title: Synthesis and evaluation of novel siloxane-methacrylate monomers used as dentin adhesives.
abstract: OBJECTIVE
  The objectives of this study were to synthesize two new siloxane-methacrylate (SM) monomers for application in dentin adhesives and to investigate the influence of different functionality of the siloxane-containing monomers on the adhesive photopolymerization, water sorption, and mechanical properties.
  
  
  METHODS
  Two siloxane-methacrylate monomers (SM1 and SM2) with four and eight methacrylate groups were synthesized. Dentin adhesives containing BisGMA, HEMA and the siloxane-methacrylate monomers were photo-polymerized. The experimental adhesives were compared with the control adhesive (HEMA/BisGMA, 45/55, w/w) and characterized with regard to degree of conversion (DC), water miscibility of the liquid resin, water sorption and dynamic mechanical analysis (DMA).
  
  
  RESULTS
  The experimental adhesives exhibited improved water miscibility as compared to the control. When cured in the presence of 12 wt% water to simulate the wet environment of the mouth, the SM-containing adhesives showed DC comparable to the control. The experimental adhesives showed higher rubbery modulus than the control under dry conditions. Under wet conditions, the mechanical properties of the formulations containing SM monomer with increased functionality were comparable with the control, even with more water sorption.
  
  
  CONCLUSIONS
  The concentration and functionality of the newly synthesized siloxane-methacrylate monomers affected the water miscibility, water sorption and mechanical properties of the adhesives. The experimental adhesives show improved water compatibility compared with the control. The mechanical properties were enhanced with an increase of the functionality of the siloxane-containing monomers. The results provide critical structure/property relationships and important information for future development of durable, versatile siloxane-containing dentin adhesives.
authors.affiliation: Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA.
authors.forename: Xueping
authors.initials: X
authors.lastname: Ge
authors.affiliation: Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA. Electronic address: yeq@ku.edu.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ye
authors.affiliation: Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA.
authors.forename: Linyong
authors.initials: L
authors.lastname: Song
authors.affiliation: Department of Civil Engineering, University of Kansas, Lawrence, KS, USA.
authors.forename: Anil
authors.initials: A
authors.lastname: Misra
authors.affiliation: Bioengineering Research Center, School of Engineering, University of Kansas, Lawrence, KS, USA; Department of Mechanical Engineering, University of Kansas, Lawrence, KS, USA. Electronic address: pspencer@ku.edu.
authors.forename: Paulette
authors.initials: P
authors.lastname: Spencer
mesh_terms: D000269:Adhesives; D003804:Dentin; D008689:Methacrylates / Q000737:chemistry*; D012833:Siloxanes / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D055114:X-Ray Microtomography
chemical_list: D000269:Adhesives; D008689:Methacrylates; D012833:Siloxanes; D014867:Water
keywords: Dentin adhesive; Dynamical mechanical property; Photopolymerization; Siloxane-methacrylate; Water miscibility