title: Effect of a non-thermal, atmospheric-pressure, plasma brush on conversion of model self-etch adhesive formulations compared to conventional photo-polymerization.
abstract: OBJECTIVE
  To determine the effectiveness and efficiency of non-thermal, atmospheric plasmas for inducing polymerization of model dental self-etch adhesives.
  
  
  METHODS
  The monomer mixtures used were bis-[2-(methacryloyloxy)ethyl] phosphate (2MP) and 2-hydroxyethyl methacrylate (HEMA), with mass ratios of 70/30, 50/50 and 30/70. Water was added to the above formulations: 10-30wt%. These monomer/water mixtures were treated steadily for 40s under a non-thermal atmospheric plasma brush working at temperatures from 32 to 35°C. For comparison, photo-initiators were added to the above formulations for photo-polymerization studies, which were light-cured for 40s. The degree of conversion (DC) of both the plasma- and light-cured samples was measured using FTIR spectroscopy with an attenuated total reflectance attachment.
  
  
  RESULTS
  The non-thermal plasma brush was effective in inducing polymerization of the model self-etch adhesives. The presence of water did not negatively affect the DC of plasma-cured samples. Indeed, DC values slightly increased, with increasing water content in adhesives: from 58.3% to 68.7% when the water content increased from 10% to 30% in the adhesives with a 50/50 (2MP/HEMA) mass ratio. Conversion values of the plasma-cured groups were higher than those of light-cured samples with the same mass ratio and water content. Spectral differences between the plasma- and light-cured groups indicate subtle structural distinctions in the resultant polymer networks.
  
  
  CONCLUSIONS
  This research if the first to demonstrate that the non-thermal plasma brush induces polymerization of model adhesives under clinical settings by direct/indirect energy transfer. This device shows promise for polymerization of dental composite restorations having enhanced properties and performance.
authors.affiliation: Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA.
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Chen
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Yao
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.forename: Qingsong
authors.initials: Q
authors.lastname: Yu
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
mesh_terms: D001128:Argon / Q000737:chemistry; D001274:Atmospheric Pressure; D002164:Camphor / Q000031:analogs & derivatives / Q000737:chemistry / Q000528:radiation effects; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D017666:Deuterium Oxide / Q000737:chemistry; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000145:classification; D008689:Methacrylates / Q000737:chemistry / Q000528:radiation effects; D058567:Photoinitiators, Dental / Q000737:chemistry / Q000528:radiation effects; D058626:Plasma Gases / Q000737:chemistry*; D058105:Polymerization; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry; D062366:para-Aminobenzoates / Q000737:chemistry / Q000528:radiation effects
chemical_list: C454021:2-(methacryloyloxy)ethyl phosphate; D003188:Composite Resins; D003764:Dental Materials; D008689:Methacrylates; D058567:Photoinitiators, Dental; D058626:Plasma Gases; C523330:ethyl 4-N,N-dimethylaminobenzoate; D062366:para-Aminobenzoates; D014867:Water; D001128:Argon; C005044:hydroxyethyl methacrylate; D002164:Camphor; D017666:Deuterium Oxide; C553149:camphorquinone