scholarly journals Adherence of Streptococcus mutans to Fiber-Reinforced Filling Composite and Conventional Restorative Materials

2009 ◽  
Vol 3 (1) ◽  
pp. 227-232 ◽  
Author(s):  
Lippo V.J Lassila ◽  
Sufyan Garoushi ◽  
Johanna Tanner ◽  
Pekka K Vallittu ◽  
Eva Söderling
Keyword(s):  
Surface Roughness ◽  
Streptococcus Mutans ◽  
Polymer Matrix ◽  
Bacterial Adhesion ◽  
Glass Fibers ◽  
Composite Resins ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Restorative Materials

Objectives. The aim was to investigate the adhesion of Streptococcus mutans (S. mutans) to a short glass fibers reinforced semi-IPN polymer matrix composite resin. The effect of surface roughness on adhesion was also studied. For comparison, different commercial restorative materials were also evaluated. Materials and Methods. Experimental composite FC resin was prepared by mixing 22.5 wt% of short E-glass fibers, 22.5 wt% of IPN-resin and 55 wt% of silane treated silica fillers using high speed mixing machine. Three direct composite resins (Z250, Grandio and Nulite), resin-modified glass ionomers (Fuji II LC), amalgam (ANA 2000), fiber-reinforced composite (FRC) (everStick and Ribbond), and pre-fabricated ceramic filling insert (Cerana class 1) were tested in this study. Enamel and dentin were used as controls. The specimens (n=3/group) with or without saliva were incubated in a suspension of S. mutans allowing initial adhesion to occur. For the enumeration of cells on the disc surfaces as colony forming units (CFU) the vials with the microbe samples were thoroughly Vortex-treated and after serial dilutions grown anaerobically for 2 days at +37°C on Mitis salivarius agars (Difco) containing bacitracin. Bacterial adhesion was also evaluated by using scanning electron microscopy. Surface roughness (Ra) of the materials was also determined using a surface profilometer. All results were statistically analyzed with one-way analysis of variance (ANOVA). Results. Composite FC resin and other commercial restorative materials showed similar adhesion of S. mutans, while adhesion to dentin and enamel was significantly higher (p<0.05). Surface roughness had no effect on bacterial adhesion. Saliva coating significantly decreased the adhesion for all materials (p<0.05). Composite FC resin had a significantly higher Ra value than control groups (p<0.05). Conclusions. Short fiber-reinforced composite with semi-IPN polymer matrix revealed similar S. mutans adhesion than commercial restorative materials.

scholarly journals The Effect of Surface Roughness on Repair Bond Strength of Light-Curing Composite Resin to Polymer Composite Substrate

2013 ◽  
Vol 7 (1) ◽  
pp. 126-131 ◽  
Author(s):  
Timo T. Kallio ◽  
Arzu Tezvergil-Mutluay ◽  
Lippo V.J. Lassila ◽  
Pekka K. Vallittu
Keyword(s):  
Surface Roughness ◽  
Bond Strength ◽  
Polymer Matrix ◽  
Shear Bond Strength ◽  
Weibull Modulus ◽  
Composite Resin ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Particulate Filler

Objective: The purpose of this study was to analyze the shear bond strength of a new composite resin to polymer-based composite substrates using various surface roughnesses and two kinds of polymer matrices. Materials and methods: Particulate filler composite resin with cross-linked polymer matrix and fiber-reinforced composite with semi-interpenetrating polymer matrix were used as bonding substrates after being ground to different roughnesses. Substrates were aged in water for one week before bonding to new resin composites. Twelve specimens in the substrate groups were ground with grinding papers of four grits; 320, 800, 1200 and 2400. Results: Corresponding values of surface roughness (Ra) varied from 0.09 to 0.40 for the particulate filler composite resin and 0.07 to 0.96 for the fiber-reinforced composite resin. Characteristic shear bond strength between the new resin and particulate filler composite resin was highest (27.8 MPa) with the roughest surface (Weibull modulus: 2.085). Fiber-reinforced composite showed the highest bond strength (20.8 MPa) with the smoothest surface (Weibull modulus: 4.713). Conclusions: We concluded that surface roughness did not increase the bonding of new resin to the substrate of IPN based fiber-reinforced composite, whereas the roughness contributed to bonding the new resin to the particulate filler composite resin with a cross-linked polymer matrix.

scholarly journals Antibacterial coating on biocomposites for cranio-facial reconstruction

