TEM characterization of a silorane composite bonded to enamel/dentin.
OBJECTIVE
The low-shrinking composite composed of combined siloxane-oxirane technology (Filtek Silorane, 3M ESPE, Seefeld, Germany) required the development of a specific adhesive (Silorane System Adhesive, 3M ESPE), in particular because of the high hydrophobicity of the silorane composite. The purpose of this study was to characterize the interfacial ultra-structure at enamel and dentin using transmission electron microscopy (TEM).


METHODS
Non-demineralized/demineralized 70-90 nm sections were prepared following common TEM specimen processing procedures.


RESULTS
TEM revealed a typical twofold build-up of the adhesive resin, resulting in a total adhesive layer thickness of 10-20 microm. At bur-cut enamel, a tight interface without distinct dissolution of hydroxyapatite was observed. At bur-cut dentin, a relatively thin hybrid layer of maximum a few hundreds of nanometer was formed without clear surface demineralization. No clear resin tags were formed. At fractured dentin, the interaction appeared very superficial (100-200 nm). Distinct resin tags were formed due to the absence of smear plugs. Silver-nitrate infiltration showed a varying pattern of both spot- and cluster-like appearance of nano-leakage. Traces of Ag were typically detected along some part of the enamel-adhesive interface and/or between the two adhesive resin layers. Substantially more Ag-infiltration was observed along the dentin-adhesive interface of bur-cut dentin, as compared to that of fractured dentin.


CONCLUSIONS
The nano-interaction of Silorane System Adhesive should be attributed to its relatively high pH of 2.7. The obtained tight interface at both enamel and dentin indicates that the two-step self-etch adhesive effectively bridged the hydrophilic tooth substrate with the hydrophobic silorane composite.
Mine
Atsushi
A
Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Kapucijnenvoer 7, Leuven, Belgium.
De Munck
Jan
J
Van Ende
Annelies
A
Cardoso
Marcio Vivan
MV
Kuboki
Takuo
T
Yoshida
Yasuhiro
Y
Van Meerbeek
Bart
B
D000134:Acid Etching, Dental; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure*; D003747:Dental Enamel Solubility; D003763:Dental Leakage / Q000145:classification; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry; D005027:Ethylene Oxide / Q000737:chemistry; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D012828:Silicones / Q000737:chemistry; D062047:Silorane Resins; D016622:Silver Staining; D016369:Smear Layer; D013499:Surface Properties; D019246:Tooth Preparation / Q000295:instrumentation; D017155:Wettability; D015040:Zirconium / Q000737:chemistry
C112828:Clearfil AP-X; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C543062:Filtek LS Low Shrink resin; D008689:Methacrylates; D019279:Resin Cements; D012821:Silanes; D012828:Silicones; D062047:Silorane Resins; C083568:Z100 composite resin; C078211:polymethylsiloxane; D012822:Silicon Dioxide; D017886:Durapatite; D015040:Zirconium; D005027:Ethylene Oxide