title: Compositional design and optimization of dentin adhesive with neutralization capability.
abstract: OBJECTIVE
  The objective of this work was to investigate the polymerization behavior, neutralization capability, and mechanical properties of dentin adhesive formulations with the addition of the tertiary amine co-monomer, 2-N-morpholinoethyl methacrylate (MEMA).
  
  
  METHODS
  A co-monomer mixture based on HEMA/BisGMA (45/55, w/w) was used as a control adhesive. Compared with the control formulation, the MEMA-containing adhesive formulations were characterized comprehensively with regard to water miscibility of liquid resin, water sorption and solubility of cured polymer, real-time photopolymerization kinetics, dynamic mechanical analysis (DMA), and modulated differential scanning calorimetry (MDSC). The neutralization capacity was characterized by monitoring the pH shift of 1mM lactic acid (LA) solution, in which the adhesive polymers were soaked.
  
  
  RESULTS
  With increasing MEMA concentrations, experimental copolymers showed higher water sorption, lower glass transition temperature and lower crosslinking density compared to the control. The pH values of LA solution gradually increased from 3.5 to about 6.0-6.5 after 90 days. With the increase in crosslinking density of the copolymers, the neutralization rate was depressed. The optimal MEMA concentration was between 20 and 40 wt%.
  
  
  CONCLUSIONS
  As compared to the control, the results indicated that the MEMA-functionalized copolymer showed neutralization capability. The crosslinking density of the copolymer networks influenced the neutralization rate.
authors.affiliation: University of Kansas, Bioengineering Research Center, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA.
authors.forename: Linyong
authors.initials: L
authors.lastname: Song
authors.affiliation: University of Kansas, Bioengineering Research Center, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA. Electronic address: yeq@ku.edu.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ye
authors.affiliation: University of Kansas, Bioengineering Research Center, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA.
authors.forename: Xueping
authors.initials: X
authors.lastname: Ge
authors.affiliation: University of Kansas, Bioengineering Research Center, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA; University of Kansas, Department of Mechanical Engineering, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA. Electronic address: pspencer@ku.edu.
authors.forename: Paulette
authors.initials: P
authors.lastname: Spencer
mesh_terms: D002152:Calorimetry, Differential Scanning; D055117:Curing Lights, Dental; D003738:Dental Cements / Q000737:chemistry* / Q000528:radiation effects; D005898:Glass / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000737:chemistry; D008027:Light; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry* / Q000528:radiation effects; D009025:Morpholines / Q000737:chemistry* / Q000528:radiation effects; D055668:Photochemical Processes; D058105:Polymerization; D012995:Solubility; D012996:Solutions; D013997:Time Factors; D044366:Transition Temperature; D014867:Water / Q000737:chemistry
chemical_list: C000613589:2-N-morpholinoethyl methacrylate; D003738:Dental Cements; D008689:Methacrylates; D009025:Morpholines; D012996:Solutions; D014867:Water; D019344:Lactic Acid
keywords: Crosslinking density; Dentin adhesive; Neutralization capacity; Photopolymerization; Tertiary amine