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Search Results: 1 - 10 of 3569 matches for " resin composites "
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The Effect of the Light Intensity and Light Distances of LED and QTH Curing Devices on the Hardness of Two Light-Cured Nano-Resin Composites  [PDF]
Pnina Segal, Diva Lugassy, Eitan Mijiritsky, Michal Dekel, Ariel Ben-Amar, Zeev Ormianer, Shlomo Matalon
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.611106
Abstract: Background: Effective polymerization of the composite resin is essential to obtain long term clinical success and has a great importance obtaining improved mechanical properties. The purpose of this study was to measure the effect of the light intensity of LED and QTH curing devices in relation to the light distances, on the hardness (KHN) of two light cure nano-resin composite. Material and Methods: The top and bottom surfaces of the two nanofill composite specimens were evaluated. Two LED and two QTH light curing devices were used at nine different distances. Light intensity was measured with two radiometers placed at these same distances from the curing tip. 360 pvc dies were prepared with circular cavity 3 mm in diameter and 2 mm thick. The tested materials were placed in each cavity. The different light curing distances were standardized by adding pvc spacers dies at different height matching the different distances. Top and bottom surface microhardness were evaluated with a Micro Hardness Tester in knoop hardness numbers (Kg/mm2). Data were statistically analyzed using: Three-way ANOVA, Tukey and Pearsons test. Results: It was revealed that there was a statistically significant difference in microhardness between the composites (p < 0.001), between the nine distances (p < 0.001) and between the four light curing devices (p < 0.001). Increasing the distance of the light source from composite resin, the light intensity and the microhardness values at the top and bottom surface decrease. LED light curing devices produced a greater microhardness results at the bottom surface of the specimens. The Filtek Ultimate nanocomposite (3 m) showed highest microhardness values on the top and bottom surfaces, polymerized with all four curing devices and all nine distances compared to Empress Direct nano composite (Ivoclar vivadent). Clinical significant: Even with high power LED curing light, the distance between the tip of the light source and the restoration surface should be as close as possible. In this study, Filtek Ultimate showed better results (highest microhardness values) than Empress Direct.
Comparison of One-Step and Multistep Polishing Systems for the Surface Roughness of Resin Composites  [PDF]
Ismail Hakk? Baltac?o?lu, Ozgur Irmak, Nuran Ulusoy, Esra Cengiz, Y?ld?r?m Hakan Ba???
Open Journal of Stomatology (OJST) , 2016, DOI: 10.4236/ojst.2016.63009
Abstract: Aim: This study analyzed the effect of different finishing and polishing systems on the surface roughness of a microfilled (Amaris), and a nanofilled resin composite (Clearfil Majesty Esthetic) using Scanning electron microscope (SEM) analysis and surface roughness tester. Materials and Methods: Thirty five specimens of each material were prepared in a plexiglass mold (10 mm in diameter and 2 mm in depth) and cured against a Mylar matrix strip to create a baseline surface. The average surface roughness was measured using a surface profilometer (Mahr Perthometer SP4, Germany) in three different positions on each sample before and after finishing with one of the seven finishing procedures: Procedure 1: Mylar strip (control), Procedure 2: Tungsten carbide burs, Procedure 3: Diamond burs, Procedure 4: Procedure 2 + one-step diamond micropolisher (PoGo), Procedure 5: Procedure 2 + multi-step discs (Super-snap), Procedure 6: Procedure 3 + one-step diamond micropolisher (PoGo), Procedure 7: Procedure 3 + multi-step discs (Super-snap). The obtained data were analyzed using two-way analysis of variance (ANOVA) and Duncan test at a p = 0.05 significance level. Results: Nanofilled composite showed significantly lower Ra values than microfilled composite in procedures 4, 6 and 7 (p < 0.05). In other procedures, there were no significant differences among composites (p > 0.05). Conclusion: Nanofilled resin composite showed significantly lower Ra values than microfilled resin composite. Regardless of finishing methods, diamond micro-polisher produced smoother surfaces than polishing discs.
Nanoindentation Study on Mechanical Properties of Nano-SiO2/Dental Resin Composites  [PDF]
Chao Zha, Jianhua Hu, Ainong Li, Shangyu Huang, Hanxing Liu, Gang Chen, Anqi Lei, Zuoqi Zhang, Bei Li, Zhengzhi Wang
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.64008
Abstract:
The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the filling content of nano-SiO2 particles on the mechanical properties of the dental composites was studied as well. The experimental results showed that the incorporation of the nano-SiO2 particles at low concentrations (up to 10 wt.%) can apparently increase the hardness and elastic modulus of the dental rein composites. The plasticity index indicates a best elastic recovery capability at a proper amount (4 wt.%) of the nanoparticles. Combined with the infrared spectrum, the mechanical enhancement mechanisms of the dental resin composites were analyzed.
