title: Relation of enamel prism orientation to microtensile bond strength.
abstract: OBJECTIVE
  To evaluate the effect of enamel prism orientation on microtensile bond strengths (MTBS) to enamel using two current bonding systems.
  
  
  METHODS
  The crown segments of extracted human third molars were cut mesio-distally to obtain buccal and lingual halves. One of the halves was cut horizontally at the middle of the crown to make a flat enamel surface parallel to prism orientation (parallel specimen). The other half was ground at the equator of the crown to produce a flat enamel surface perpendicular to the prism orientation (perpendicular specimen). Each surface was ground with 600 grit silicone carbide paper, treated with Clearfil Liner Bond IIsigma (LB) or Single Bond (SB) according to the manufacturers' instructions and resin composite, AP-X or Z100, respectively, was built up onto it. After storage in water at 37 degrees C for 24 hours, all bonded specimens were sectioned and trimmed for measuring MTBS. In MTBS, the parallel specimens were stressed perpendicular to the prism long axis and the perpendicular specimens were stressed parallel to the prism axis.
  
  
  RESULTS
  MTBS of specimens stressed perpendicular to the prism long axis were 11.93 +/- 5.56 MPa for LB and 10.97 +/- 1.80 MPa for SB. MTBS of specimens stressed parallel to the prism axis in LB and SB were 19.07 +/- 6.35 MPa and 23.99 +/- 9.20 MPa, respectively. For each prism orientation, no difference in MTBS was found between the bonding systems (P> 0.05). Both systems showed lower MTBS in specimens stressed perpendicular to the prism long axis than in specimens stressed parallel to the prism axis.
authors.affiliation: Department of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan. iketaka@den.hokudai.ac.jp
authors.forename: Takatsumi
authors.initials: T
authors.lastname: Ikeda
authors.forename: Shigeru
authors.initials: S
authors.lastname: Uno
authors.forename: Toru
authors.initials: T
authors.lastname: Tanaka
authors.forename: Susumu
authors.initials: S
authors.lastname: Kawakami
authors.forename: Hisanori
authors.initials: H
authors.lastname: Komatsu
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Sano
mesh_terms: D000134:Acid Etching, Dental; D000268:Adhesiveness; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure*; D003799:Dental Stress Analysis / Q000295:instrumentation; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D012822:Silicon Dioxide; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry; D015040:Zirconium
chemical_list: D017554:Carbon Compounds, Inorganic; C112828:Clearfil AP-X; C112274:Clearfil Liner Bond 2; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; D017655:Silicon Compounds; C083568:Z100 composite resin; C115612:single bond; D014867:Water; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D015040:Zirconium; C022088:silicon carbide