Biomimetic dentin repair with a dual-analogue phosphate glass-polyacrylate paste: A proof-of-concept

Abstract

ObjectivesRecently, the trend in treating dental caries relies on preserving the affected dentin. The success of restorations relies on remineralization of affected dentin which is very challenging. Here, we report the facile development of a dual-analogue biomimetic phosphate glass polyacrylate paste (PGPAP), combining two non-collagenous protein precursors [sodium trimetaphosphate (STMP) and polyacrylic acid (PAA)], for remineralization of completely demineralized dentin. MethodsHuman mid-coronal dentin were excessively exposed to an acid challenge for 5 h to replicate affected dentin, in which the collagen matrix is not just partially demineralized but also degraded. To increase the challenge, the dentin samples coated with the PGPAP were kept in unfavorable mineralization buffer (demineralized water). The extent of de-/remineralization and elemental/chemical composition of dentin were investigated using confocal microscopy, scanning electron microscopy/energy dispersive X-ray, optical coherence tomography and Infra-red (FTIR). ResultsDentin, exposed to acidic challenge, showed a frayed and fully demineralized surface layer of 120 ± 30 μm with sub-surface partial demineralization of 100–300 μm. After 8 weeks of treatment with PGPAP, nearly all dentinal tubules and inter-tubular dentin were completely remineralized with an adherent layer of angular-like crystals. This layer contained Ca, P, Na and Cu and reached 313±6 μm in thickness ie, nearly all demineralized dentin becomes remineralized. After 4 weeks, the FTIR spectrum of treated dentin was consistent with native dentin. ConclusionsThe PGPAP might provide a solution towards the remineralization of the affected dentin produced by caries. This might be an ideal scenario for in-situ recapitulation of the original dentin properties towards a pre-carious (native) status.