title: Effect of surface treatments on the spreading velocity of simplified adhesive systems.
abstract: OBJECTIVE
  To determine the roughness of glass surfaces submitted to different treatments and to correlate it with the spreading velocity of two adhesive systems.
  
  
  METHODS
  Glass slides were used as substrates to evaluate the spreading velocity of Single Bond and Prime & Bond NT adhesive systems. Six different surface treatments were compared: 1) no treatment; 2) silanization (SL); 3) sandblasting (SB); 4) SB + SL; 5) 10% hydrofluoric acid treatment (HF); 6) HF + SL. Before and after treatments, surface roughness was measured by a profilometer (Ra, microm). Drop volumes (10 microl) of the adhesive systems were deposited onto substrates with a micropipette to observe materials spreading during 30s. Data were expressed in mm/s as spreading velocity. Statistical significances among groups were analyzed using one-way and two-way-ANOVA designs and the SNK test.
  
  
  RESULTS
  Significant differences in spreading velocity were found between materials (p < 0.001) and among treatments (p < 0.001). Silanization decreased the spreading velocity for both adhesives in comparison to groups where it was not performed (p < 0.05). Differences in roughness were found only for SB surfaces that were rougher than the others (p < 0.05). Silanization decreased the roughness of SB surfaces (p < 0.05). Linear regression did not indicate any correlation between spreading velocity and roughness (R = 0.173).
  
  
  CONCLUSIONS
  Although surface treatments yielded different roughness, they did not provide differences in the spreading velocity of the simplified bonding systems studied. Silanization decreased bonding systems' spreading velocities.
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Flávia B
authors.initials: FB
authors.lastname: Pazinatto
authors.forename: Fernanda A
authors.initials: FA
authors.lastname: Lopes
authors.forename: Luiz
authors.initials: L
authors.lastname: Marquezini Junior
authors.forename: Fabrício L A
authors.initials: FL
authors.lastname: de Castro
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Atta