title: Shear bond strength of a new self-adhering flowable composite resin for lithium disilicate-reinforced CAD/CAM ceramic material.
abstract: OBJECTIVE
  The purpose of this study was to evaluate and compare the effects of different surface pretreatment techniques on the surface roughness and shear bond strength of a new self-adhering flowable composite resin for use with lithium disilicate-reinforced CAD/CAM ceramic material.
  
  
  METHODS
  A total of one hundred thirty lithium disilicate CAD/CAM ceramic plates with dimensions of 6 mm × 4 mm and 3 mm thick were prepared. Specimens were then assigned into five groups (n=26) as follows: untreated control, coating with 30 µm silica oxide particles (Cojet™ Sand), 9.6% hydrofluoric acid etching, Er:YAG laser irradiation, and grinding with a high-speed fine diamond bur. A self-adhering flowable composite resin (Vertise Flow) was applied onto the pre-treated ceramic plates using the Ultradent shear bond Teflon mold system. Surface roughness was measured by atomic force microscopy. Shear bond strength test were performed using a universal testing machine at a crosshead speed of 1 mm/min. Surface roughness data were analyzed by one-way ANOVA and the Tukey HSD tests. Shear bond strength test values were analyzed by Kruskal-Wallis and Mann-Whitney U tests at α=.05.
  
  
  RESULTS
  Hydrofluoric acid etching and grinding with high-speed fine diamond bur produced significantly higher surface roughness than the other pretreatment groups (P<.05). Hydrofluoric acid etching and silica coating yielded the highest shear bond strength values (P<.001).
  
  
  CONCLUSIONS
  Self-adhering flowable composite resin used as repair composite resin exhibited very low bond strength irrespective of the surface pretreatments used.
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, Istanbul University, Capa-Istanbul, Turkey.
authors.forename: Ugur
authors.initials: U
authors.lastname: Erdemir
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, Istanbul University, Capa-Istanbul, Turkey.
authors.forename: Hande Sar
authors.initials: HS
authors.lastname: Sancakli
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Capa-Istanbul, Turkey.
authors.forename: Erkan
authors.initials: E
authors.lastname: Sancakli
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, Istanbul University, Capa-Istanbul, Turkey.
authors.forename: Meltem Mert
authors.initials: MM
authors.lastname: Eren
authors.affiliation: Faculty of Medicine Department of Biostatistics, Istanbul University, Capa-Istanbul, Turkey.
authors.forename: Sevda
authors.initials: S
authors.lastname: Ozel
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, Istanbul University, Capa-Istanbul, Turkey.
authors.forename: Taner
authors.initials: T
authors.lastname: Yucel
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, Istanbul University, Capa-Istanbul, Turkey.
authors.forename: Esra
authors.initials: E
authors.lastname: Yildiz
keywords: CAD/CAM ceramic; Er:YAG laser; Shear bond strength; Surface pretreatments; Tribochemical silica coating; Vertise flow