Evaluation of shear bond strengths of gingiva-colored composite resin to porcelain, metal and zirconia substrates

Hong-Seok An,Ji-Man Park,Eun-Jin Park 대한치과보철학회 2011 The Journal of Advanced Prosthodontics Vol.3 No.3

PURPOSE The purpose of this study is to evaluate and compare the shear bond strength of the gingiva-colored composite resin and the toothcolored composite resin to porcelain, metal and zirconia. MATERIALS AND METHODS Sixty cylindrical specimens were fabricated and divided into the following 6 groups (Group 1-W: tooth-colored composite bonded to porcelain, Group 1-P: gingiva-colored composite bonded to porcelain, Group 2-W: tooth-colored composite bonded to base metal, Group 2-P: gingiva-colored composite bonded to base metal, Group 3-W: toothcolored composite bonded to zirconia, Group 3-P: gingiva-colored composite bonded to zirconia). The shear bond strength was measured with a universal testing machine after thermocycling and the failure mode was noted. All data were analyzed using the two-way analysis of variance test and the Bonferroni post-hoc test at a significance level of 0.05. RESULTS The mean shear bond strength values in MPa were 12.39, 13.42, 8.78, 7.98, 4.64 and 3.74 for Group 1-W, 1-P, 2-W, 2-P, 3-W and 3-P, respectively. The difference between the two kinds of composite resin was not significant. The shear bond strength of Group 1 was the highest and that of Group 3 was the lowest. The differences among Group 1, 2 and 3 were all significant (P<.05). CONCLUSION The shear bond strength of the gingiva-colored composite was not less than that of the tooth-colored composite. Thus, repairing or fabricating ceramic restorations using the gingiva-colored composite resin can be regarded as a practical method. Especially, the prognosis would be fine when applied on porcelain surfaces.

A 3-year retrospective study of clinical durability of bulk-filled resin composite restorations

Ugurlu Muhittin,Sari Fatmanur 대한치과보존학회 2022 Restorative Dentistry & Endodontics Vol.47 No.1

Objectives This study aimed to assess the clinical longevity of a bulk-fill resin composite in Class II restorations for 3-year. Materials and Methods Patient record files acquired from the 40 patients who were treated due to needed 2 similar sizes Class II composite restorations were used for this retrospective study. In the experimental cavity, the flowable resin composite SDR was inserted in the dentinal part as a 4 mm intermediate layer. A 2 mm coverage layer with a nano-hybrid resin composite (CeramX) was placed on SDR. The control restoration was performed by an incremental technique of 2 mm using the nano-hybrid resin composite. The restorations were blindly assessed by 2 calibrated examiners using modified United States Public Health Service criteria at baseline and 1, 2, and 3 years. The data were analyzed using non-parametric tests (p = 0.05). Results Eighty Class II restorations were evaluated. After 3-years, 4 restorations (5%) failed, 1 SDR + CeramX, and 3 CeramX restorations. The annual failure rate (AFR) of the restorations was 1.7%. The SDR + CeramX group revealed an AFR of 0.8%, and the CeramX group an AFR of 2.5% (p > 0.05). Regarding anatomical form and marginal adaptation, significant alterations were observed in the CeramX group after 3-years (p < 0.05). The changes in the color match were observed in each group over time (p < 0.05). Conclusions The use of SDR demonstrated good clinical durability in deep Class II resin composite restorations. Objectives This study aimed to assess the clinical longevity of a bulk-fill resin composite in Class II restorations for 3-year. Materials and Methods Patient record files acquired from the 40 patients who were treated due to needed 2 similar sizes Class II composite restorations were used for this retrospective study. In the experimental cavity, the flowable resin composite SDR was inserted in the dentinal part as a 4 mm intermediate layer. A 2 mm coverage layer with a nano-hybrid resin composite (CeramX) was placed on SDR. The control restoration was performed by an incremental technique of 2 mm using the nano-hybrid resin composite. The restorations were blindly assessed by 2 calibrated examiners using modified United States Public Health Service criteria at baseline and 1, 2, and 3 years. The data were analyzed using non-parametric tests (p = 0.05). Results Eighty Class II restorations were evaluated. After 3-years, 4 restorations (5%) failed, 1 SDR + CeramX, and 3 CeramX restorations. The annual failure rate (AFR) of the restorations was 1.7%. The SDR + CeramX group revealed an AFR of 0.8%, and the CeramX group an AFR of 2.5% (p > 0.05). Regarding anatomical form and marginal adaptation, significant alterations were observed in the CeramX group after 3-years (p < 0.05). The changes in the color match were observed in each group over time (p < 0.05). Conclusions The use of SDR demonstrated good clinical durability in deep Class II resin composite restorations.

