scholarly journals Reflectance and transmittance of flowable dental resin composite predicted by the two-flux model: on the importance of analyzing the effective measurement geometry

2020 ◽  
Vol 2020 (28) ◽  
pp. 313-320
Author(s):  
Vincent Duveiller ◽  
Lou Gevaux ◽  
Raphaël Clerc ◽  
Jean-Pierre Salomon ◽  
Mathieu Hebert
Keyword(s):  
Spectral Reflectance ◽  
Prediction Accuracy ◽  
Resin Composite ◽  
Careful Analysis ◽  
Light Signal ◽  
Dental Resin ◽  
Flux Model ◽  
Measurement Geometry ◽  
Materials Used ◽  
Scatter Light

Flowable direct resin composite materials used in the dental domain are among materials that scatter light rather weakly, giving to millimeter-thick samples a certain translucent aspect. In order to predict the spectral reflectance and the color of such samples, the two-flux theory, i.e., Kubelka-Munk model (with Saunderson correction), remains the standard approach used in the dental domain, in spite of its known limitations when scattering is too weak. The present study, however, shows that a careful analysis of the light signal effectively measured on weakly scattering samples with instruments based, as usually recommended, on the d:8° measurement geometry, and a subsequent reevaluation of the parameters used in the Saunderson correction formulas with respect to the effective measurement geometry, can considerably improve the prediction accuracy of the model in both reflectance and transmittance modes, as confirmed by experiments carried out with samples of dental flowable resin composite material of different thicknesses. This broadens the applicability domain of the model, and might satisfy users preferring the simplicity of the two-flux model and the affordable equipment it needs to more relevant but more complex light scattering theories.

Characterization of Nano- and Micro-Filled Resin Composites Used as Dental Restorative Materials

2008 ◽  
Author(s):  
Dalia Abdel Hamid ◽  
Amal Esawi ◽  
Inas Sami ◽  
Randa Elsalawy
Keyword(s):  
Resin Composite ◽  
Physical And Mechanical Properties ◽  
Sem Analysis ◽  
Indentation Modulus ◽  
Resin Composites ◽  
Adhesively Bonded ◽  
Dental Resin ◽  
Tooth Structure ◽  
Dental Restorative

Adhesively-bonded resin composites have the advantage of conserving sound tooth structure with the potential for tooth reinforcement, while at the same time providing an aesthetically acceptable restoration. However, no composite material has been able to meet both the functional needs of posterior restorations and the superior aesthetics required for anterior restoration. In an attempt to develop a dental resin composite that had the mechanical strength of hybrid composite materials and the superior polish and gloss retention associated with microfilled materials, nanofilled resin composites have been introduced in the market. Although nanofillers are the most popular fillers utilized in current visible light-activated dental resin composites and are claimed to be the solution for the most challenging material limitations as a universal restorative material, the mechanisms by which these fillers influence the resin composite properties are not well explained. In this study, some physical and mechanical properties of a nanofilled resin composite containing 60 vol. % zirconia and silica fillers were evaluated and compared to those of a microhybrid resin composite of the same composition. The nanofilled resin composite was found to have equivalent polymerization shrinkage and depth of cure to the microhybrid material but a slightly lower degree of conversion and density. Regarding mechanical behaviour, although the nanocomposite was found to exhibit significantly higher wear resistance, and equivalent flexural strength, its indentation modulus and nanohardness were slightly lower. Field-emission scanning electron microscopy (FE-SEM) analysis was conducted in order to evaluate the microstructure and to obtain a better understanding of the effect of the nanofillers on the behaviour of the nanocomposite.

Accuracy of Kubelka–Munk reflectance theory for dental resin composite material

2012 ◽  
Vol 28 (7) ◽  
pp. 729-735 ◽  
Author(s):  
Sarah S. Mikhail ◽  
Shereen S. Azer ◽  
William M. Johnston
Keyword(s):  
Composite Material ◽  
Resin Composite ◽  
Dental Resin

