Qualitative analysis of adhesive interface nanoleakage using FE-SEM/EDS.
OBJECTIVE
The purpose of this study was to evaluate the quality of short term sealing of current adhesives.


METHODS
Five adhesive systems were used and evaluated in this study; two kinds of two-step adhesives (Single Bond and Clearfil SE Bond) and three one-step adhesives (Clearfil S3 Bond, G Bond and One-Up Bond F-plus). Flat occlusal superficial dentin surfaces from extracted human third molars were finished with wet 600-grit silicon-carbide paper and bonded with one of the adhesives. After 24h storage at 37 degrees C in water, the bonded assemblies were sectioned into approximately 1mm thick slabs. Two central slabs from each tooth were chosen and immersed into 50% (w/v) solution of silver ammoniacal nitrate for 18 h and exposed to photodeveloping solution for 6h. The specimens were then slightly polished, argon ion-etched. In order to examine the nanoleakage within the resin/dentin interface, penetration of silver was observed in a field emission (FE)-SEM using yttrium-aluminium-garnet (YAG) backscattered electron mode. EDS analysis was also carried out in parallel to identify the existence of metallic silver particles.


RESULTS
The penetration pattern of silver depended on the adhesive used, indicating different nanoleakage in different adhesive systems. Single Bond, One-Up Bond F-plus and G Bond showed clear silver uptake in both the adhesive and hybrid layer. Clearfil SE Bond showed less silver penetration and slight silver peak on the elemental energy spectroscopy of EDS. Clearfil S3 Bond did not display clear silver penetration under 2000x magnification by FE-SEM, and no existence of metallic silver of the Clearfil S3 Bond group by EDS, could be detected.


CONCLUSIONS
The nanoleakage, as well as its location depends on the adhesives. Different nanoleakage expressions were revealed between two-step and one-step adhesives and also among one-step adhesives themselves.
Yuan
Yang
Y
Department of Cariology and Operative Dentistry, Tokyo Medical and Dental University, Tokyo, Japan. yuanyang.ope@gmail.com
Shimada
Yasushi
Y
Ichinose
Shizuko
S
Tagami
Junji
J
D000269:Adhesives / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D001840:Dental Bonding; D003763:Dental Leakage / Q000145:classification* / Q000473:pathology; D003764:Dental Materials / Q000737:chemistry; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology; D019279:Resin Cements / Q000737:chemistry; D012542:Scattering, Radiation; D016622:Silver Staining; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000269:Adhesives; C505694:Clearfil S3 Bond; C438313:Clearfil SE Bond; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C498353:G-Bond; D008689:Methacrylates; C446260:One-Up-Bond F; D019279:Resin Cements; C115612:single bond; D014867:Water; D017438:Bisphenol A-Glycidyl Methacrylate