2016 ◽  
Vol 89 (3) ◽  
pp. 430-434 ◽  
Author(s):  
Madalina Anca Lazar ◽  
Dan Vodnar ◽  
Doina Prodan ◽  
Horatiu Rotaru ◽  
Calin Rares Roman ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Bacterial Adhesion ◽  
Inhibition Zone ◽  
Fiber Reinforced ◽  
Bacterial Strains ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Craniofacial Implants ◽  
Systemic Antibiotics

Background and aims. Despite the fact that implants are sterilized, antiseptic techniques are applied and systemic antibiotics are routinely administered prior to and after craniofacial surgery, infection rates between 3% and 40% are still reported for alloplastic implants, urging for implant removal. The present study focuses on the development of a fiber-reinforced composite (FRC) implant for craniofacial reconstruction with antimicrobial properties.Methods. A new fiber-reinforced composite coated with gentamicin was developed and tested for bacterial adherence and antibacterial efficiency, using two of the most involved bacterial strains in the postoperative infections: Staphylococcus aureus and Pseudomonas aeruginosa.Results. Bacteria were efficiently inactivated in direct contact with gentamicin coatings (p<0.05). The inhibition zone for Staphylococcus aureus ranged from 17.21 mm to 20.13 mm and for Pseudomonas aeruginosa ranged from 12.93 mm to 15.33 mm. Although no significant statistical results were found for bacterial adhesion and gentamicin concentration, (Staphylococcus aureus: β= -0.974; p=0.144>0.05 and Pseudomonas aeruginosa: β = -0.921; p=0.255>0.05), a negative relation was observed, indicating the reversed relation between the antibiotic dosage and the bacterial adherence.Conclusion. The results of the two applied microbiological protocols used in the study suggested that gentamicin eluting coating inhibited not only the bacterial growth, but also led to a lower initial bacterial adhesion to the surface of the implant. Thus, antibiotic coating of craniofacial implants may reduce the infection rate related to reconstructive surgery.

Shear Lag Model for Regularly Staggered Short Fuzzy Fiber Reinforced Composite

2014 ◽  
Vol 81 (9) ◽  
Author(s):  
S. I. Kundalwal ◽  
M. C. Ray ◽  
S. A. Meguid
Keyword(s):  
Polymer Matrix ◽  
Interfacial Shear Stress ◽  
Stress Transfer ◽  
Fiber Reinforced ◽  
Shear Lag ◽  
Fiber Reinforced Composite ◽  
Shear Lag Model ◽  
Transfer Characteristics ◽  
Reinforced Composite ◽  
Lag Model

In this article, we investigate the stress transfer characteristics of a novel hybrid hierarchical nanocomposite in which the regularly staggered short fuzzy fibers are interlaced in the polymer matrix. The advanced fiber augmented with carbon nanotubes (CNTs) on its circumferential surface is known as “fuzzy fiber.” A three-phase shear lag model is developed to analyze the stress transfer characteristics of the short fuzzy fiber reinforced composite (SFFRC) incorporating the staggering effect of the adjacent representative volume elements (RVEs). The effect of the variation of the axial and lateral spacing between the adjacent staggered RVEs in the polymer matrix on the load transfer characteristics of the SFFRC is investigated. The present shear lag model also accounts for the application of the radial loads on the RVE and the radial as well as the axial deformations of the different orthotropic constituent phases of the SFFRC. Our study reveals that the existence of the non-negligible shear tractions along the length of the RVE of the SFFRC plays a significant role in the stress transfer characteristics and cannot be neglected. Reductions in the maximum values of the axial stress in the carbon fiber and the interfacial shear stress along its length become more pronounced in the presence of the externally applied radial loads on the RVE. The results from the newly developed analytical shear lag model are validated with the finite element (FE) shear lag simulations and found to be in good agreement.

