title: Influence of Conditioning Time of Universal Adhesives on Adhesive Properties and Enamel-Etching Pattern.
abstract: OBJECTIVE
  To evaluate the effect of application protocol in resin-enamel microshear bond strength (μSBS), in situ degree of conversion, and etching pattern of three universal adhesive systems.
  
  
  METHODS
  Sixty-three extracted third molars were sectioned in four parts (buccal, lingual, and proximals) and divided into nine groups, according to the combination of the main factors-Adhesive (Clearfil Universal, Kuraray Noritake Dental Inc, Tokyo, Japan; Futurabond U, VOCO, Cuxhaven, Germany; and Scotchbond Universal Adhesive, 3M ESPE, St Paul, MN, USA)-and enamel treatment/application time (etch-and-rinse mode [ER], self-etch [SE] application for 20 seconds [SE20], and SE application for 40 seconds [SE40]). Specimens were stored in water (37°C/24 h) and tested at 1.0 mm/min (μSBS). The degree of conversion of the adhesives at the resin-enamel interfaces was evaluated using micro-Raman spectroscopy. The enamel-etching pattern was evaluated under a scanning electron microscope. Data were analyzed with two-way analysis of variance and Tukey test (α=0.05).
  
  
  RESULTS
  In general, the application of the universal adhesives in the SE40 produced μSBS and degree of conversion that were higher than in the SE20 (p<0.01) and similar to the ER mode. The deepest enamel-etching pattern was obtained in the ER mode, followed by the SE40.
  
  
  CONCLUSIONS
  The active and prolonged application of universal adhesives in the SE mode may be a viable alternative to increase the degree of conversion, etching pattern, and resin-enamel bond strength.
authors.forename: A M
authors.initials: AM
authors.lastname: Cardenas
authors.forename: F
authors.initials: F
authors.lastname: Siqueira
authors.forename: J
authors.initials: J
authors.lastname: Rocha
authors.forename: A L
authors.initials: AL
authors.lastname: Szesz
authors.forename: M
authors.initials: M
authors.lastname: Anwar
authors.forename: F
authors.initials: F
authors.lastname: El-Askary
authors.forename: A
authors.initials: A
authors.lastname: Reis
authors.forename: A
authors.initials: A
authors.lastname: Loguercio