Effect of bioactive glass-containing resin composite on dentin remineralization

Jang, Ji-Hyun,Lee, Myoung Geun,Ferracane, Jack L.,Davis, Harry,Bae, Han Eul,Choi, Dongseok,Kim, Duck-Su Elsevier 2018 Journal of dentistry Vol.75 No.-

<P><B>Abstract</B></P> <P><B>Objectives</B></P> <P>The purpose of this study was to evaluate the effect of bioactive glass (BAG)-containing composite on dentin remineralization.</P> <P><B>Methods</B></P> <P>Sixty-six dentin disks with 3 mm thickness were prepared from thirty-three bovine incisors. The following six experimental groups were prepared according to type of composite (control and experimental) and storage solutions (simulated body fluid [SBF] and phosphate-buffered saline [PBS]): 1 (undemineralized); 2 (demineralized); 3 (demineralized with control composite in SBF); 4 (demineralized with control composite in PBS); 5 (demineralized with experimental composite in SBF); and 6 (demineralized with experimental composite in PBS). BAG65S (65% Si, 31% Ca, and 4% P) was prepared via the sol-gel method. The control composite was made with a 50:50 Bis-GMA:TEGDMA resin matrix, 57 wt% strontium glass, and 15 wt% aerosol silica. The experimental composite had the same resin and filler, but with 15 wt% BAG65S replacing the aerosol silica. For groups 3–6, composite disks (20 × 10 × 2 mm) were prepared and approximated to the dentin disks and stored in PBS or SBF for 2 weeks. Micro-hardness test, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and field-emission scanning electron microscopy (FE-SEM) was investigated.</P> <P><B>Results</B></P> <P>The BAG-containing composite significantly increased the micro-hardness of the adjacent demineralized dentin. ATR-FTIR revealed calcium phosphate peaks on the surface of the groups which used BAG-containing composite. FE-SEM revealed surface deposits partially occluding the dentin surface. No significant difference was found between SBF and PBS storage.</P> <P><B>Clinical Significance</B></P> <P>Bioactive glass is a potentially useful material for remineralization of tooth structure. When incorporated into a resin composite, it may aid in remineralizing the adjacent demineralized dentin, thus preventing further destruction of the tooth.</P> <P><B>Conclusion</B></P> <P>BAG-containing composites placed in close proximity can partially remineralize adjacent demineralized dentin.</P>

A COMPARATIVE STUDY BETWEEN DEGREE OF CONVERSION AND FLEXURAL STRENGTH OF COMPOSITE RESINS

Lee Seong-Hee,Pae Ahran,Kim Sung-Hun The Korean Academy of Prosthodonitics 2006 대한치과보철학회지 Vol.44 No.3

Statement of problem. Although many studies have been carried out to investigate the correlation between the degree of conversion and the flexural strength of composite resins, there is minimal information in the literature attempting to compare degree of conversion, flexural strength and their correlation between restorative composite resins and flowable composite resins. Purpose. The purposes of this study were to measure the degree of conversion and flexural strength of composite resins with different rheological behavior and to correlate the two properties. Materials and methods. Four restorative (Vit-1-escence, Z-250, Tetric ceram, Esthet-X) and four flowable (Aeliteflo, Admiraflow, Permaflo, Revolution) light-curing composite resins were investigated. The degree of conversion(DC) was analyzed with Fourier transfer infra-red spectroscopy(FTIR) spectrum by a potassium bromide(KBr) pellet transmission method. The spectrum of the unpolymerized specimen had been measured before the specimen was irradiated for 60s with a visible light curing unit. The Poiymerized specimen was scanned for its in spectrum. The flexural strength(FS) was measured with 3-point bending test according to ISO 4049 after storage in water at $37^{\circ}C$ for 24 hours. The data were statistically analyzed by an independent sample t-test and one-way ANOVA at the significance level of 0.05. The dependence of flexural strength on the degree of conversion was also analyzed by regression analysis. Results. Mean DC and FS values ranged from 43% to 61% and from 84.7MPa to 156.7MPa respectively. DC values of the flowable composite resins were significantly higher than those of restorative composite resins (P < 0.05). The FS values of restorative composite resins were greater than those of flowable composite resins. No statistically significant correlation was observed between the DC and the FS tested in any of the composites. The dependence of FS on DC in restorative or flowable composite resins was not significant. Conclusion. It can be concluded that radical polymerization of the organic matrix is not a major factor in determining flexural strength of the commercially available composite resins.

