Relationship between water status in dentin and interfacial morphology in all-in-one adhesives.
OBJECTIVE
All-in-one adhesive systems have been recently developed to simplify bonding procedures. The adhesives containing acidic resin monomers generate a relatively thin bonding zone between dentin and composite. This zone may be left acidic and permeable when polymerization is poor. In this study, the effect of water contained in dentin on the quality of the bonding interface was morphologically investigated for all-in-one adhesives.


METHODS
Intact coronal dentin (hydrated dentin), desiccated coronal dentin (dehydrated dentin), caries-affected dentin (CAD) and resin composites were used for adherends to assess the effects of water contained in dentin on the ultra-structures of bonding interfaces created with two all-in-one adhesives and a resin composite.


RESULTS
The bonding interfaces were observed under TEM without demineralization. Voids of various sizes were found at the bottom of the adhesive resin layers along the bonding interface of hydrated dentin, while dehydrated dentin, CAD and resin composites did not generate voids. The results showed that the voids were possibly formed by water that had penetrated from the underlying dentin.


CONCLUSIONS
When the adherend contains little water, the formation of voids will not occur. It was verified that a phenomenon of void formation would not occur in a clinical situation in which caries-affected dentin is mainly subjected to adhesive practices.
Yoshida
Eiji
E
Department of Dental Engineering, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Yokohama 230-8501, Japan. yoshida-e@tsurumi-u.ac.jp
Uno
Sigeru
S
Nodasaka
Yoshinobu
Y
Kaga
Msayuki
M
Hirano
Susumu
S
D000143:Acids / Q000737:chemistry; D000269:Adhesives / Q000737:chemistry; D001834:Body Water / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003731:Dental Caries / Q000473:pathology; D003804:Dentin / Q000737:chemistry / Q000648:ultrastructure*; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D003890:Desiccation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008689:Methacrylates / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D019279:Resin Cements / Q000737:chemistry; D013499:Surface Properties
C453842:AQ bond; D000143:Acids; D000269:Adhesives; C503075:Clearfil Protect Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; C090890:Metafil A