title: Microtensile bond strength and micromorphologic analysis of surface-treated resin nanoceramics.
abstract: OBJECTIVE
  The aim of this study was to evaluate the influence of different surface treatment methods on the microtensile bond strength of resin cement to resin nanoceramic (RNC).
  
  
  METHODS
  RNC onlays (Lava Ultimate) (n=30) were treated using air abrasion with and without a universal adhesive, or HF etching followed by a universal adhesive with and without a silane coupling agent, or tribological silica coating with and without a universal adhesive, and divided into 6 groups. Onlays were luted with resin cement to dentin surfaces. A microtensile bond strength test was performed and evaluated by one-way ANOVA and Tukey HSD test (α=.05). A nanoscratch test, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy were used for micromorphologic analysis (α=.05). The roughness and elemental proportion were evaluated by Kruskal-Wallis test and Mann-Whitney U test.
  
  
  RESULTS
  Tribological silica coating showed the highest roughness, followed by air abrasion and HF etching. After HF etching, the RNC surface presented a decrease in oxygen, silicon, and zirconium ratio with increasing carbon ratio. Air abrasion with universal adhesive showed the highest bond strength followed by tribological silica coating with universal adhesive. HF etching with universal adhesive showed the lowest bond strength.
  
  
  CONCLUSIONS
  An improved understanding of the effect of surface treatment of RNC could enhance the durability of resin bonding when used for indirect restorations. When using RNC for restoration, effective and systemic surface roughening methods and an appropriate adhesive are required.
authors.affiliation: Department of Prosthodontics, College of Dentistry, Dankook University, Cheonan, Republic of Korea.
authors.forename: Joon-Ho
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Prosthodontics, College of Dentistry, Dankook University, Cheonan, Republic of Korea.
authors.forename: Yu-Sung
authors.identifier: 0000-0003-0053-7441
authors.initials: YS
authors.lastname: Choi
keywords: Ceramics; Computer-Aided Design-Computer-Aided Manufacturing (CAD-CAM); Morphologic analysis; Surface treatment; Tensile bond strength