Posts Tagged ‘dental research’

Esstech to detail FIT 852 at IADR 2010 Barcelona

Wednesday, June 30th, 2010
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UDMA – TEGDMA Viable Resin System for Chlorhexidine Release

Thursday, June 17th, 2010
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Controlled Release of Chlorhexidine from UDMA-TEGDMA Resin

K.J. Anusavice, N.-Z. Zhang and C. Shen

J DENT RES 2006; 85; 950

ABSTRACT
Chlorhexidine salts are available in various formulations for dental applications. This study tested the hypothesis that the release of chlorhexidine from a urethane dimethacrylate and triethylene glycol dimethacrylate resin system can be effectively controlled by the chlorhexidine diacetate content and pH. The filler concentrations were 9.1, 23.1, or 33.3 wt%, and the filled resins were exposed to pH 4 and pH 6 acetate buffers. The results showed that Fickian diffusion was the dominant release mechanism. The rates of release were significantly higher in pH 4 buffer, which was attributed to the increase of chlorhexidine diacetate solubility at lower pH. The higher level of filler loading reduced the degree of polymerization, leading to a greater loss of organic components and higher chlorhexidine release rates.

Link:  http://jdr.sagepub.com/cgi/content/abstract/85/10/950


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BisGMA:TEGDMA:UDMA Composites Present Optimal Conversion and Mechanical Properties.

Friday, May 21st, 2010
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Bis-GMA  co-polymerizations: Influence on conversion, flexural properties, fracture toughness and susceptibility to ethanol degradation of experimental composites

Carmem S. Pfeifer, Laura R. Silva, Yoshio Kawano, Roberto R. Braga

Dental Materials Volume 25, Issue 9, Pages 1136-1141 (September 2009)

Objectives

The aim of this study was to evaluate the influence of monomer content on fracture toughness (KIc) before and after ethanol solution storage, flexural properties and degree of conversion (DC) of bisphenol A glycidyl methacrylate (Bis-GMA) co-polymers.

Methods

Five formulations were tested, containing Bis-GMA (B) combined with TEGDMA (T), UDMA (U) or Bis-EMA (E), as follows (in mol%): 30B:70T; 30B:35T:35U; 30B:70U; 30B:35T:35E; 30B:70E. Bimodal filler was introduced at 80wt%. Single-edge notched beams for fracture toughness (FT, 25mm×5mm×2.5mm, a/w=0.5, n=20) and 10mm×2mm×1mm beams for flexural strength (FS) and modulus (FM) determination (10mm×2mm×1mm, n=10) were built and then stored in distilled water for 24h at 37°C. All FS/FM beams and half of the FT specimens were immediately submitted to three-point bending test. The remaining FT specimens were stored in a 75%ethanol/25%water (v/v) solution for 3 months prior to testing. DC was determined with FT-Raman spectroscopy in fragments of both FT and FS/FM specimens at 24h. Data were submitted to one-way ANOVA/Tukey test (α=5%).

Results

The 30B:70T composite presented the highest KIc value (in MPam1/2) at 24h (1.3±0.4), statistically similar to 30B:35T:35U and 30B:70U, while 30B:70E presented the lowest value (0.5±0.1). After ethanol storage, reductions in KIc ranged from 33 to 72%. The 30B:70E material presented the lowest reduction in FT and 30B:70U, the highest. DC was similar among groups (69–73%), except for 30B:70U (52±4%, p<0.001). 30B:70U and 30B:35T:35U presented the highest FS (125±21 and 122±14MPa, respectively), statistically different from 30B:70T or 30B:70E (92±20 and 94±16MPa, respectively). Composites containing UDMA or Bis-EMA associated with Bis-GMA presented similar FM, statistically lower than 30B:35T:35U.

Significance

Composites formulated with Bis-GMA:TEGDMA:UDMA presented the best compromise between conversion and mechanical properties.

This version was accepted March 23, 2009.

