title: Effects of diamond bur particle size on dentin bond strength.
abstract: OBJECTIVE
  To evaluate the influence of particle size of originally designed diamond burs on resin adhesion to sound young human permanent dentin.
  
  
  METHODS
  The buccal surfaces of 105 premolars were used. Six test groups were prepared. The adhesive systems and resin-based composites used for Groups 1-3 were Clearfil SE Bond (SE) and Clearfil AP-X, and for Groups 4-6, Single Bond (SB) and Z250. Flat dentin surfaces were finely ground with 25 microm particle size IW-G5 diamond bur (IW-G5, Groups 1 and 4), 50 microm particle size IW-G4 diamond bur (IW-G4, Groups 2 and 5), or 600-grit SiC paper (#600, Groups 3 and 6). The microstructure of the prepared dentin, SE primed or SB etched dentin, and resin-dentin interfaces of each group (3 teeth/group) were studied using SEM. Shear bond strengths (SBS) in MPa were tested (10 teeth/group), and the failed surfaces were observed using SEM. Data was statistically analyzed using ANOVA and Fisher's PLSD at P < 0.05.
  
  
  RESULTS
  The dentin ground with the IW-G5 or IW-G4 bur was rougher than the dentin ground with the 600-grit SiC paper. The mean SBS (MPa) for Groups 1-6 were: 32.3 +/- 5.0, 27.6 +/- 6.4, 21.3 +/- 3.6, 5.9 +/- 2.9, 6.5 +/- 3.1 and 5.3 +/- 2.0. The SBS of Groups 1-3 (SE groups) were significantly higher than those of Groups 4-6 (SB groups). The SBS of Group 1 (IW-G5, SE group) was significantly higher than those of Groups 2 (IW-G4, SE group) and 3 (#600, SE group), and the SBS of Group 2 was significantly higher than that of Group 3. There was no significant difference for SBS among Groups 4, 5 and 6. Fracture mode after SBS test mainly showed mixed fracture (adhesive and cohesive resin fracture) for the SE groups, and adhesive fracture for the SB groups.
authors.affiliation: Nagasaki University Graduate School of Biomedical Sciences, Department of Developmental and Reconstructive Medicine, Division of Pediatric Dentistry, 1-7-1, Sakamoto, Nagasaki 852-8588, Japan. hosoya@net.nagasaki-u.ac.jp
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Hosoya
authors.forename: Hiroe
authors.initials: H
authors.lastname: Shinkawa
authors.forename: Chikako
authors.initials: C
authors.lastname: Suefiji
authors.forename: Kumiko
authors.initials: K
authors.lastname: Nozaka
authors.forename: Franklin
authors.initials: F
authors.lastname: García-Godoy
mesh_terms: D000704:Analysis of Variance; D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000295:instrumentation*; D003762:Dental Instruments; D003799:Dental Stress Analysis; D003804:Dentin; D017220:Dentin-Bonding Agents; D018130:Diamond; D006801:Humans; D008689:Methacrylates; D010316:Particle Size; D019279:Resin Cements; D033081:Shear Strength; D016369:Smear Layer; D013499:Surface Properties
chemical_list: C112828:Clearfil AP-X; C438313:Clearfil SE Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; D008689:Methacrylates; D019279:Resin Cements; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; D018130:Diamond