Methacryloyl derivitized hyperbranched polyester. 2. Photo-polymerization and properties for dental resin systems

The purpose of this research is to demonstrate the usefulness of the synthe sized hyperbranched multi-methacrylates (H-MMAs) in dental applications. We synthesized three hyperbranched multi-methacrylate oligomers and evaluated them as modifiers for use in the dental resin system: bisphenol A glycidyl dimethacrylate (BisGMA)/tri(ethylene glycol) dimethacrylate (TEGDMA). Thei r photo-polymerization activities, viscosity, mechanical properties, such a s compression, diametral tensile, and flexural strength, were evaluated. H- MMAs (10%) modified dental resins have lower polymerization shrinkage and a bout 15% increase in mechanical strength compared to the Bis-BisGMA control . For example, H30-MMA has compressive, diametral tensile, and flexural str ength of 576, 47, and 85 MPa, compared with the BisGMA control having 497, 43, and 77 MPa. In addition, hyperbranched polymer modified resins have hig her glass transition temperature (T-g) and lower thermal expansion coeffici ent (alpha) than the control. This research is significant both for increas ing our knowledge about hyperbranched multi-functional polymers as well as leading to new dental resin systems with better performance.