Evaluation and Comparison of Mechanical Properties of Natural Fiber Abaca-sisal Composite

K. Venkatesan,G. B. Bhaskar 한국섬유공학회 2020 Fibers and polymers Vol.21 No.7

With the high usage of the synthetic fiber, the amount of the waste materials has increased as the degradationprocess is quite slow and with the burning of the synthetic fibers creates toxic gas and other environmental hazards.Presentlynatural fibershas many implications like low density, cheap, high specific properties, non-abrasive and less harmful duringmanufacturing and most importantly the abundance in nature and can be made by planting. Because of which it is giving agood run compare to conventional glass and carbon fibers composites. The glass fiber composite is replaced by natural fibercomposites for environmental sustainability. Fiber extracted from plants is renewable and low levels of embodied energycompared to synthetic fibers. This paper deals with comparison of mechanical properties of a hybrid composite (abaca +sisal) and comparing the results with the ABAQUS simulation results. This hybrid composite consists of three layers with topand bottom layers of sisal fibers and the middle layer is made up of abaca fiber. These hybrid composites (sisal + abaca) werefabricated with different orientations (0 °, 45 °, 90 °) of fiber. The above said composite is fabricated by using hand layupmethod. Epoxy resin along with Huntsman Resin 951 hardener was used as the binding agent throughout the layer. Theultimate tensile strength and percentage elongation of the composite were 90 ° oriented fiber composite is found to be highervalue compared to 0 °, 45 ° oriented fiber. Flexural strength of the composite was 45 °, 90 ° orientedfiber composite havingsame value, whereas 0 ° fiber-oriented composite having least value. The ultimate shear strength of composite was 45 °oriented fiber composite is found to be higher value compare to the other two oriented fiber composites (90 °, 0 °). Thebreaking load of composite 0 ° oriented fiber composite is high value compareto the other two oriented fiber composites(45 °, 90 °). Scanning electron microscope is used to analyse the internal structural of the broken specimen.

Phenyl silane treatment and carding process to improve the mechanical, thermal, and water-absorption properties of regenerated cellulose lyocell/polylactic acid bio-composites

Park, Ji-Won,Lee, Tae-Hyung,Back, Jong-Ho,Jang, Seong-Wook,Kim, Hyun-Joong,Skrifvars, Mikael Elsevier Science Ltd 2019 Composites Part B, Engineering Vol.167 No.-

<P><B>Abstract</B></P> <P>We fabricated a new composite material with increased lyocell (a form of rayon that consists of cellulose fiber made from dissolving wood pulp) content through a surface hydrophobic treatment using phenyl silane and fiber carding/melt pressing. A matrix of polylactic acid (PLA) was used to enhance the environment-friendly properties of the composite and a carding process was used to orient the fibers in the composite. The lyocell content was controlled from 10% to 90%. Cross direction (CD) and machine direction (MD) samples were prepared to confirm the effect of the fiber directionality of the composite on its mechanical properties. The MD samples performed better than the CD samples. The tensile, flexural, and impact strengths of the composite were increased by approximately 85%, 155%, and 55%, respectively, after surface treatment. In the heat-resistance evaluation, confirmed by pyrolysis, surface treatment showed an average improvement of more than 10 °C. The water-absorption characteristics showed dramatic improvement, with enhanced surface-wetting properties and excellent initial moisture-absorption properties in the immersion test. Based on the comprehensive results, we conclude that the performance of the composite was satisfactory even when the content of lyocell was 50% or more.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This paper deals with the development of environmentally friendly green composite materials using regenerated cellulose Lyocell and PLA fibers. </LI> <LI> By using carding/melt pressing process technology, it was possible to obtain lyocell rich composite material. </LI> <LI> Phenyl silane surface treatment technology is very effective in improving internal bonding strength of composite materials. </LI> <LI> Through directional control, composite with very good strength in mechanical direction were produced. </LI> <LI> Mechanical properties, heat resistance and water resistance tend to increase with surface treatment. </LI> <LI> This technology will be a good example to maximize the content of naturally based fillers. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Color discrepancy of single-shade composites at different distances from the interface measured using cell phone images

