scholarly journals Influence of the photoactivation mode and the distance of light-curing unit in mechanical properties of silorane and methacrylate based resins.

2013 ◽  
Vol 1 (4) ◽  
pp. 281
Author(s):  
Bárbara Malta Neves Oliveira ◽  
Renata Pereira ◽  
Maria Do Carmo Aguiar Jordão Mainardi ◽  
Gláucia Maria Bovi Ambrosano ◽  
Débora Alves Nunes Lima ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Composite Resin ◽  
Resin Composite ◽  
Composite Resins ◽  
Bottom Surface ◽  
Base Resin ◽  
Light Curing ◽  
Base Composite

This in vitro work had as aim evaluate the effect of photoactivation mode and the distance of light-curing unit (LCU) in microhardness Knoop (KHN) and the diametrical tensile strength (DTS) of methacrylate and silorane-based resins. Filtek Z250 (methacrylate-based resin) and Filtek P90 (silorane-based resin), both from 3M Espe, were selected for this work. The photoactivation were performed by one of the following modes: Valo (Ultradent) at 1000 mW/cm2 X 18 s (S); 1400 mW/cm2 X 12 s (HP); 3200 mW/cm2 X 6 s (PE); and XL 3000 (3M Espe) at 450 mW/cm2 X 40 s (XL). Resin composite were inserted in one increment into a bipartide Teflon matrix (5mm X 2mm) and photoactivated at 0mm, 3 or 6mm from the increment surface, according to the experimental groups. After the confection, the specimens (n=5) were submitted to KHN on the top (T) and on the bottom (B), and to DTS. Data were analyzed through ANOVA/Tukey tests (α=5%). It was observed that Filtek Z250 presented values of KHN equal or higher than Filtek P90. The surface T presented higher values of KHN than B. For both composite resins, the values of KHN on the surface B were lower, as higher the distance of LCU. In relation to DTS, the higher values were observed in Filtek Z250. Silorane base composite resin presented lower mechanical properties when compared to the methacrylate base resin. The distance of LCU is able to influence the microhardness of bottom surface. 

Effect of Light Curing Modes and Light Curing Time on the Microhardness of a Hybrid Composite Resin

2007 ◽  
Vol 8 (6) ◽  
pp. 1-8 ◽  
Author(s):  
José Roberto Lovadino ◽  
Gláucia Maria Bovi Ambrosano ◽  
Flávio Henrique Baggio Aguiar ◽  
Aline Braceiro ◽  
Débora Alves Nunes Leite Lima
Keyword(s):  
Hybrid Composite ◽  
High Intensity ◽  
Composite Resin ◽  
Resin Composite ◽  
Composite Resins ◽  
Bottom Surface ◽  
Curing Time ◽  
Experimental Conditions ◽  
Light Curing ◽  
Effect Of Light

Abstract Aims The aim of this in vitro study was to evaluate the influence of light curing modes and curing time on the microhardness of a hybrid composite resin. Methods and Materials Forty-five Z250 composite resin specimens (3M-ESPE Dental Products, St. Paul, MN, USA) were randomly divided into nine groups (n=5): three polymerization modes (conventional - 550 mW/ cm2; light-emitting diodes (LED) - 360mW/cm2, and high intensity - 1160 mW/cm2) and three light curing times (once, twice, and three times the manufacturer's recommendations). All samples were polymerized with the light tip 8 mm from the specimen. Knoop microhardness measurements were obtained on the top and bottom surfaces of the sample. Results Conventional and LED polymerization modes resulted in higher hardness means and were statistically different from the high intensity mode in almost all experimental conditions. Tripling manufacturers’ recommended light curing times resulted in higher hardness means; this was statistically different from the other times for all polymerization modes in the bottom surface of specimens. This was also true of the top surface of specimens cured using the high intensity mode but not of conventional and LED modes using any of the chosen curing times. Top surfaces showed higher hardness than bottom surfaces. Conclusions It is important to increase the light curing time and use appropriate light curing devices to polymerize resin composite in deep cavities to maximize the hardness of hybrid composite resins. Citation Aguiar FHB, Braceiro A, Lima DANL, Ambrosano GMB, Lovadino JR. Effect of Light Curing Modes and Light Curing Time on the Microhardness of a Hybrid Composite Resin. J Contemp Dent Pract 2007 September; (8)6:001-008.

