (applied to eight points on the occlusal surface) and a lateral load of 250 N (applied to three points of the pontic).

The effect of surface treatment on bond strength of layering porcelain and hybrid composite bonded to zirconium dioxide ceramics.

Purpose: The purpose of this study was to investigate the differences between Rocatec (as surface treatment) and #600 polishing (as control) on shear bond strength of layering porcelain and hybrid composite to zirconium dioxide ceramics.

Methods: Manufactured zirconia blocks used in this study were yttrium partially stabilized zirconia (YTZ(®)), and veneering materials were NobelRondo Zirconia Dentin A2 High Value (NZR) and Estenia C&B (ES). Total 48 zirconia blocks were fabricated (10 mm × 10 mm × 20 mm).

Effect of cyclic impact load on shear bond strength of zirconium dioxide ceramics.

Purpose: To investigate the influence of cyclic impact load and the number of load cycles on compressive shear bond strength under the three different cements.

Materials And Methods: The following materials were used: Super Bond C&B (SB) and Panavia Fluoro Cement (PF) as adhesive resin cements, Fuji Luting (FL) as a resin-modified glass-ionomer cement, and zirconium dioxide ceramics as adherend. Before the shear bond test, three different impact loading conditions (compressive direction, shear direction, and no impact) and the number of load cycles (1 to 106 cycles), were performed.

High volume individual fibre post versus low volume fibre post: the fracture load of the restored tooth.

Objectives: The purpose of this study was to evaluate the fracture loads of post-and-core systems with two different individually formed fibre post designs and polymerization conditions.

Methods: Totally seventy-two (n=8/group) bovine teeth were cut and made up the root length of 15.0mm.

Development of 3D CAD/FEM Analysis System for Natural Teeth and Jaw Bone Constructed from X-Ray CT Images.

A three-dimensional finite element model of the lower first premolar, with the three layers of enamel, dentin, and pulp, and the mandible, with the two layers of cortical and cancellous bones, was directly constructed from noninvasively acquired CT images. This model was used to develop a system to analyze the stresses on the teeth and supporting bone structure during occlusion based on the finite element method and to examine the possibility of mechanical simulation.

Effect of self-adhesive resin cement and tribochemical treatment on bond strength to zirconia.

Aim: To evaluate the interactive effects of different self-adhesive resin cements and tribochemical treatment on bond strength to zirconia.

Methodology: The following self-adhesive resin cements for bonding two zirconia blocks were evaluated: Maxcem (MA), Smartcem (SM), Rely X Unicem Aplicap (UN), Breeze (BR), Biscem (BI), Set (SE), and Clearfil SA luting (CL). The specimens were grouped according to conditioning as follows: Group 1, polishing with 600 grit polishing paper; Group 2, silica coating with 110 microm Al2O3 particles which modified with silica; and, Group 3, tribochemical treatment--silica coating + silanization.

Bonding of self-adhesive resin cements to enamel using different surface treatments: bond strength and etching pattern evaluations.

This study evaluated the shear bond strengths and etching patterns of seven self-adhesive resin cements to human enamel specimens which were subjected to one of the following surface treatments: (1) Polishing with #600 polishing paper; (2) Phosphoric acid; (3) G-Bond one-step adhesive; or (4) Phosphoric acid and G-Bond. After surface treatment, the human incisor specimens were bonded to a resin composite using a self-adhesive resin cement [Maxcem (MA), RelyX Unicem (UN), Breeze (BR), BisCem (BI), seT (SE), Clearfil SA Luting (CL)] or a conventional resin cement [ResiCem (RE)]. Representative morphology formed with self-adhesive resin cements showed areas of etched enamel intermingled with areas of featureless enamel.

Stress and strain analysis of the bone-implant interface: a comparison of fiber-reinforced composite and titanium implants utilizing 3-dimensional finite element study.

This study analyzed stress and strain mediated by 2 different implant materials, titanium (Ti) and experimental fiber-reinforced composite (FRC), on the implant and on the bone tissue surrounding the implant. Three-dimensional finite element models constructed from a mandibular bone and an implant were subjected to a load of 50 N in vertical and horizontal directions. Postprocessing files allowed the calculation of stress and strain within the implant materials and stresses at the bone-to-implant interface (stress path).

Studies on mechanical strength, thermal expansion of layering porcelains to alumina and zirconia ceramic core materials.

The aim of this study was to evaluate and clarify the various mechanical properties and behavior of layering porcelains (Tokuyama Dental Ceramic, IPS Empress 2, Cerabien, Vitadura, Creation) used for veneering high-strength ceramic core materials. The layering porcelains studied exhibited the following range of mechanical properties: compressive strength at 586-1091 MPa, bending strength at 30-97 MPa, diametral tensile strength at 16-28 MPa, Vickers hardness at 481-647 Hv, and fracture toughness at 1.36-2.

Three-dimensional finite element analysis of posterior fiber reinforced composite fixed partial denture: framework design for pontic.

This study investigated the effects of two types of loading conditions on mechanical behavior of the pontic of composite fixed partial denture (C-FPD) and fiber reinforced composite fixed partial denture (FRC-FPD). Two types of FE model of posterior bridge were developed. Two types of loading conditions, i.