Santana Márcia Luciana Carregosa,Livi Gabriella de Jesus Santos,Faria-e-Silva André Luis 대한치과보존학회 2024 Restorative Dentistry & Endodontics Vol.49 No.1

Objectives This study aimed to evaluate the impact of substrate color and interface distance on the color adjustment of 2 single-shade composites, Vittra APS Unique and Charisma Diamond One. Materials and Methods Dual disc-shaped specimens were created using Vittra APS Unique or Charisma Diamond One as the center composite, surrounded by shaded composites (A1 or A3). Color measurements were taken with a spectrophotometer against a gray background, recording the color coordinates in the CIELAB color space. Illumination with a light-correcting device and image acquisition using a polarizing filter-equipped cell phone were performed on specimens over the same background. Image processing software was used to measure the color coordinates in the center and periphery of the inner composite and in the outer composite. The color data were then converted to CIELAB coordinates and adjusted using data from the spectrophotometer. Color differences (ΔE00) between the center/periphery of single-shade and outer composites were calculated, along with color changes in single-shade composites caused by different outer composites. Color differences for the inner composites surrounded by A1 and A3 were also calculated. Data were analyzed using repeated-measures analysis of variance (α = 0.05). Results The results showed that color discrepancies were lowest near the interface and when the outer composite was whiter (A1). Additionally, Charisma Diamond One exhibited better color adjustment ability than Vittra APS Unique. Conclusions Color discrepancies between the investigated single-shade composites diminished towards the interface with the surrounding composite, particularly when the latter exhibited a lighter shade. Objectives This study aimed to evaluate the impact of substrate color and interface distance on the color adjustment of 2 single-shade composites, Vittra APS Unique and Charisma Diamond One. Materials and Methods Dual disc-shaped specimens were created using Vittra APS Unique or Charisma Diamond One as the center composite, surrounded by shaded composites (A1 or A3). Color measurements were taken with a spectrophotometer against a gray background, recording the color coordinates in the CIELAB color space. Illumination with a light-correcting device and image acquisition using a polarizing filter-equipped cell phone were performed on specimens over the same background. Image processing software was used to measure the color coordinates in the center and periphery of the inner composite and in the outer composite. The color data were then converted to CIELAB coordinates and adjusted using data from the spectrophotometer. Color differences (ΔE00) between the center/periphery of single-shade and outer composites were calculated, along with color changes in single-shade composites caused by different outer composites. Color differences for the inner composites surrounded by A1 and A3 were also calculated. Data were analyzed using repeated-measures analysis of variance (α = 0.05). Results The results showed that color discrepancies were lowest near the interface and when the outer composite was whiter (A1). Additionally, Charisma Diamond One exhibited better color adjustment ability than Vittra APS Unique. Conclusions Color discrepancies between the investigated single-shade composites diminished towards the interface with the surrounding composite, particularly when the latter exhibited a lighter shade.

Effect of vibration on adaptation of dental composites in simulated tooth cavities

한선희,이인복 한국유변학회 2018 Korea-Australia rheology journal Vol.30 No.4

This research investigated the effects of vibration on the rheological properties of dental composites and the adaptation of tooth cavity-composite interfaces. A portable vibratory packing device and two composites, micro-hybrid dental composite (MC) and nano-hybrid dental composite (NC), were evaluated. The frequency and amplitude of the vibratory packing device were measured. Dynamic oscillatory shear tests were conducted with varying frequency to examine the rheological properties of the composites. Twenty identical composite teeth with a Class I cavity were prepared and filled with one of the two composites. The composite was placed into a cavity using the vibratory packing device operating in either ON or OFF mode. After light-curing of the composite, the gap between the tooth and the composite was evaluated using micro-computed tomography. Two-way ANOVA was used to evaluate the effects of vibration and composite type on tooth-composite adaptation. The frequency of the vibratory packing device was 66.8 Hz. The complex viscosity, η*, of NC was higher than that of MC, and η* of both composites significantly decreased with increasing oscillation frequency. However, the application of vibration did not enhance adaptation at the tooth-composite interface.

