title: Paucity of Nanolayering in Resin-Dentin Interfaces of MDP-based Adhesives.
abstract: Self-assembled nanolayering structures have been reported in resin-dentin interfaces created by adhesives that contain 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP). These structures have been hypothesized to contribute to bond durability. The objective of the present study was to determine the extent of nanolayering in resin-dentin interfaces after application of commercialized 10-MDP-containing self-etch and universal adhesives to human dentin. Seven commercialized adhesives were examined: Adhese Universal (Ivoclar-Vivadent), All-Bond Universal (Bisco, Inc.), Clearfil SE Bond 2, Clearfil S3 Bond Plus, Clearfil Universal Bond (all from Kuraray Noritake Dental Inc.), G-Premio Bond (GC Corp.), and Scotchbond Universal (3M ESPE). Each adhesive was applied in the self-etch mode on midcoronal dentin according to the respective manufacturer's instructions. Bonded specimens (n = 6) were covered with flowable resin composite, processed for transmission electron microscopy, and examined at 30 random sites without staining. Thin-film glancing angle X-ray diffraction (XRD) was used to detect the characteristic peaks exhibited by nanolayering (n = 4). The control consisted of 15%wt, 10%wt, and 5%wt 10-MDP (DM Healthcare Products, Inc.) dissolved in a mixed solvent (ethanol and water weight ratio 9:8, with photoinitiators). Experimental primers were applied to dentin for 20 s, covered with hydrophobic resin layer, and examined in the same manner. Profuse nanolayering with highly ordered periodicity (~3.7 nm wide) was observed adjacent to partially dissolved apatite crystallites in dentin treated with the 15% 10-MDP primer. Three peaks in the 2θ range of 2.40° (3.68 nm), 4.78° (1.85 nm), and 7.18° (1.23 nm) were identified from thin-film XRD. Reduction in the extent of nanolayering was observed in the 10% and 5% 10-MDP experimental primer-dentin interface along with lower intensity XRD peaks. Nanolayering and characteristic XRD peaks were rarely observed in specimens prepared from the commercialized adhesives. The sparsity of nanolayering in resin-dentin interfaces created by commercialized adhesives challenges its clinical effectiveness as a mechanism for improving bond longevity in dentin bonding.
authors.affiliation: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing, PR China.
authors.forename: F
authors.initials: F
authors.lastname: Tian
authors.affiliation: Key Laboratory for Oral Biomedical Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, PR China.
authors.forename: L
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Prosthodontics, Zhejiang University School and Hospital of Stomatology, Hangzhou, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Military Stomatology, School of Stomatology, The Fourth Military Hospital, Xi'an, Shaanxi, China.
authors.forename: L
authors.initials: L
authors.lastname: Niu
authors.affiliation: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing, PR China.
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Operative Dentistry & Endodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, PR China.
authors.forename: C
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing, PR China.
authors.forename: J
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Key Laboratory for Oral Biomedical Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, PR China.
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing, PR China.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Prosthodontics, Zhejiang University School and Hospital of Stomatology, Hangzhou, China.
authors.forename: B
authors.initials: B
authors.lastname: Fu
authors.affiliation: Key Laboratory for Oral Biomedical Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, PR China.
authors.forename: C
authors.initials: C
authors.lastname: Huang
authors.affiliation: The Dental College of Georgia, Augusta University, Augusta, GA, USA.
authors.forename: D H
authors.initials: DH
authors.lastname: Pashley
authors.affiliation: The Dental College of Georgia, Augusta University, Augusta, GA, USA ftay@gru.edu.
authors.forename: F R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D003743:Dental Enamel / Q000737:chemistry* / Q000648:ultrastructure; D003804:Dentin / Q000737:chemistry* / Q000648:ultrastructure; D006801:Humans; D066298:In Vitro Techniques; D008689:Methacrylates / Q000737:chemistry*; D008854:Microscopy, Electron; D008964:Molar, Third; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D019279:Resin Cements / Q000737:chemistry*; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D008689:Methacrylates; D019279:Resin Cements; C069749:methacryloyloxydecyl dihydrogen phosphate
keywords: 10-MDP; dental bonding; functional monomer; methacryloyloxydecyl dihydrogen phosphate; transmission electron microscopy; x-ray diffraction