Resin-Bonded Fiber-Reinforced Composite for Direct Replacement of Missing Anterior Teeth: A Clinical Report

Missing anterior teeth is of serious concern in the social life of a patient in most of societies. While conventional fixed partial dentures and implant-supported restorations may often be the treatment of choice, fiber-reinforced composite (FRC) resins offer a conservative, fast, and cost-effective alternative for single and multiple teeth replacement. This paper presents two cases where FRC technology was successfully used to restore anterior edentulous areas in terms of esthetic values and functionality

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 amaxillary lateral incisorwas created. Five frameworkmaterialswere evaluated: direct fibre-reinforced composite (FRC-Z250), indirect fibre-reinforced composite (FRC-ES), gold alloy (M), glass ceramic (GC), and zirconia (ZI). Finite element analysis was performed and stress distribution was evaluated. A similar stress pattern, with stress concentrations in the connector area, was observed in RBFDPs for all materials.Maximal principal stress showed a decreasing order: ZI >M>GC> FRC-ES > FRCZ250. The maximum displacement of RBFDPs was higher for FRC-Z250 and FRC-ES than for M, GC, and ZI. FE analysis depicted differences in location of the maximum stress at the luting cement interface between materials. For FRC-Z250 and FRC-ES, the maximum stress was located in the upper part of the proximal area of the retainer, whereas, for M, GC, and ZI, the maximum stress was located at the cervical outline of the retainer. The present study revealed differences in biomechanical behaviour between all RBFDPs.The general observation was that a RBFDP made of FRC provided a more favourable stress distribution

Summary of the CMS Discovery Potential for the MSSM SUSY Higgses

This work summarises the present understanding of the expected MSSM SUSY Higgs reach for CMS. Many of the studies presented here result from detailed detector simulations incorporating final CMS detector design and response. With 30 fb-1 the h -> gamma,gamma and h -> bb channels allow to cover most of the MSSM parameter space. For the massive A,H,H+ MSSM Higgs states the channels A,H -> tau,tau and H+ -> tau,nu turn out to be the most profitable ones in terms of mass reach and parameter space coverage. Consequently CMS has made a big effort to trigger efficiently on taus. Provided neutralinos and sleptons are not too heavy, there is an interesting complementarity in the reaches for A,H -> tau,tau and A,H -> chi,chi.Comment: 19 pages, 27 figure

Quark cluster signatures in deuteron electromagnetic interactions

A suggestion is made for distinguishing 2N and 6q short range correlations within the deuteron. The suggestion depends upon observing high momentum backward nucleons emerging from inelastic electromagnetic scattering from a deuteron target. A simple model is worked out to see the size of effects that may be expected.Comment: 18 pages (3 figures available as hard copy), WM-94-10

Flexural properties of fiber reinforced root canal posts.

AbstractOBJECTIVES: Fiber-reinforced composite (FRC) root canal posts have been introduced to be used instead of metal alloys and ceramics. The aim of this study was to investigate the flexural properties of different types of FRC posts and compare those values with a novel FRC material for dental applications.METHODS: Seventeen different FRC posts of various brands (Snowpost, Carbopost, Parapost, C-post, Glassix, Carbonite) and diameters, (1.0-2.1 mm) and a continuous unidirectional E-glass FRC polymerized by light activation to a cylindrical form (everStick, diameter 1.5 mm) as a control material were tested. The posts (n=5) were stored at room's humidity or thermocycled (12.000 x, 5 degrees C/55 degrees C) and stored in water for 2 weeks before testing. A three-point bending test (span=10 mm) was used to measure the flexural strength and modulus of FRC post specimens.RESULTS: Analysis of ANOVA revealed that thermocycling, brand of material and diameter of specimen had a significant effect (p<0.001) on the fracture load and flexural strength. The highest flexural strength was obtained with the control material (everStick, 1144.9+/-99.9 MPa). There was a linear relationship between fracture load and diameter of posts for both glass fiber and carbon fiber posts. Thermocycling decreased the flexural modulus of the tested specimens by approximately 10%. Strength and fracture load decreased approximately 18% as a result of thermocycling.SIGNIFICANCE: Considerable variation can be found in the calculated strength values of the studied post brands. Commercial prefabricated FRC posts showed lower flexural properties than an individually polymerised FRC material.</div

The effect of chlorhexidine and dimethyl sulfoxide on long-term sealing ability of two calcium silicate cements in root canal

Objectives. To evaluate the long-term effect of chlorhexidine (CHX) and dimethyl sulfoxide (DMSO) on the sealing ability and biomineralization of two different calcium silicate cements (CSC) in root canal. Methods. Sixty human third molar root canals were obturated with ProRoot MTA or Biodentine. Before obturation the canals were irrigated with saline (control), 2% CHX or 5% DMSO. Microleakage was tested after three days and after six months. After additional six months (12 months after root filling) the roots were cut into 2 mm thick dentine discs. The discs were stored in artificial saliva for one year. The bond strength was measured with the push-out method, and the failure mode was evaluated with a stereomicroscope. The most apical disc of each tooth was used for Vickers hardness test. Results. No significant differences between the groups was found in initial microleakage. The leakage increased significantly during the 6-month storage in all groups except in Biodentine-CHX group and Biodentine-DMSO group. CHX and DMSO irrigation significantly increased the leakage with ProRoot MTA with time, but there was no statistically significant difference compared to the ProRoot MTA-control group at six months' time point. CHX significantly reduced the push-out bond strength of ProRoot MTA. With Biodentine irrigation with CHX or DMSO resulted with significantly higher push-out strength compared to the Biodentine control group. Fracture analysis showed statistically significant difference in the distribution of the fractures between the groups, but neither CHX nor DMSO change the fracture pattern statistically significantly. With Vickers hardness test ProRoot MTA with and without DMSO as the final irrigant showed significantly higher dentin hardness than any Biodentine-group. Significance. Considering that aging increased the leakage in all groups except with Biodentine-DMSO and the differences in the push-out strength and surface microhardness data, it appears that the time-related biomineralizing effect of MTA and Biodentine does not improve sealing to dentin. CHX significantly reduced ProRoot MTA bond strength and increased pure adhesive failures with both cements. (C) 2020 Published by Elsevier Inc. on behalf of The Academy of Dental Materials.Peer reviewe

