title: Hardness and elasticity of sound and caries-affected primary dentin bonded with one-step self-etch adhesive.
abstract: Biomechanical properties of bonded dentin are important for resin restorations. We hypothesized that there are no differences in the hardness and elasticity of sound and caries-affected primary dentin bonded with a one-step self-etch adhesive. Resin-dentin interfaces in sound and caries-affected primary dentin were measured with a nano-indentation tester and observed with SEM and TEM. Interfacial dentin hardness was similar for sound and caries-affected dentin, but significantly lower than the underlying intact dentin. As for the Young's modulus of interfacial dentin, both substrates exhibited significantly lower values than the subsurface dentin. Further, the Young's modulus of interfacial dentin was significantly lower in caries-affected dentin. TEM revealed extensive interfacial nanoleakage in bonded sound dentin, while it was minimal in bonded caries-affected dentin. However, in the latter, silver deposits were identified within the porous substrate. Shorter application time and/or improvement of the adhesive components may be required to obtain stable adhesion in primary dentin.
authors: Department of Pediatric Dentistry, Course of Medical and Dental Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1, Sakamoto, Nagasaki 852-8588, Japan. hosoya@nagasaki-u.ac.jp
authors: Yumiko
authors: Y
authors: Hosoya
authors: Franklin R
authors: FR
authors: Tay
authors: Masashi
authors: M
authors: Miyazaki
authors: Takashi
authors: T
authors: Inoue
mesh_terms: D001840:Dental Bonding / Q000379:methods*; D003731:Dental Caries / Q000150:complications; D003763:Dental Leakage; D003804:Dentin / Q000737:chemistry* / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004548:Elasticity; D006244:Hardness; D006801:Humans; D036103:Nanotechnology; D013997:Time Factors
chemical_list: D017220:Dentin-Bonding Agents