Uso de resíduo industrial a base de resina fenólica como carga para o polipropileno
Cavalcante, André P.;Canto, Leonardo B.;
Polímeros , 2012, DOI: 10.1590/S0104-14282012005000031
Abstract: the aim of this study was to assess the technical feasibility of using industrial waste composed of phenolic resin, lignocellulose, calcium carbonate, talc, mica and carbon black as filler for polypropylene (pp). composites of pp with 10, 15 and 20 wt% of the waste were processed in a twin-screw extruder followed by injection molding. molded composites were characterized by scanning electron microscopy (sem), thermal analyses (dsc and tga), mechanical tests (tensile, flexural and impact) and thermo-mechanical test (hdt). the composites showed residue particles with sizes less than 500 μm dispersed in the pp matrix. the residue particles acted as nucleating agents for pp crystallization. the composites showed greater thermal degradation resistance as compared to pp. the composites showed a balance of stiffness and mechanical strength with increase of the flexural module and decrease of the tensile strength. the notched impact strength was not altered and the heat distortion temperature (hdt) of the composites was increased as compared to pp. the performance of the composites developed here showed that the industrial waste based on phenolic resin can be used as functional filler for pp. furthermore, these composites are an alternative for the recycling of the phenolic resin industrial waste.
EFFECT OF HARDENER ON MECHANICAL PROPERTIES OF CARBON FIBRE REINFORCED PHENOLIC RESIN COMPOSITES
S. SULAIMAN,R. YUNUS,N. A. IBRAHIM,F. REZAEI
Journal of Engineering Science and Technology , 2008,
Abstract: In this paper the effect of hardener on mechanical properties of carbon reinforced phenolic resin composites is investigated. Carbon fibre is one of the most useful reinforcement materials in composites, its major use being the manufacture of components in the aerospace, automotive, and leisure industries. In this study, carbon fibres are hot pressed with phenolic resin with various percentages of carbon fibre and hardener contents that range from 5-15%. Composites with 15% hardener content show an increase in flexural strength, tensile strength and hardness. The ultimate tensile strength (UTS), flexural strength and hardness for 15% hardener are 411.9 MPa, 51.7 MPa and 85.4 HRR respectively.
In vitro comparative analysis of resistance to compression of laboratory resin composites and a ceramic system
Montenegro Alexandre,do Couto Cintia,Ventura Paulo,Gouvea Cresus
Indian Journal of Dental Research , 2010,
Abstract: Background: Restorative materials must be capable not only of restoring the patient′s masticatory function, but also to rescue the self-esteem of those maculated by a disharmonious smile. Among the esthetic materials available on the market, the choice frequently lies between ceramic or indirect laboratory resin restorations. Aim: This study assessed the resistance to compression of two laboratory resins found on the market, namely Artglass and Targis , considering Omega 900 ceramic from Vita as control. Materials and Methods: With the aid of stainless steel matrices, with internal dimensions of 8.0 mm diameter at the base, 9.0 mm in the top portion and 4.0 mm height, 15 test specimens were made, being 5 of each material to be tested. The test specimens were kept in distilled water for 72 hours and submitted to an axial load by the action of a point with a rounded tip 2 mm in diameter, adapted to an EMIC 500 universal test machine. The compression speed was 0.5 mm/min, with a load cell capacity of 200 Kgf. Results: The means of the results were calculated in kilogram-force (Kgf). The results found were treated by analysis of variance (ANOVA) and the differences found among the groups were identified by the Tukey test (5%). Conclusion: It was observed that the material Omega 900 offered significantly greater resistance to compression than the other two materials, which did not present statistically significant difference between them.
Studies on interacting Blends of Acrylated Epoxy resin based Poly(Ester-Amide)s and Vinyl EsterResin  [PDF]
Pragnesh N. Dave, Nikul N. Patel
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.27106
Abstract: Epoxy resin based Unsaturated poly(ester-amide) resins (UPEAs) can be prepared by many methods but here these were prepared by reported method [1]. These UPEAs were then treated with acrylotl chloride to afford acrylated UPEAs resin (i.e. AUPEAs). Interacting blends of equal proportional AUPEAs and vinyl ester epoxy (VE) resin were prepared. APEAs and AUPEAs were characterized by elemental analysis, molecular weight determined by vapour pressure osmometer and by IR spectral study and by thermogravimetry. The curing of interacting blends was monitored on differential scanning calorimeter (DSC). Based on DSC data in situ glass reinforced composites of the resultant blends have been prepared and characterized for mechanical, electrical and chemical properties. Unreinforced blends were characterized by thermogravimetry (TGA).
