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Thio-urethane oligomers improve the properties of light-cured resin cements.
- Source :
-
Dental materials : official publication of the Academy of Dental Materials [Dent Mater] 2015 May; Vol. 31 (5), pp. 565-74. Date of Electronic Publication: 2015 Mar 01. - Publication Year :
- 2015
-
Abstract
- Thio-urethanes were synthesized by combining 1,6-hexanediol-diissocyante (aliphatic) with pentaerythritol tetra-3-mercaptopropionate (PETMP) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (aromatic) with trimethylol-tris-3-mercaptopropionate (TMP), at 1:2 isocyanate:thiol, leaving pendant thiols. Oligomers were added at 10-30 phr to BisGMA-UDMA-TEGDMA (5:3:2, BUT). 25 wt% silanated inorganic fillers were added. Commercial cement (Relyx Veneer, 3M-ESPE) was also evaluated with 10-20 phr of aromatic oligomer. Near-IR was used to follow methacrylate conversion (DC) and rate of polymerization (Rpmax). Mechanical properties were evaluated in three-point bending (ISO 4049) for flexural strength/modulus (FS/FM, and toughness), and notched specimens (ASTM Standard E399-90) for fracture toughness (KIC). Polymerization stress (PS) was measured on the Bioman. Volumetric shrinkage (VS, %) was measured with the bonded disk technique. Results were analyzed with ANOVA/Tukey's test (α=5%). In general terms, for BUT cements, conversion and mechanical properties in flexure increased for selected groups with the addition of thio-urethane oligomers. The aromatic versions resulted in greater FS/FM than aliphatic. Fracture toughness increased by two-fold in the experimental groups (from 1.17 ± 0.36 MPam(1/2) to around 3.23 ± 0.22 MPam(1/2)). Rpmax decreased with the addition of thio-urethanes, though the vitrification point was not statistically different from the control. VS and PS decreased with both oligomers. For the commercial cement, 20 phr of oligomer increased DC, vitrification, reduced Rpmax and also significantly increased KIC, and reduced PS and FM. Thio-urethane oligomers were shown to favorably modify conventional dimethacrylate networks. Significant reductions in polymerization stress were achieved at the same time conversion and fracture toughness increased.<br /> (Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)
- Subjects :
- 3-Mercaptopropionic Acid analogs & derivatives
3-Mercaptopropionic Acid chemistry
Bisphenol A-Glycidyl Methacrylate chemistry
Elastic Modulus
Glycols chemistry
Isocyanates chemistry
Materials Testing
Methacrylates chemistry
Polyethylene Glycols chemistry
Polymerization
Polymethacrylic Acids chemistry
Polyurethanes chemistry
Propylene Glycols chemistry
Resin Cements chemical synthesis
Spectroscopy, Near-Infrared
Surface Properties
Tensile Strength
Light-Curing of Dental Adhesives
Resin Cements chemistry
Urethane chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1879-0097
- Volume :
- 31
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Dental materials : official publication of the Academy of Dental Materials
- Publication Type :
- Academic Journal
- Accession number :
- 25740124
- Full Text :
- https://doi.org/10.1016/j.dental.2015.02.008