Posts Tagged ‘X-968-7044’

Optimal Solvent Ratio for Adhesive Systems

Wednesday, June 1st, 2011
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Hybridization morphology and dentin bond stability of self-etch primers with different ethanol/water ratios

Silvia T. Fontes, Giana S. Lima, Fabrício A. Ogliari, Evandro Piva and Rafael R. Moraes

Odontology, DOI: 10.1007/s10266-011-0030-5

Abstract


This study evaluated the influence of ethanol/water ratios on the bond strength to dentin of experimental two-step, self-etch adhesive systems. Self-etch primers were prepared with constant 40 mass % of solvents. The ethanol/water ratios tested were 7:1 (P1), 3:1 (P2), and 1:1 (P3); primers with only ethanol (PE) or water (PW) as solvent were also tested. The bond strength to the dentin was investigated through a microtensile bond strength test. Resin–dentin beam-shaped specimens were obtained and tested after 24 h, 6 months, and 1 year of storage in water at 37°C. The hybridization morphology was analyzed using SEM. For bond strength at 24 h, PE = P1, P1 = P2, and P2, P3 and PW > PE. After 6 months, PE = P1 < P2, P3 and PW. After 1 year, no significant differences among the materials were detected. No significant differences among the periods were detected for PE. For P1, 24 h > 6 months = 1 year. For P2, P3 and PW, 24 h = 6 months > 1 year. For PE and P1, adhesive failures were predominant at 24 h, mixed or adhesive failures after 6 months, and premature debonding was predominant after 1 year. For P2, mixed failures were predominant at 24 h and 6 months, and premature debonding after 1 year. For P3 and PW, mixed failures were predominant at all storage periods. The SEM analysis revealed no clear differences in the hybridization patterns yielded by the water-based primers; PE showed formation of irregular resin tags.
Odontology 123 Page 6. Acknowledgments This study was partially supported by grant #04/ 1374.1 from the FAPERGS, Brazil. The authors also thank Esstech, Inc. for donating the reagents used in the present investigation


LINK:  http://www.springerlink.com/content/84hl1518hl85023w/

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Esstech’s TEGDMA Incorporated in Hydrogel Synthesis Patent

Tuesday, February 22nd, 2011
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Forming Clear, wettable silicone hydrogel articles without surface treatments

Document Type and Number: Kind Code:  A1
Inventors: Vanderlaan, Douglas C. (Jacksonville, FL, US), Petisce, James R. (San Diego, CA, US), Alli, Azaam (Jacksonville, FL, US), Mccabe, Kevin P. (St. Augustine Beach, FL, US)
ABSTRACT

The present invention is a composition, which may be used to form contact lenses, comprising at least one silicone containing component, at least one hydrophilic component, at least one high molecular weight hydrophilic polymer and at least one diluent with an alpha value of about 0.5 to about 1 and a Hansen solubility parameter of less than about 10.
…Some of the diluents from Example 1 were used to make contact lenses from the monomer mix shown in Table 3…
TABLE 3
Component level (wt)
DMA 31%
PVP (K90) 6%
mPDMS 1000 45%
HEMA 14.75 %
CGI-819 0.25%
TEGDMA 1.5%
Norbloc< /td> 1.5%
monomer/diluent ratio 60/40
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HEMA Incorporated in Tissue Engineering Scaffolds

Monday, January 24th, 2011
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Modification of polymer networks with bone sialoprotein promotes cell attachment and spreading

Wailen D. Chan, Harvey A. Goldberg, Graeme K. Hunter, S. J. Dixon,  Amin S. Rizkalla, Journal of Biomedical Materials Research Part A

ABSTRACT:

Biomaterials used for tissue engineering scaffolds act as temporary substrates, on which cells deposit newly synthesized extracellular matrix. In cartilage tissue engineering, polycaprolactone/poly(2-hydroxyethyl methacrylate) (PCL/pHEMA) polymer blends have been used as scaffold materials, but their use in osseous tissue engineering has been more limited. The objective of this study was to evaluate modification of PCL/pHEMA surfaces with bone sialoprotein (BSP), an extracellular matrix protein important in regulating osseous tissue formation. Modification of surfaces with BSP significantly enhanced osteoblastic cell attachment and spreading, without compromising proliferation. Thus, BSP-immobilization may be a useful strategy for optimizing scaffolds for skeletal tissue engineering.