Influence of Lactic Acid-Grafted Multi-Walled Carbon Nanotube (LA-g-MWCNT) on the Electrical and Rheological Properties of Polycarbonate/Poly(lactic acid)/ LA-g-MWCNT Composites

장명근,김우년,이윤균 한국고분자학회 2015 Macromolecular Research Vol.23 No.10

The effects of lactic acid-grafted multi-walled carbon nanotube (LA-g-MWCNT) on the electrical and rheological properties of the polycarbonate (PC)/poly(lactic acid) (PLA)/LA-g-MWCNT composite were studied. To increase dispersion of the conductive filler in the PC/PLA (70/30) blend, chemically-modified MWCNT, which is LA-g-MWCNT, was used as a compatibilizer between the conductive filler and polymers. For the PC/PLA/LAg- MWCNT composite, the increased values of the electrical conductivity, electromagnetic interference shielding effectiveness, and complex viscosity were observed compared to those of PC/PLA/MWCNT composite. The results suggested that the increased dispersion of the LA-g-MWCNT in the PC/PLA (70/30) blend is caused by increased connectivity of the MWCNT-MWCNT network structure of the composite. The interfacial tension of the PLA/ MWCNT composite was lower than that of the PC/MWCNT composite. The lower value of interfacial tension of the PLA/MWCNT composite affected the dispersion of the MWCNT in the PLA phase (dispersed phase) more than in the PC phase (continuous phase). After hydrolysis, the PC/PLA/LA-g-MWCNT composite showed higher electrical conductivity than the PC/PLA/MWCNT composites. As a result, it is suggested that the increased dispersion of the LA-g-MWCNT in the PC/PLA blend has affected the increase in the electrical conductivity and lowering of the hydrolytic degradation of the PC/PLA/LA-g-MWCNT composite compared to the PC/PLA/MWCNT composite.

Preparation and properties on the graphite/polypropylene composite bipolar plates with a 304 stainless steel by compression molding for PEM fuel cell

Lee, Yang-Bok,Lee, Choong-Hyun,Kim, Kyung-Min,Lim, Dae-Soon Elsevier 2011 International journal of hydrogen energy Vol.36 No.13

<P><B>Abstract</B></P><P>Graphite/polymer composites have high corrosion resistance, low contact resistance and low fabrication cost but low cell efficiency and mechanical strength. This study examined the electrical and mechanical properties of graphite/polypropylene composite bipolar plates. Carbon nanotubes (CNTs) were used to improve the electrical properties of the graphite/PP composites. Although the electrical properties increased when excess conducting filler was added to the composite, the mechanical strength decreased significantly. 304 stainless steel (304 SS) plates with different thicknesses were used as the support material of a graphite/PP composite bipolar plate. The 304 SS-supported graphite/PP composite bipolar plate had an optimum CNTs/graphite/PP composite composition of 1.2, 83 and 17 wt.%, respectively. The flexural strength of the 304 SS-supported graphite/PP composites increased from 35 to 58 MPa with increasing 304 SS thickness from 0.5 to 1 mm. The power density of the graphite bipolar plate and 304 SS-supported graphite/PP composite bipolar plate were 968 and 877 mW cm<SUP>−2</SUP>, respectively. The 304 SS complemented the mechanical strength of the graphite/PP composite bipolar plate as well as the cell efficiency.</P> <P><B>Highlights</B></P><P>► The 304 SS-supported graphite/PP composite bipolar plate was fabricated by conventional compression molding method. ► 304 SS plates with different thicknesses were used as the support material of a graphite/PP composite bipolar plate. ► The electrical, mechanical and corrosional properties and single cell performance were evaluated. ► The 304 SS improved the mechanical strength of the graphite/PP composite bipolar plate as well as the cell efficiency.</P>