Effect of Preheating and Fatiguing on Mechanical Properties of Bulk-fill and Conventional Composite Resin

2019 ◽  
Vol 45 (4) ◽  
pp. 387-395
Author(s):  
AA Abdulmajeed ◽  
TE Donovan ◽  
R Cook ◽  
TA Sulaiman
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Composite Resin ◽  
Statistical Significance ◽  
Composite Resins ◽  
Significant Difference ◽  
Diametral Tensile Strength

Clinical Relevance Bulk-fill composite resins may have comparable mechanical properties to conventional composite resin. Preheating does not reduce the mechanical properties of composite resins. SUMMARY Statement of Problem: Bulk-fill composite resins are increasingly used for direct restorations. Preheating high-viscosity versions of these composites has been advocated to increase flowability and adaptability. It is not known what changes preheating may cause on the mechanical properties of these composite resins. Moreover, the mechanical properties of these composites after mastication simulation is lacking. Purpose: The purpose of this study was to evaluate the effect of fatiguing and preheating on the mechanical properties of bulk-fill composite resin in comparison to its conventional counterpart. Methods and Materials: One hundred eighty specimens of Filtek One Bulk Fill Restorative (FOBR; Bulk-Fill, 3M ESPE) and Filtek Supreme Ultra (FSU; Conventional, 3M ESPE) were prepared for each of the following tests: fracture toughness (International Organization for Standardization, ISO 6872), diametral tensile strength (No. 27 of ANSI/ADA), flexural strength, and elastic modulus (ISO Standard 4049). Specimens in the preheated group were heated to 68°C for 10 minutes and in the fatiguing group were cyclically loaded and thermocycled for 600,000 cycles and then tested. Two-/one-way analysis of variance followed by Tukey Honest Significant Difference (HSD) post hoc test was used to analyze data for statistical significance (α=0.05). Results: Preheating and fatiguing had a significant effect on the properties of both FSU and FOBR. Fracture toughness increased for FOBR specimens when preheated and decreased when fatigued (p=0.016). FOBR had higher fracture toughness value than FSU. Diametral tensile strength decreased significantly after fatiguing for FSU (p=0.0001). FOBR had a lower diametral tensile strength baseline value compared with FSU (p=0.004). Fatiguing significantly reduced the flexural strength of both FSU and FOBR (p=0.011). Preheating had no effect on the flexural strength of either FSU or FOBR. Preheating and fatiguing significantly decreased the elastic modulus of both composite resins equally (p>0.05). Conclusions: Preheating and fatiguing influenced the mechanical properties of composite resins. Both composites displayed similar mechanical properties. Preheating did not yield a major negative effect on their mechanical properties; the clinical implications are yet to be determined.

scholarly journals Polymerization Shrinkage of Five Bulk-Fill Composite Resins in Comparison with a Conventional Composite Resin

2019 ◽  
Author(s):  
Mahdi Abbasi ◽  
Zohreh Moradi ◽  
Mansoureh Mirzaei ◽  
Mohammad Javad Kharazifard ◽  
Samaneh Rezaei
Keyword(s):  
Composite Resin ◽  
Composite Resins ◽  
Light Irradiation ◽  
Metal Ring ◽  
Microscope Slide ◽  
Polymerization Shrinkage ◽  
Dimensional Changes ◽  
Light Curing ◽  
Causes Of Failure

