Engineered Peptide Repairs Defective Adhesive-Dentin Interface

Abstract

Failure of dental composite restorations is primarily due to recurrent decay at the tooth-composite interface. At this interface, the adhesive and its bond with dentin is the barrier between the restored tooth and the oral environment. In vivo degradation of the bond formed at the adhesive/dentin (a/d) interface follows a cascade of events leading to weakening of the composite restoration. Here, a peptide-based approach is developed to mineralize deficient dentin matrices at the a/d interface. Peptides that have an inherent capacity to self-assemble on dentin and to induce calcium-phosphate remineralization are anchored at the interface. Distribution of adhesive, collagen, and mineral is analyzed using micro-Raman spectroscopy and fluorescence microscopy. The analysis demonstrates remineralization of the deficient dentin matrices achieved throughout the interface with homogeneous distribution of mineral. The peptide-based remineralization demonstrated here can be an enabling technology to design integrated biomaterial-tissue interfaces.

Keywords: adhesive/dentin interface; composite restorative materials; material–tissue interface; mineralization; peptides.

Figure 1

Representative visible images to show the enlarged region from the adhesive/dentine interface. a,b) Original a/d interface. c) Additional etched a/d interface. d) Remineralization of the specimen by GFP-HABP. e,f) GFP-HABPs surface coverage by FM analysis. g) Extensively washed adhesive/dentin-specimen to remove excessive unbound protein. h) Mineralization a/d interface after remineralization.

Figure 2

a) Representative Raman XY imaging of the original a/d interface. b) The treated a/d interface specimens were analyzed using μRS and the absence of spectral features associated the mineral (PO₄⁻² at 962 cm⁻¹) indicates ≈10 μm demineralization.

Figure 3

a) Representative Raman XY imaging and b) the spectral analysis of the a/d interface following the additional etch. c) Raman XY imaging and d) the spectral analysis of the a/d interface after remineralization. The spectral features associated the mineral (PO₄⁻² at 962 cm⁻¹) show up after the remineralization following the addition etch.

Scheme 1

a) Adhesive/dentin interface - adapted with permission^[40] and Raman spectrum of adhesive and b) Raman spectrum of dentin.