Developing a novel antibacterial dental resin composite with improved properties

2019 ◽  
Vol 53 (22) ◽  
pp. 3085-3092 ◽  
Author(s):  
Xin Wen ◽  
Rashed Almousa ◽  
Gregory G Anderson ◽  
Dong Xie
Keyword(s):  
Compressive Strength ◽  
Antibacterial Activity ◽  
Resin Composite ◽  
Resin Composites ◽  
Dental Resin ◽  
Bacterial Viability ◽  
Mechanical And Physical Properties ◽  
Mechanical Strengths ◽  
Dental Restorative ◽  
Modified Resin

A novel antibacterial resin composite has been developed and evaluated. Glycerol dimethacrylate was derivatized to have an antibacterial moiety attached and incorporated to a conventional resin composite formulation. Compressive strength and bacterial viability were used to evaluate the modified resin composites. Results showed that the modified resin composites showed a significantly enhanced antibacterial activity along with improved mechanical and physical properties. It was found that bromine-containing resin composite showed a higher antibacterial activity than its chlorine-containing counterpart. The modified resin composites showed an increase of 37–41% in yield strength, 23–27% in modulus, 9–15% in diametral tensile strength and 5–12% in flexural strength and a decrease of 35–69% in bacterial viability, 20–37% in water sorption, 7–12% in shrinkage and 7–10% in compressive strength, as compared to unmodified resin composite. Within the limitations of this study, the modified resin composite may potentially be developed into a clinically useful dental restorative since it demonstrated good mechanical strengths and potent antibacterial function.

scholarly journals Thermogravimetric study of the behaviour of organic and inorganic polymers contained in four dental resin-based composites

2020 ◽  
pp. 096739112096753
Author(s):  
Thibault Canceill ◽  
Paul Pages ◽  
Sarah Garnier ◽  
Jany Dandurand ◽  
Sabine Joniot
Keyword(s):  
Thermal Stability ◽  
Resin Composite ◽  
Inorganic Polymers ◽  
Dental Resin ◽  
Humid Atmosphere ◽  
Water Imbibition ◽  
Before And After ◽  
Dimensional Variation ◽  
Loss Of Mass ◽  
Over Time

The composition of dental resin-based composite (RBC) matrix is partly responsible for many clinical failures in restorations, which may come from dimensional variation or instability in a wet environment. The objective of this study is therefore to evaluate the thermal stability over time of four dental RBC with different matrices. Silicone cylinders were filled with four different materials and then photopolymerized. To simulate ageing in the buccal environment, half of the samples were placed in a dark place at 37°C for 45 days in sealed compartments containing 2 ml of water. All the RBC produced were subjected to thermogravimetric analysis to measure the loss of mass as a function of temperature. Bis-GMA-based resins and Ormocer materials have similar curves before and after soaking in humid atmosphere. The curves of the UDMA resin are different before and after water ageing, meaning that water imbibition has modified the structure of the composite and its degradation. Even if many curves are similar within the same RBC at different polymerization times or at different pre- and post-ageing times, it is rare to observe a common kinetics between two different composites. Our results show good wet stability of polymerized dental RBC according to the manufacturer’s instructions, although the UDMA-based materials show more variation. It therefore seems that Ormocer resin composite with mass placement have ageing properties that can compete with those of conventional composites whereas those incremented on 2 mm layers are more sensitive to the time necessary for polymerization.

Inhibitive Effect of a New Dental Resin Composite on Enamel Artificial Caries

2014 ◽  
Vol 1058 ◽  
pp. 323-328
Author(s):  
Xin Yi Zhao ◽  
Shao Jie Hou ◽  
Shi Bao Li
Keyword(s):  
Resin Composite ◽  
Surface Hardness ◽  
Filling Material ◽  
Dental Resin ◽  
Buffer Solution ◽  
Partially Saturated ◽  
Enamel Demineralization ◽  
Restorative Materials ◽  
Before And After

Purpose To investigate the cariostatic effect of six restorative materials in vitro. Method Enamel blocks of bovine incisors were restored with six restorative materials (a conventional GIC, FujiIILC, Compoglass F, BeautifilII,Charisma and an experimental fluoride releasing resin composite) respectively with a gap of 270μm in width between each filling material and enamel. Then all restorations were immersed in a partially saturated acidic buffer solution at 37C for 3days. The surface enamel microhardness of the enamel blocks were measured before and after demineralization and the depth of enamel demineralization was measured using polarization microscope for each restoration.Results Enamel surface hardness of all restorations demonstrated significant reduced after demineralization ( p<0.05), and the order of hardness reduction is as follows: Charisma >BeautifilII≈Compoglass F≈Experimental Resin>FujiIILC>GIC ( p> 0.05). The order of the depth of enamel demineralization along the surface and the interface near the gap for the 5 materials is as follows: Charisma >BeautifilII≈Compoglass F ≈Experimental Resin>FujiIILC>GIC (P > 0.05). Conclusion The new fluoride releasing and recharging composite resin has the ability to prevent recurrent caries around the restoration and its ability is comparable to compomer materials.