INTRODUCTION:

Tissue regeneration requires a substrate that allows cells to adhere, proliferate, and eventually form their own matrix. Polymers from the polyester family, such as poly(lactic acid), poly(glycolic acid), or their copolymers, have been the most commonly used materials to fabricate scaffolds for skeletal tissue engineering applications.  More recently, another member of this family, poly(ε-caprolactone) (PCL) has also been considered for skeletal tissue engineering. Human primary osteoblasts demonstrate attachment and spreading on PCL surfaces.

Poly(2-hydroxyethyl methacrylate) (pHEMA) is another polymer that has been used extensively as a biomaterial in drug delivery and soft-tissue applications. pHEMA gels have a propensity to calcify after prolonged implantation periods, leading to the suggestion that pHEMA could be used for filling bone or dental defects…

PREPARATION:

PCL/pHEMA semi-interpenetrating networks (sIPN’s) were prepared by combining HEMA monomer (Esstech, Essington, PA), a low-molecular-weight PCL (CAPA 2302, 3000 g/mol; Solvay Interox, Warrington, UK), and a high-molecular-weight PCL (CAPA 6506, 50,000 g/mol; Solvay Interox) in a 5.5:2.5:1 weight ratio, respectively. PCL and HEMA monomer were mixed together and placed in an oven at 60oC to facilitate melting and dissolution of PCL in HEMA monomer. After melting, the compositions were thoroughly mixed to ensure a homogenous distribution. Camphorquinone (Esstech) was added to the mixtures at 0.2% by weight of HEMA monomer. The mixtures were sonicated for approximately 8 min to evenly dissolve the camphorquinone. 1 mL polypropylene syringes (∼4 mm internal diameter) were subsequently filled with PCL/HEMA monomer compositions and cured using a Triad 2000 light-curing system (Dentsply, York, PA).


Article first published online: 31 MAR 2010, DOI:  10.1002/jbm.a.32715, Copyright 2010 Wiley Periodicals, Inc.

Volume 94A, Issue 3, pages 945–952, 1 September 2010

Link:  http://onlinelibrary.wiley.com/doi/10.1002/jbm.a.32715/abstract


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X-726-0000 Serves as HEMA Alternative and Improves Degree of Conversion

Wednesday, March 31st, 2010
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Polymerization Shrinkage and Stress Development in Amorphous Calcium Phosphate/Urethane Dimethacrylate Polymeric Composites

J.M. Antonucci, W.F. Regnault, and D. Skrtic

Journal of Composite Materials, Feb 2010; vol. 44: pp. 355 – 367. DOI: 10.1177/0021998309345180

Abstract: This study explores how substituting a new high molecular mass oligomeric poly(ethylene glycol) extended urethane dimethacrylate (UDMA) (PEG-U) for 2-hydroxyethyl methacrylate (HEMA) in photo-activated UDMA resins affects degree of vinyl conversion (DC), polymerization shrinkage (PS), stress development (PSSD) and biaxial flexure strength (BFS) of their amorphous calcium phosphate (ACP) composites. The composites were prepared from four types of resins (UDMA, PEG-U, UDMA/HEMA, and UDMA/PEG-U) and zirconia-hybridized ACP. Introducing PEG-U improved DC, while not adversely affecting PS, PSSD, and the BFS of composites. This improvement in DC is attributed to the long, more flexible structure between the vinyl groups of PEG-U and its higher molecular mass compared to poly(HEMA). The results imply that PEG-U has the potential to serve as an alternative to HEMA in dental and other biomedical applications.

…material research program supported by FDA, NIST, and ADAF. Generous contribution of UDMA, PEG- U, and HEMA monomers from Esstech, Essington, PA, USA, is gratefully acknowledged. Polymerization Shrinkage and Stress in ACP Composites 365 The authors also…

This version was published on February 1, 2010

Link: http://jcm.sagepub.com/cgi/content/abstract/44/3/355


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