Early dentine remineralisation: Morpho-mechanical assessment

Abstract

ObjectivesThe purpose of this study was to evaluate some physical–mechanical and morphological changes of demineralised dentine at early stages of dentine remineralisation. MethodsExtracted human third molars were sectioned to obtain dentine discs. After polishing the dentine surfaces, three groups were established: (1) untreated dentine – UD, (2) 37% phosphoric acid application for 15s (partially demineralised dentine – PDD) and (3) 10% phosphoric acid for 12h, at 25°C (totally demineralised dentine – TDD). Five different remineralizing fluids were used for 30min: chlorhexidine (CHX), artificial saliva (AS), phosphated solution (PS), ZnCl2 and ZnO solutions. Atomic force microscopy (AFM) imaging/nano-indentation, surface nano-roughness and fibrils diameter were determined. X-ray diffraction (XRD), energy dispersive elemental analyses (EDX) and high resolution scanning electron microscopy analysis (HRSEM) were applied. ResultsPDD and TDD preserved some mineral contents. After demineralisation and immersion in all solutions, width of nanomechanical properties and fibrils was increased, and total nanoroughness was decreased. Peritubular and intertubular dentine were remineralised. ConclusionMineral exists in PA-demineralised dentine matrix and it is important since it may work as a constant site for further nucleation. The dentine surface remineralisation process may be stimulated as early as 30min in abiotic conditions, with a pH ranging from 7.0 to 7.5. Clinical significanceThe existence of enzymes and remineralising factors within the dentine matrix may facilitate early dentine remineralisation under favourable conditions. This process should be stimulated by new reparative materials.