The Effect of Fiber Position and Polymerization Condition on the Flexural Properties of Fiber-Reinforced Composite

2004 ◽  
Vol 5 (2) ◽  
pp. 14-26 ◽  
Author(s):  
Lippo V.J. Lassila ◽  
Pekka K. Vallittu
Keyword(s):  
Flexural Strength ◽  
Glass Fibers ◽  
Flexural Modulus ◽  
Flexural Properties ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Monomer Content ◽  
Light Curing ◽  
Polymerization Condition

Abstract The aim of this study was to investigate the influence of the position of the fiber rich layer on the flexural properties of fiber-reinforced composite (FRC) construction. In addition, the total residual monomer content of FRC was quantitatively determined to find out the difference of the effectiveness of two types of light-curing units using liquid chromatography (HPLC). Unidirectional continuous E-glass FRC and hybrid particulate filler composite resins were used in the fabrication of test specimens. Four different positions of the FRC layer were used: compression, neutral, tension, and vertical side position. A three-point bending test (ISO 10477) was performed to measure the flexural properties of the specimens. Position of the FRC layer had a significant effect on the flexural strength (p<0.001, ANOVA). Also, the type of light-curing device had an effect on flexural strength (p<0.001). Specimens with FRC positioned on the compression side showed flexural strength of approximately 250 MPa, whereas FRC positioned on the tension side showed strength ranging from 500 to 600 MPa. Mean flexural modulus with FRC placed horizontally ranged between 9-12 GPa; no significant difference was found between these groups. However when fiber reinforcement was positioned vertically, the flexural modulus raised up to 16 GPa. Specimens with 24 vol% glass fibers contained 52% less residual monomer than specimens without glass fibers. The monomer content was lower in specimens polymerized with the curing device with higher polymerization temperature. In order to optimize flexural strength of low fiber volume fraction, the fibers should be placed at the tension side of the specimen. Citation Lassila LVJ, Vallittu PK. The Effect of Fiber Position and Polymerization Condition on the Flexural Properties of Fiber-Reinforced Composite. J Contemp Dent Pract 2004 May;(5)2:014-026.

scholarly journals Modular Paradigm for Composites: Modeling Hydrothermal Degradation of Glass Fibers

Fibers ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 83
Author(s):  
Andrey E. Krauklis
Keyword(s):  
Composite Materials ◽  
Glass Fibers ◽  
Hydrolytic Degradation ◽  
Short Review ◽  
Fiber Reinforced ◽  
Modeling Tools ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Degradation Rates ◽  
Structural Applications

Fiber-reinforced composite materials are often used in structural applications in humid, marine, and offshore environments. Superior mechanical properties are compromised by environmental ageing and hydrolytic degradation. Glass fibers are the most broadly used type of fiber reinforcement to date. However, they are also most severely affected by environmental degradation. The glass fiber degradation rates depend on: (1) glass formulation; (2) environmental factors: pH, T, stress; (3) sizing; (4) matrix polymer; (5) fiber orientation and composite layup. In this short review (communication), seven modules within the Modular Paradigm are reviewed and systematized. These modeling tools, encompassing both trivial and advanced formulas, enable the prediction of the environmental ageing of glass fibers, including the kinetics of mass loss, fiber radius reduction, environmental crack growth and loss of strength. The modeling toolbox is of use for both industry and academia, and the Modular Paradigm could become a valuable tool for such scenarios as lifetime prediction and the accelerated testing of fiber-reinforced composite materials.

FIBER-CONTINUOUS PILLAR-BOARD BIOCOMPOSITE STRUCTURE IN TUMBLEBUG ELYTRA

2010 ◽  
Vol 24 (01n02) ◽  
pp. 191-200
Author(s):  
B. CHEN ◽  
Q. YUAN ◽  
J. H. FAN ◽  
J. G. WANG ◽  
J. LUO
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Composite Structure ◽  
Rupture Strength ◽  
Glass Fibers ◽  
Experimental Result ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Scanning Electron

The observation of scanning electron microscope (SEM) showed that Tumblebug elytra consist of almost parallel upper and lower cuticles. Both of which are a kind of chitin-fiber-reinforced composite. There is a kind of chitin-fiber-reinforced composite pillars between the upper and lower cuticles, which support and connect the upper and lower cuticles uprightly. More careful observation showed that the chitin fibers in the pillars smoothly extend to the upper and lower composite cuticles forming a kind of fiber-continuous pillar-board composite (FCPBC) structure. Based on the observation, two kinds of pillar-board composite structure specimens, respective with continuous and discontinuous glass fibers, were fabricated with molding and felting processes. The rupture strengths of the two kinds of the specimens were tested and compared. It showed that the rupture strength of the specimens of the FCPBC structure is markedly larger than that of the specimens of the fiber-discontinuous pillar-board composite (FDPBC) structure. At last, the experimental result was analyzed for illumining the mechanism of the FCPBC structure in the enhancement of the strength.

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