Objectives: The polymerization shrinkage of methacrylate-based composites is among the most important causes of failure of composite restorations. The manufacturers claim that bulk-fill composites have a lower polymerization shrinkage than conventional composites. This study aimed to assess the polymerization shrinkage of five bulk-fill composites in comparison with a conventional composite. Materials and Methods: In this in-vitro experimental study, composite discs (n=30) were fabricated using everX Posterior (EXP), Filtek Bulk-Fill Posterior (FBP), SonicFill 2 (SF2), Tetric N-Ceram Bulk-Fill (TNB), X-tra fil (XF), and Filtek Z250 conventional composite at the center of a metal ring bonded to a microscope slide and were covered with a coverslip. This assembly was transferred to a linear variable differential transformer (LVDT). Light-curing (1200 mW/cm2) was performed from underneath the slide for 30 seconds. The deflecting disc method and LVDT were used to assess the dimensional changes of the samples (indicative of polymerization shrinkage) at 1, 30, 60, and 1800 seconds following the onset of light irradiation. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s test. Results: The groups were significantly different regarding polymerization shrinkage (P<0.002). The polymerization shrinkage of the tested composites following the onset of light irradiation ranged from 0.19 to 3.03. EXP showed a significantly higher polymerization shrinkage than other composites at 30, 60, and 1800 seconds after light irradiation, while XF showed the lowest polymerization shrinkage at the aforementioned time points. Conclusions: The tested bulk-fill composites had a polymerization shrinkage similar to that of the conventional composite.

scholarly journals Influence of composite resin volume and C-factor on the polymerization shrinkage stress

2016 ◽  
Vol 19 (2) ◽  
pp. 72 ◽  
Author(s):  
Rafael Francisco Lia Mondelli ◽  
Marilia Mattar de Amoêdo Campos Velo ◽  
Rafael Simões Gonçalves ◽  
Bhenya Ottoni Tostes ◽  
Sergio Kiyoshi Ishikiriama ◽  
...  
Keyword(s):  
Composite Resin ◽  
In Vitro Study ◽  
Composite Resins ◽  
Steel Plates ◽  
Shrinkage Stress ◽  
Lower Stress ◽  
Polymerization Shrinkage ◽  
Light Curing ◽  
Clinical Problems

<p>Objective: Composite polymerization shrinkage<br />stress is an inherent process of chemical and light<br />composite resin activation. Consequently, this fact has<br />been associated to potential clinical problems. The<br />aim of the present in vitro study was to evaluate the<br />volume and C-factor influence on chemical and lightcuring<br />composite resin polymerization shrinkage<br />stress, using a non-rigid method that thereby provides<br />lower stress values, causing a minimal deflection in<br />load cell. Materials and Methods: The contraction<br />forces of the Z-250 and Concise composite resins<br />during polymerization were recorded in an UTM in<br />two experiments. In the first experiment, the Z-250<br />composite was inserted beetwen two rectangular<br />steel plates (6.0 x 2.0 mm), varyng the resin volumes<br />and C-factors, in a single increment, polymerized for<br />20 s and the forces generated were recorded for 120<br />s. In the second experiment, a pair of rectangular steel<br />plates (3x2mm) and two square steel plates (2x2mm),<br />with varied heights (2; 3 mm, respectively), were<br />used to determine the C-factor (0.6; 0.3) influence.<br />Results: The polymerized Z-250 results showed that<br />the volume variations, independent of the C-factor,<br />had a direct influence on the shrinkage stress,<br />different from the Concise, which was influenced by<br />the C-factor. Conclusion: The present study showed<br />that a higher volume of composite resins determines<br />an increase in the shrinkage stress of light-curing<br />composites.</p><p><strong>Keywords</strong></p><p>C-factor. Composite resin. Polymerization. Shrinkage<br />stress.</p>

scholarly journals TiO2 and PEEK Reinforced 3D Printing PMMA Composite Resin for Dental Denture Base Applications

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1049 ◽  
Author(s):  
Sheng-Gui Chen ◽  
Junzhong Yang ◽  
Yong-Guang Jia ◽  
Bingheng Lu ◽  
Li Ren
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Composite Resin ◽  
Blood Compatibility ◽  
Three Dimensional ◽  
Antibacterial Properties ◽  
Dental Restoration ◽  
Composite Resins ◽  
Denture Base ◽  
Light Curing