Link, http://www.demajournal.com/article/S0109-5641%2809%2900162-6/abstract


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Dental Materials Blog

Tuesday, May 4th, 2010
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It’s our pleasure to present the Dental Materials Blog.

This blog presents topics of interest to dentists, material scientists and PhD students. Feel free to browse around and leave comments.  Recent Posts include:

Dental Materials Blog is coordinated by the Santini Miletic Research Group.  Providing research focused on Recent research has focused on dental resin based composites and adhesives using Raman Spectroscopy, High performance liquid chromatography, Scanning and Transmission Electron Microscopy and Atomic Force Microscopy.  You can contact the Santini Miletic Research Group at: info@santinimiletic.com

Santini Miletic Research

Santini Miletic Research


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Esstech to Present at IADR 2010

Wednesday, April 28th, 2010
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We are very excited to announce the details of our 2010 IADR presentation!

Physical Properties of New Low-Shrink Resin

Friday, July 16, 2010: 3 p.m. – 4:15 p.m.
Location: Exhibit Hall (CCIB)
A. JOHNSTON1, F. RUEGGEBERG2, H.R. RAWLS3, H. SLAFF1, T. BARCLIFT1, and J. DUFF1, 1Esstech Inc, Essington, PA, 2Medical College of Georgia, Augusta, GA, 3University of Texas Health Science Ctr at San Antonio, San Antonio, TX

2010 IADR Meeting Logo


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Optimizing Degree of Conversion, Strength, Young’s Modulus and Hardness of Bis-EMA, Bis-GMA and TEGDMA Formulations

Tuesday, April 20th, 2010
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Preparation and Evaluation of Dental Resin Luting Agents with Increasing Content of Bisphenol-A Ethoxylated Dimethacrylate

Rafael R. Moraes, Mário A.C. Sinhoreti, Lourenço Correr-Sobrinho, Fabrício A. Ogliari, Evandro Piva, and Cesar L. Petzhold

Journal of Biomaterials Applications, Jan 2010; vol. 24: pp. 453 – 473.

Abstract: Resin luting agents in which bisphenol-A glycidyl dimethacrylate (Bis-GMA) and/or triethylene glycol dimethacrylate (TEGDMA) are replaced with increasing amounts of bisphenol-A ethoxylated dimethacrylate are prepared. Degree of conversion (DC), diametral tensile strength (DTS), Young’s modulus (YM), Knoop hardness (KHN), film thickness (FT), water sorption (Wsp ), and solubility are evaluated. Regression analyses investigate the substitution of each monomer. The most appreciable differences are detected when TEGDMA is replaced: decreased DC, DTS, and Wsp, and increased YM, KHN, and FT. For substitution of Bis-GMA, the only significant differences are reduced Wsp and increased YM. An ideal formulation of resin cement would make use of the three monomers.

…Bis-GMA, TEGDMA, and/or Bis-EMA (Esstech Inc., Essington, PA, USA) were tested…photo-curable, 0.4 wt% of camphor- quinone (Esstech) and 0.8 wt% of N,N-dimethyl-p-toluidine…silanated strontium glass fillers (Esstech), 0.7 and 2 mm in size, to a constant…

This version was published on January 1, 2010.

Link:  http://jba.sagepub.com/cgi/content/abstract/24/5/453


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Esstech to Attend 2010 IADR Show

Friday, March 12th, 2010
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This year, we will be attending the IADR show in Barcelona, Spain.  We are excited to meet all of our international customers and researchers.  Look for us to present a poster on the mechanical properties of our low-shrink, FIT™ 852 Resin.  Let us know if you would like to schedule a meeting with us at the IADR.

 

2010 IADR Meeting Logo


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Esstech Attends 2010 AADR, Washington DC

Friday, March 12th, 2010
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Esstech representatives attended this year’s AADR show in Washington D.C.  It was wonderful seeing our customers face-to-face and learning about the ongoing research in the dental industry.  Many presenters referenced their use of Esstech materials in research – we are gratified by the continued interest from both industry and academia.  Keep up the good work!

 

2010 AADR  


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