Posts Tagged ‘Adhesive Monomer’

4-META History and Applications

Tuesday, October 19th, 2010
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4-META use in dentistry:  A literature review

Jeffrey Chai Chang, DDS, MS, Thomas L. Hurst, DDS, MS, Deborah A. Hart, DMD, and Allan W. Estey, DDSd.  University of Texas Dental Branch, and V.A. Medical Center, Houston, Texas

(J Prosthet Dent 2002;87:216-24.)

ABSTRACT:
4-META (4-methacryloyloxyethy trimellitate anhydride) adhesive resins have been reported in the dental literature for more than 20 years. While the majority of available bonding agents available have gone through changes from the first generation to the fifth, 4-META products have had basically the same ingredients since inception. They consistently produce excellent results, are easy to use, and are not technique-sensitive. Some new adhesive products may have higher bond strengths, but the optimum strength for adhesive materials has not been determined clinically.  For ease of use and consistency of results, 4-META adhesive resins appear to be a good choice.

LINK: http://www.prosdent.org/article/S0022-3913%2802%2961035-2/abstract


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PMGDM / UDMA Used in Remineralization Applications

Friday, September 10th, 2010
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Effects of adhesive, base and diluent monomers on water sorption and conversion of experimental resins

Sabine H. Dickens, Glenn M. Flaim, Cynthia J.E. Floyd

Dental Materials Volume 26, Issue 7, Pages 675-681 (July 2010)

Objectives: To establish the relationship of resin composition and resin hydrophilicity (indicated by solubility parameters and logP) to water sorption (WS), solubility, and degree of double bond conversion (DC) of resin mixtures designed for adhesive restoratives by varying the concentration of pyromellitic glycerol dimethacrylate (PMGDM) and various co-monomers.

Methods: Sixteen resin mixtures were prepared with (30–70) mass fraction % PMGDM. At given PMGDM concentrations there were up to five compositions with increasing logP. Polymer disks (13mm×0.7mm) were exposed to 96% relative humidity (RH) to determine water sorption in humid atmosphere (WSH) and subsequently immersed in water for immersion water sorption (WSI) and solubility. DC was assessed by near infrared spectroscopy.

Results: WSI was somewhat higher than WSH, which ranged from (2.1 to 5.3) mass fraction %. Both data were positively correlated to PMGDM concentrations [Pearson correlation, p<0.02; R2=0.74, 0.73 (WSI)] and solubility (R2=0.64), but not to logP. When grouped by structural similarities, i.e., base resins with bisphenol A core (Group B), Group O containing diluent monomers, or Group U containing urethane dimethacrylate, WS within each group was inversely correlated to logP with R2=0.98, 0.81, 0.95, and WS/solubility correlation improved with R2=0.88, 0.92 and 0.75, respectively. Solubility ranging from 0.3% to 2.3% was inversely related to DC (r=−0.872). Conversion ranging from 41% to 81% was lower for resins with high base monomer concentrations and highest in mixtures with UDMA.

Significance: LogP was a good predictor of WS after grouping the resins according to functional, compositional and structural similarities. WS and conversion were reasonably well predicted from Hoy’s solubility parameters and other physical resin properties.

Link:  http://www.demajournal.com/article/S0109-5641%2810%2900066-7/abstract


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