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Dent Mater. 2018 Oct;34(10):1459-1465. doi: 10.1016/ Epub 2018 Aug 1.

Development of an oxirane/acrylate interpenetrating polymer network (IPN) resin system.

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Department of Comprehensive Dentistry, the University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.
Department of Periodontics, JBSA-Randolph, San Antonio, TX 78150, United States.
DM Healthcare Products, Inc., San Diego, CA, United States.
Department of Comprehensive Dentistry, the University of Texas Health Science Center at San Antonio, San Antonio, TX, United States. Electronic address:



Develop a hydrophobic, degradation-resistant dental restorative based on an Oxirane-Acrylate IPN System (OASys) with low shrinkage-stress to substantially extend clinical lifetime.


Unfilled OASys blends were prepared using dipenta-erythritol-hexaacrylate (DPHA) and p-cycloaliphatic-diepoxide (EP5000). Varying proportions of camphorquinone/iodonium photoinitiator, with a co-reactant oligomeric-diol, served as the experimental curing system. The effects of oxirane-acrylate ratio on the degree-of-cure (Durometer-D hardness), hydrophobicity (contact angle), mechanical properties (3-point bending), near-infrared FTIR degree-of-conversion (DoC), polymerization shrinkage, and shrinkage stress were determined. 70:30 BisGMA:TEGDMA resin served as control.


Oxirane tended to decrease hardness and increase hydrophobicity. 0:100, 25:75, 50:50 EP5000:DPHA are harder after 24h than control. 75:25 and 100:0 EP5000:DPHA increased in hardness over 24h, but were softer than control. All groups increased in contact angle over 24h. After 24h, 50:50, 75:25 and 0:100 EP5000:DPHA were more hydrophobic (∼75-84°) than the control (∼65°). Acrylate DoC was ∼60% across all experimental groups. Initial oxirane conversion varied from ∼42% in 100:0 EP5000:DPHA to ∼82% 75:25 EP5000:DPHA. However, oxirane DoC increased for 100:0 EP5000:DPHA to ∼73° over 24h, demonstrating dark cure. Moduli and ultimate transverse strengths of OASys groups were higher than for 0:100 EP5000:DPHA, with 50:50 EP5000:DPHA having higher modulus than other experimental groups. However, the control had higher modulus and UTS than all experimental groups. Volumetric shrinkage averaged 7% for experimental groups, but stress decreased dramatically with increasing oxirane content.


Hydrophobic, low shrinkage-stress OASys resins are promising for development of composites that improve longevity and reduce the cost of dental care.


Acrylate; Cationic photoinitiation; Degree of conversion; Hydrophobicity; Interpenetrating network; Oxirane; Restorative resin; Shrinkage stress; Volumetric shrinkage

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