Synthesis and evaluation of a novel antibacterial dental resin composite with quaternary ammonium salts  [PDF]
Yiming Weng, Xia Guo, Voon Joe Chong, Leah Howard, Richard L. Gregory, Dong Xie
Journal of Biomedical Science and Engineering (JBiSE) , 2011, DOI: 10.4236/jbise.2011.43021
Abstract: The novel quaternary ammonium bromide (QAB)-containing oligomers were synthesized and applied for developing an antibacterial resin composite. Compressive strength (CS) and S. mutans (an oral bacteria strain) viability were used to evaluate the mechanical strength and antibacterial activity of the formed composites. All the QAB-modified resin composites showed significant antibacterial activity and mechanical strength reduction. Increasing chain length and loading significantly enhanced the antibacterial activity but dramatically reduced the CS as well. The 30-day aging study showed that the incorporation of the QAB accelerated the degradation of the composite, suggesting that the QAB may not be well suitable for development of antibacterial dental resin composites or at least the QAB loading should be well controlled, unlike its use in dental glass-ionomer cements. The work in this study is beneficial and valuable to those who are interested in studying antibacterial dental resin composites.
Effect of Filler Size and Temperature on Packing Stress and Viscosity of Resin-composites
Haitham Elbishari,Julian Satterthwaite,Nick Silikas
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12085330
Abstract: The objective of this study was to investigate the effect of filler size on the packing stress and viscosity of uncured resin-composite at 23 °C and 37 °C. A precision instrument used was designed upon the penetrometer principle. Eight resin-composite materials were tested. Packing-stress ranged from 2.60 to 0.43 MPa and viscosity ranged from 2.88 to 0.02 MPa.s at 23 °C. Values for both properties were reduced significantly at 37 °C. Statistical analysis, by ANOVA and post hoc methods, were carried out to check any significant differences between materials tested (P < 0.05). Conclusions: Filler size and distribution will affect the viscosity and packing of resin-composites during cavity?placement.
99mTc in the evaluation of microleakage of composite resin restorations with SonicFillTM. An in vitro experimental model  [PDF]
Carrilho Eunice, Abrantes Margarida, Casalta-Lopes Jo?o, Botelho Filomena, Paula Anabela, Ambrósio Pedro, Marto Carlos Miguel, Rebelo Diana, Marques Joana, Polido Mário, Ferreira Manuel Marques
Open Journal of Stomatology (OJST) , 2012, DOI: 10.4236/ojst.2012.24058
Abstract: Introduction: The composite SonicFillTM (Kerr/Kavo) is indicated for posterior restorations, with a single increment up to 5 mm due to reduced polymerization shrinkage, thus reducing working time. Aim: Evaluation of marginal microleakage with SonicFillTM. Method and Materials: There were sectioned sixty noncarious human molars in the occluso-cervical direction. Class V cavities were prepared on each tooth with gingival margin walls in a standardized way. The specimens were divided into 4 groups: group 1—restored with SonicFillTM (Kerr/Kavo), group 2—restored with FiltekTM SupremeXTE (3M ESPE), group 3—the cavities were not restored; group 4—restored with SonicFillTM (Kerr/Kavo). In groups 1, 2 and 4 the enamel was conditioned with 37% orthophosphoric acid and applied the self-etch adhesive system Clear- fillTM SE BOND (Kuraray). The specimens were stored in distilled water at 37?C for 7 days. After, the specimens, were immersed in a solution of 99mTc-Pertechnetate and the radioactivity was assessed with a gamma camera. The nonparametric Kruskal-Wallis and Mann-Whitney test with Bonferroni correction at a significance level of 5% were used for the statistical analyses. Results: There are significant differences between the positive and negative control groups and between these and experimental groups (p < 0.05). There are no statistically significant differences between the specimens restored with SonicFillTM and FiltekTM SupremeXTE. Conclusion: The new composite SonicFillTM and FiltekTM SupremeXTE showed no difference concerning dye penetration. The Sonic- FillTM restorative system showed no influence in concerning microleakage.
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