title: Non-thermal atmospheric plasma brush induces HEMA grafting onto dentin collagen.
abstract: OBJECTIVE
  Non-thermal atmospheric plasma (NTAP) brush has been regarded as a promising technique to enhance dental interfacial bonding. However, the principal enhancement mechanisms have not been well identified. In this study, the effect of non-thermal plasmas on grafting of HEMA, a typical dental monomer, onto dentin collagen thin films was investigated.
  
  
  METHODS
  Human dentin was sectioned into 10-μm-thick films. After total demineralization in 0.5M EDTA solution for 30min, the dentin collagen films were water-rinsed, air-dried, treated with 35wt% HEMA aqueous solution. The films were then subject to plasma-exposure under a NTAP brush with different time (1-8min)/input power (5-15W). For comparison, the dentin collagen films were also treated with the above HEMA solution containing photo-initiators, then subject to light-curing. After plasma-exposure or light-curing, the HEMA-collagen films were rinsed in deionized water, and then examined by FTIR spectroscopy and TEM.
  
  
  RESULTS
  The FITR results indicated that plasma-exposure could induce significant HEMA grafting onto dentin collagen thin films. In contrast, light-curing led to no detectable interaction of HEMA with dentin collagen. Quantitative IR spectral analysis (i.e., 1720/3075 or 749/3075, HEMA/collagen ratios) further suggested that the grafting efficacy of HEMA onto the plasma-exposed collagen thin films strongly depended on the treatment time and input power of plasmas. TEM results indicated that plasma treatment did not alter collagen's banding structure.
  
  
  CONCLUSIONS
  The current study provides deeper insight into the mechanism of dental adhesion enhancement induced by non-thermal plasmas treatment. The NTAP brush could be a promising method to create chemical bond between resin monomers and dentin collagen.
authors.affiliation: Department of Prosthodontics, Affiliated Hospital of Stomatology, Chongqing Medical University, Chongqing 401147, China; Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA.
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Chen
authors.affiliation: Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Dusevich
authors.affiliation: Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Center for Surface Science and Plasma Technology, Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Qingsong
authors.initials: Q
authors.lastname: Yu
authors.affiliation: Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA. Electronic address: wangyo@umkc.edu.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
mesh_terms: D001713:Biphenyl Compounds / Q000737:chemistry; D002164:Camphor / Q000031:analogs & derivatives / Q000737:chemistry; D003094:Collagen / Q000737:chemistry*; D003648:Decalcification Technique; D001840:Dental Bonding / Q000379:methods*; D003804:Dentin / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000379:methods; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D009861:Onium Compounds / Q000737:chemistry; D058567:Photoinitiators, Dental / Q000737:chemistry; D058626:Plasma Gases / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013997:Time Factors; D062366:para-Aminobenzoates / Q000737:chemistry
chemical_list: D001713:Biphenyl Compounds; D008689:Methacrylates; D009861:Onium Compounds; D058567:Photoinitiators, Dental; D058626:Plasma Gases; C523330:ethyl 4-N,N-dimethylaminobenzoate; D062366:para-Aminobenzoates; C031291:diphenyliodonium; C005044:hydroxyethyl methacrylate; D002164:Camphor; D003094:Collagen; D004492:Edetic Acid; C553149:camphorquinone
keywords: Dental monomer; Dentin collagen; FTIR; Grafting; Non-thermal plasmas; TEM