title: Surface characterisation and bonding of Y-TZP following non-thermal plasma treatment.
abstract: OBJECTIVE
  (1) To chemically characterise Y-TZP surface via X-ray photoelectron spectroscopy (XPS) and evaluate the surface energy levels (SE) after non-thermal plasma (NTP). (2) To test the microtensile bond strength (MTBS) of Y-TZP bonded to cured composite disks, after a combination of different surface conditioning methods.
  
  
  METHODS
  Twenty-four Y-TZP discs (13.5mm×4mm) were obtained from the manufacturer and composite resin (Z-100) discs with similar dimensions were prepared. All discs were polished to 600 grit and divided into 8 groups (n=3 disks each), four control (non-NTP treated) and four experimental (NTP treated for 10s) groups. All groups received one of the four following treatments prior to cementation with Rely×Unicem cement: sand-blasting (SB), a Clearfil ceramic primer (MDP), sand-blasting+MDP (SBMDP), or baseline (B), no treatment. SE readings and surface roughness parameters were statistically analysed (ANOVA, Tukey's, p<0.05). Mixed model and paired samples t-tests were used to compare groups on MTBS.
  
  
  RESULTS
  XPS showed increase in O and decrease in C elements after NTP. The polar component increased for BP (42.20mN/m) and SBP (43.77mN/m). MTBS values for groups BP (21.3MPa), SBP (31MPa), MDPP (30.1MPa) and SBMDPP (32.3MPa) were significantly higher in specimens treated with NTP than their untreated counterparts B (9.1MPa), SB (14.4MPa), MDP (17.8MPa) and SBMDP (24.1MPa).
  
  
  CONCLUSIONS
  (1) Increase of O and decrease of C led to higher surface energy levels dictated by the polar component after NTP; (2) NTP application increased MTBS values of Y-TZP surfaces.
authors.affiliation: Piracicaba School of Dentistry-UNICAMP-Brazil, Department of Prosthodontics and Operative Dentistry, Tufts University, School of Dental Medicine, Boston, MA, USA. guigavalverde@yahoo.com
authors.forename: Guilherme B
authors.initials: GB
authors.lastname: Valverde
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Coelho
authors.forename: Malvin N
authors.initials: MN
authors.lastname: Janal
authors.forename: Fábio Cesar
authors.initials: FC
authors.lastname: Lorenzoni
authors.forename: Ricardo M
authors.initials: RM
authors.lastname: Carvalho
authors.forename: Van P
authors.initials: VP
authors.lastname: Thompson
authors.forename: Klaus-Dieter
authors.initials: KD
authors.lastname: Weltemann
authors.forename: Nelson R F A
authors.initials: NR
authors.lastname: Silva
mesh_terms: D000268:Adhesiveness; D000537:Aluminum Oxide / Q000737:chemistry; D001128:Argon / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D002484:Cementation / Q000379:methods; D002516:Ceramics / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing / Q000379:methods; D006801:Humans; D007368:Interferometry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D058626:Plasma Gases / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013500:Surface Tension; D013718:Tensile Strength; D017155:Wettability; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D017554:Carbon Compounds, Inorganic; D020099:Coated Materials, Biocompatible; D003188:Composite Resins; D003764:Dental Materials; D008689:Methacrylates; D058626:Plasma Gases; C483701:Rely X Unicem; D019279:Resin Cements; D017655:Silicon Compounds; C083568:Z100 composite resin; C499362:yttria stabilized tetragonal zirconia; D015019:Yttrium; D001128:Argon; D002244:Carbon; D012822:Silicon Dioxide; C069749:methacryloyloxydecyl dihydrogen phosphate; D015040:Zirconium; D000537:Aluminum Oxide; D010100:Oxygen; C022088:silicon carbide