title: In situ characterization of resin-dentin interfaces using conventional vs. cryofocused ion-beam milling.
abstract: OBJECTIVE
  The introduction of focused ion beam (FIB) milling has facilitated preparation of hard tissue samples for transmission electron microscope (TEM). However, this technique generates high temperature that may alter or damage morphological features in biological tissue. Therefore, the aim of this study was to determine the effects of cryogenic cooling on the morphological features of dentin interfaces with dental restorative materials in samples prepared by FIB for TEM examination.
  
  
  METHODS
  After preparation of a cylindrical-shaped cavities in extracted, non-carious premolar teeth, the specimens were restored with dental adhesive/composite and categorized into two restorative materials groups; (PB) a combination of Clearfil Protect Bond (Kuraray Noritake Dental, Japan)/Estelite Sigma Quick composite (Tokuyama Dental, Japan), and (SB) Filtek Silorane restorative system (3M ESPE, USA). The specimens were subjected to interfacial cross-sectioning, followed by observation and area selection using confocal laser microscopy. Later, ultrathin sections were prepared using FIB with cryogenic cooling (PB-C) and (SB-C), or without cooling (PB-NC) and (SB-NC) that all were examined under TEM.
  
  
  RESULTS
  Resulting TEM images of the ultra-morphological features at the resin-dentin nano-interaction zone were improved when FIB preparation was conducted in the cryogenic condition and no sign of artifacts were detected.
  
  
  CONCLUSIONS
  Conducting ion beam milling with cryogenic cooling was advantageous in minimizing the elevation in specimen temperature. This led to preservation of dentin microstructures that revealed additional information about substrates that are necessary for advanced characterization of tooth-biomaterial interactions.
authors.affiliation: Operative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, P.O. Box 80209, Jeddah 215-89, Saudi Arabia. Electronic address: taabakhsh@kau.edu.sa.
authors.forename: Turki A
authors.initials: TA
authors.lastname: Bakhsh
authors.affiliation: Cariology and Operative Dentistry Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan; University of Washington School of Dentistry, 1959 NE Pacific St, Seattle, WA 98195, United States.
authors.forename: Alireza
authors.initials: A
authors.lastname: Sadr
authors.affiliation: Cariology and Operative Dentistry Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors.forename: Mona M
authors.initials: MM
authors.lastname: Mandurah
authors.affiliation: Cariology and Operative Dentistry Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shimada
authors.affiliation: Oral Surgery, Faculty of Dentistry, Pharos University, 10 Elbostan St. Elmandara, Alexandria, Egypt.
authors.forename: Osama
authors.initials: O
authors.lastname: Zakaria
authors.affiliation: Cariology and Operative Dentistry Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
mesh_terms: D001641:Bicuspid; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry; D003804:Dentin / Q000737:chemistry*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D012117:Resins, Synthetic / Q000737:chemistry*; D062047:Silorane Resins / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature
chemical_list: C503075:Clearfil Protect Bond; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D012117:Resins, Synthetic; D062047:Silorane Resins; C527485:estelite flow quick; C555513:silorane composite resin
keywords: Collagen; Cryo; Dental adhesive; FIB; Hybrid layer; Resin composite; TEM; Teeth, dentin, nano-interaction zone