The future of manufacturing applications in three-dimensional (3D) printing depends on the improvement and the development of materials suitable for 3D printing technology. This study aims to develop an applicable and convenient protocol for light-curing resin used in 3D industry, which could enhance antibacterial and mechanical properties of polymethyl methacrylate (PMMA) resin through the combination of nano-fillers of surface modified titanium dioxide (TiO2) and micro-fillers of polyetheretherketone (PEEK). PMMA-based composite resins with various additions of TiO2 and PEEK were prepared and submitted to characterizations including mechanical properties, distribution of the fillers (TiO2 or/and PEEK) on the fractured surface, cytotoxicity, antibacterial activity, and blood compatibility assessment. These results indicated that the reinforced composite resins of PMMA (TiO2-1%-PEEK-1%) possessed the most optimized properties compared to the other groups. In addition, we found the addition of 1% of TiO2 would be an effective amount to enhance both mechanical and antibacterial properties for PMMA composite resin. Furthermore, the model printed by PMMA (TiO2-1%-PEEK-1%) composite resin showed a smooth surface and a precise resolution, indicating this functional dental restoration material would be a suitable light-curing resin in 3D industry.

scholarly journals Benefit of Glycerine on Surface Hardness of Hybrid & Nanofill Resin Composite

2021 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Ferriza Tri Mardianti ◽  
Sukaton Sukaton ◽  
Galih Sampoerno
Keyword(s):  
Free Radicals ◽  
Composite Resin ◽  
Resin Composite ◽  
Surface Hardness ◽  
Composite Resins ◽  
Polymerization Process ◽  
Tooth Structure ◽  
Significant Difference ◽  
Light Curing ◽  
Composite Resin Restorations

Background: Composite resins restoration is a treatment for tooth structure loss due to pathological conditions. Longevity of composite resins restoration can be affected by surface hardness restoration. Glycerin can increase surface hardness restoration with inhibit bond oxygen and free radicals on polymerization composite resins. Purpose: Analyze the increase surface hardness composite resins restoration after glycerin application before light-curing composite resins. Review(s): Of the six journals included in this literature review, five journals reported significant differences because of the obstacles in the polymerization process of the composite resin when composite contact with light-curing will activate the photoinitiator to produce highly reactive free radicals, free radicals will break the double chain carbon bonds of monomers and form single bonds of free radicals with monomers. Bonding of free radicals with monomers will produce polymeric bonds (degree of conversion) which affects the level of surface hardness of the filling. While one journal noted no significant difference in the surface hardness of composite resin after glycerin application. Conclusion: The use of glycerin before light-curing can increase the surface hardness composite resin restorations.

scholarly journals Curing Depth and Degree of Conversion of Five Bulk-Fill Composite Resins Compared to a Conventional Composite

2019 ◽  
Vol 13 (1) ◽  
pp. 422-429
Author(s):  
Samaneh Rezaei ◽  
Mehdi Abbasi ◽  
Farzaneh Sadeghi Mahounak ◽  
Zohreh Moradi
Keyword(s):  
Mean Value ◽  
Composite Resins ◽  
Degree Of Conversion ◽  
Bottom Surface ◽  
Hardness Tester ◽  
Three Samples ◽  
Light Curing ◽  
The Difference ◽  
Bottom To Top

Background: Limited curing depth and its effect on the degree of conversion are among the challenges of working with light-cure composite resins. The use of bulk-fill composites is one strategy to overcome these limitations. Methods: Ever X Posterior (EXP), Filtek Bulk-Fill Posterior (FBP), Sonic Fill 2 (SF2), Tetric N-Ceram Bulk-Fill (TNB), and X-tra Fil (XF) bulk-fill and Filtek Z250 conventional composite were evaluated in this in vitro experimental study. Six samples for the assessment of microhardness and three samples for the evaluation of DC were fabricated of each composite. After light curing and polishing, the samples were incubated at 37°C for 24 hours. Microhardness was measured by a Vickers hardness tester three times and the mean value was calculated. DC of the top and bottom surfaces was determined using Fourier-Transform Infrared Spectroscopy (FTIR). Data were analyzed using one-way ANOVA and Tukey’s test. Results: Microhardness and DC were significantly different among the groups (P<0.001). XF and Z250 equally showed the highest bottom-to-top surface microhardness ratio (0.97 ± 0.01) and significantly higher DC in the top (P<0.001) and bottom (P<0.005) surfaces compared to other groups. TNB showed the lowest microhardness ratio (0.88 ± 0.04) and DC (68.66 ± 1.52 and 61.00 ± 2.00); the difference in DC of the bottom surface was statistically significant (P<0.003). Conclusion: It appears that bulk-fill composites evaluated in this study are adequately polymerized at 4 mm depth. Their DC was optimal and within the range of conventional composites.