The effect of chlorhexidine and dimethyl sulfoxide on long-term sealing ability of two calcium silicate cements in root canal

Objectives. To evaluate the long-term effect of chlorhexidine (CHX) and dimethyl sulfoxide (DMSO) on the sealing ability and biomineralization of two different calcium silicate cements (CSC) in root canal. Methods. Sixty human third molar root canals were obturated with ProRoot MTA or Biodentine. Before obturation the canals were irrigated with saline (control), 2% CHX or 5% DMSO. Microleakage was tested after three days and after six months. After additional six months (12 months after root filling) the roots were cut into 2 mm thick dentine discs. The discs were stored in artificial saliva for one year. The bond strength was measured with the push-out method, and the failure mode was evaluated with a stereomicroscope. The most apical disc of each tooth was used for Vickers hardness test. Results. No significant differences between the groups was found in initial microleakage. The leakage increased significantly during the 6-month storage in all groups except in Biodentine-CHX group and Biodentine-DMSO group. CHX and DMSO irrigation significantly increased the leakage with ProRoot MTA with time, but there was no statistically significant difference compared to the ProRoot MTA-control group at six months' time point. CHX significantly reduced the push-out bond strength of ProRoot MTA. With Biodentine irrigation with CHX or DMSO resulted with significantly higher push-out strength compared to the Biodentine control group. Fracture analysis showed statistically significant difference in the distribution of the fractures between the groups, but neither CHX nor DMSO change the fracture pattern statistically significantly. With Vickers hardness test ProRoot MTA with and without DMSO as the final irrigant showed significantly higher dentin hardness than any Biodentine-group. Significance. Considering that aging increased the leakage in all groups except with Biodentine-DMSO and the differences in the push-out strength and surface microhardness data, it appears that the time-related biomineralizing effect of MTA and Biodentine does not improve sealing to dentin. CHX significantly reduced ProRoot MTA bond strength and increased pure adhesive failures with both cements. (C) 2020 Published by Elsevier Inc. on behalf of The Academy of Dental Materials.Peer reviewe

The Effect of Exposed Glass Fibers and Particles of Bioactive Glass on the Surface Wettability of Composite Implants

Measurement of the wettability of a material is a predictive index of cytocompatibility. This study was designed to evaluate the effect of exposed E-glass fibers and bioactive glass (BAG) particles on the surface wettability behavior of composite implants. Two different groups were investigated: (a) fiber reinforced composites (FRCs) with different fiber orientations and (b) polymer composites with different wt. % of BAG particles. Photopolymerized and heat postpolymerized composite substrates were made for both groups. The surface wettability, topography, and roughness were analyzed. Equilibrium contact angles were measured using the sessile drop method. Three liquids were used as a probe for surface free energy (SFE) calculations. SFE values were calculated from contact angles obtained on smooth surfaces. The surface with transverse distribution of fibers showed higher (P < 0.001) polar (γP) and total SFE (γTOT) components (16.9 and 51.04 mJ/m2, resp.) than the surface with in-plane distribution of fibers (13.77 and 48.27 mJ/m2, resp.). The increase in BAG particle wt. % increased the polar (γP) value, while the dispersive (γD) value decreased. Postpolymerization by heat treatment improved the SFE components on all the surfaces investigated (P < 0.001). Composites containing E-glass fibers and BAG particles are hydrophilic materials that show good wettability characteristics

Biomechanical behavior of cavity configuration on micropush-out test : a finite-element-study

Objective: The objective of this study was to simulate the micropush-out bond strength test from a biomechanical point of view. For this purpose, stress analysis using finite element (FE) method was performed. Study design: Three different occlusal cavity shapes were simulated in disc specimens (model A: 1.5 mm cervical, 2 mm occlusal diameter; model B: 1.5 mm cervical, 1.75 mm occlusal diameter; model C: 1.5 mm cervical, 1.5 mm occlusal diameter). Quarter sizes of 3D FE specimen models of 4.0×4.0×1.25 mm3 were constructed. In order to avoid quantitative differences in the stress value in the models, models were derived from a single mapping mesh pattern that generated 47.182 elements and 66.853 nodes. The materials that were used were resin composite (Filtek Z250, 3M ESPE), bonding agent (Adper Scotchbond Multi-Purpose, 3M ESPE) and dentin as an isotropic material. Loading conditions consisted of subjecting a press of 4 MPa to the top of the resin composite discs. The postprocessing files allowed the calculation of the maximum principal stress, minimum principal stress and displacement within the disc specimens and stresses at the bonding layer. FE model construction and analysis were performed on PC workstation (Precision Work Station 670, Dell Inc.) using FE analysis program (ANSYS 10 Sp, ANSYS Inc.). Results: Compressive stress concentrations were observed equally in the bottom interface edge of dentin. Tensile stresses were observed on the top area of dentin and at the half of lower side of composite under the loading point in all of the FE models. Conclusions: The FE model revealed differences in displacement and stress between different cavity shaped disc specimens. As the slope of the cavity was increased, the maximum displacement, compressive and tensile stresses also increased