Time-dependent nanoindentation behavior of high elastic modulus dental resin composites

2010 ◽  
Vol 25 (3) ◽  
pp. 529-536 ◽  
Author(s):  
Yijun Wang ◽  
Isabel K. Lloyd
Keyword(s):  
Elastic Modulus ◽  
Volume Fraction ◽  
Resin Composite ◽  
Acrylic Resin ◽  
Resin Matrix ◽  
Resin Composites ◽  
Dental Resin ◽  
Elastic Plastic ◽  
High Elastic Modulus ◽  
Continuous Stiffness Measurement

Nanoindentation and the viscous-elastic–plastic (VEP) model developed by Oyen and Cook for lightly filled thermoplastic polymer composites were used to characterize the elastic modulus, hardness, and viscoelastic response of a new high elastic modulus dental resin composite. The VEP model was used because loading rate studies indicated a viscous component in the loading/unloading response of our highly filled, thermosetting acrylic resin composites. Increasing the volume fraction of our high modulus filler increased the elastic modulus and hardness and decreased the viscous response in our composites. Coupling the filler and resin matrix with a commercial coupling agent like Metaltite or MPTMS (3-methacryloxypropyltrimethoxysilane) that ionically bonds to the filler and covalently bonds to the matrix decreases the viscous response and increases the hardness of the composite. The coupling agents did not affect the elastic modulus. The ability of the VEP model to predict load–displacement trajectories and the correlation of the elastic modulus and hardness values determined from the VEP model with those from the direct continuous stiffness measurement mode nanoindentation measurements indicate that the VEP model can be extended to highly filled, thermosetting systems. This is valuable since the potential to predict elastic, plastic, and viscous contributions to behavior should be valuable in the design and understanding of future highly filled resin composite systems.

Shear Bond Strength of a Resin Composite to Six Pulp Capping Materials Used in Primary Teeth

2020 ◽  
Vol 44 (4) ◽  
pp. 234-239
Author(s):  
Latifa Alhowaish ◽  
Fouad Salama ◽  
Mohammed Al-Harbi ◽  
Mohamad Abumoatti
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Primary Teeth ◽  
Resin Composite ◽  
Testing Machine ◽  
Bond Failure ◽  
Pulp Capping ◽  
Machine Failure ◽  
Materials Used

Aim: The purpose of this in vitro study was to assess the shear bond strength (SBS) and bond failure types of a resin-composite to six pulp-capping materials used in primary teeth. Study design: Eight-disc specimens from each pulp-capping material (6 groups) to bond to Filtek™ Z350 XT Flowable using a standard PVC tube (2×2mm). All groups were prepared according to the instruction of the manufacturer. The SBS was measured with a crosshead speed of 0.5 mm/min using a universal testing machine. Failure mode evaluation was completed using Digital Microscope by two independent examiners. Results: Urbical LC® showed the highest SBS (Mean±SD) followed by ProRoot® MTA and TheraCal LC® (35.422±2.910, 22.114±2.515, and 21.175±1.983) respectively. ANOVA showed significant differences between all groups (P=0.0001). Urbical LC® and Photac™ Fil QuickAplicap™ were statistically significant different from all other pulp-capping materials groups. ProRoot® MTA was statistically significant different than Biodentine® (P=0.0001) and Photac™ Fil (P=0.0001). The total number of bond failure was recorded for cohesive B failure/cohesive in the pulp-capping material (14) and adhesive failure (14). Conclusion: Most of the tested pulp-capping materials bonded to Filtek™ Z350 XT demonstrated clinically acceptable and high SBS. Urbical LC showed the highest SBS while Biodentine® showed the lowest SBS.

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