scholarly journals Impact of refrigeration on the surface hardness of hybrid and microfilled composite resins

2009 ◽  
Vol 20 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Fernando Henrique Ruppel Osternack ◽  
Danilo Biazzetto de Menezes Caldas ◽  
Rodrigo Nunes Rached ◽  
Sérgio Vieira ◽  
Jeffrey A. Platt ◽  
...  
Keyword(s):  
Room Temperature ◽  
Surface Hardness ◽  
In Vitro Study ◽  
Knoop Hardness ◽  
Composite Resins ◽  
Bottom Surface ◽  
Steel Mold ◽  
Polymerization Condition ◽  
Post Hoc

This in vitro study evaluated the Knoop hardness of the composite resins Charisma® (C) and Durafill VS® (D) polymerized in 3 different conditions: at room temperature (A) (23 ± 1°C); refrigerated at 4 ± 1°C and immediately photo-activated after removal from the refrigerator (0); and, refrigerated at 4 ± 1°C and photo-activated after a bench time of 15 min at room temperature (15). One hundred and twenty specimens (4 mm diameter and 2 mm depth) were made using a stainless steel mold and following manufacturer's instructions. All specimens were tested immediately after polymerization (I) and after 7 days of water storage in the dark at room temperature (7d). The data were subjected to ANOVA and post-hoc Tukey's test (a=0.05). On the top surface, CAI was statistically similar to C15I and DAI to D15I (p>0.05). On the bottom surface, CAI presented higher hardness values when compared to COI and C15I (p<0.05). The D groups showed no significant differences (p>0.05) on the bottom surfaces for any tested polymerization condition. After 7 days of storage, the Knoop hardness decreased significantly (p<0.05) for groups C7d and D7d except for C07d, which was not different from COI at either surface (p>0.05). D07d showed higher Knoop hardness (p<0.05) values on the top surface when compared to the other groups.

Effects of Cyclic Stress on the Mechanical Properties of Cultured Collagen Fascicles from the Rabbit Patellar Tendon

2003 ◽  
Vol 125 (6) ◽  
pp. 893-901 ◽  
Author(s):  
Ei Yamamoto ◽  
Susumu Tokura ◽  
Kozaburo Hayashi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Patellar Tendon ◽  
Control Level ◽  
Quadratic Function ◽  
Peak Stress ◽  
Cyclic Stress ◽  
Original Strength

Effects of cyclic stress on the mechanical properties of collagen fascicles were studied by in vitro tissue culture experiments. Collagen fascicles (approximately 300 μm in diameter) obtained from the rabbit patellar tendon were applied cyclic load at 4 Hz for one hour per day during culture period for one or two weeks, and then their mechanical properties were determined using a micro-tensile tester. There was a statistically significant correlation between tensile strength and applied peak stress in the range of 0 to 5 MPa, and the relation was expressed by a quadratic function. The maximum strength (19.4 MPa) was obtained at the applied peak stress of 1.8 MPa. The tensile strength of fascicles were within a range of control values, if they were cultured under peak stresses between 1.1 and 2.6 MPa. Similar results were also observed in the tangent modulus, which was maintained at control level under applied peak stresses between 0.9 and 2.8 MPa. The stress of 0.9 to 1.1 MPa is equivalent to approximately 40% of the in vivo peak stress which is developed in the intact rabbit patellar tendon by running, whereas that of 2.6 to 2.8 MPa corresponds to approximately 120% of the in vivo peak stress. Therefore, the fascicles cultured under applied peak stresses of lower than 40% and higher than 120% of the in vivo peak stress do not keep the original strength and modulus. These results indicate that the mechanical properties of cultured collagen fascicles strongly depend upon the magnitude of the stress applied during culture, which are similar to our previous results observed in stress-shielded and overstressed patellar tendons in vivo.

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