Zinc-modified nanopolymers improve the quality of resin–dentin bonded interfaces
Demineralized collagen fibers at the hybrid layer are susceptible to degradation. Remineralization may aid to improve bond longevity.
The aim of the present study was to infiltrate zinc and calcium-loaded polymeric nanoparticles into demineralized dentin to facilitate hybrid layer remineralization.
Materials and methods
Zinc or calcium-loaded polymeric nanoparticles were infiltrated into etched dentin, and Single Bond Adhesive was applied. Bond strength was tested after 24 h and 6 months storage. Nanomechanical properties, dye-assisted confocal laser microscopy, and Masson’s trichrome staining evaluation were performed to assess for the hybrid layer morphology, permeability, and remineralization ability after 24 h and 3 months. Data were analyzed by ANOVA and Student–Newman–Keuls multiple comparisons tests (p < 0.05).
Immediate bond strength was not affected by nanoparticles infiltration (25 to 30 MPa), while after 6 months, bond strengths were maintained (22 to 24 MPa). After 3 months, permeability occurred only in specimens in which nanoparticles were not infiltrated. Dentin remineralization, at the bottom of the hybrid layer, was observed in all groups. After microscopy analysis, zinc-loaded nanoparticles were shown to facilitate calcium deposition throughout the entire hybrid layer. Young’s modulus at the hybrid layer increased from 2.09 to 3.25 GPa after 3 months, in specimens with zinc nanoparticles; meanwhile, these values were reduced from 1.66 to 0.49 GPa, in the control group.
Infiltration of polymeric nanoparticles into demineralized dentin increased long-term bond strengths. Zinc-loaded nanoparticles facilitate dentin remineralization within the complete resin–dentin interface.
Resin–dentin bond longevity and dentin remineralization at the hybrid layer were facilitated by zinc-loaded nanoparticles.
KeywordsRemineralization Zinc Nanopolymers Dentin Hybrid layer Adhesives
This work was supported by a grant, MINECO/FEDER MAT2014-52036-P. Authors do not have a financial relationship with the organization that sponsored the research.
Compliance with ethical standards
All procedures performed in the present study, involving human participants, were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.
This study was funded by the Ministerio Español de Economía y Competitividad, grant number MINECO/FEDER MAT2014-52036-P. Authors do not have a financial relationship with the organization that sponsored the research.
Conflict of interest
The authors declare that they have no competing interests.
Informed consent was obtained from all individual participants included in the study.
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