Non-Collagenous Dentin Protein Binding Sites Control Mineral Formation during the Biomineralisation Process in Radicular Dentin

Abstract

The biomineralisation of radicular dentin involves complex molecular signalling. Providing evidence of protein binding sites for calcium ions and mineral precipitation is essential for a better understanding of the remineralisation process. This study aimed to evaluate the functional relationship of metalloproteinases (MMPs) and non-collagenous proteins (NCPs) with mineral initiation and maturation during the biomineralisation of radicular dentin. A standardized demineralisation procedure was performed to radicular dentin slices. Samples were remineralised in a PBS-bioactive material system for different periods of time. Assessments of ion exchange, Raman analysis, and energy dispersive X-ray analysis (EDAX) with a scanning electron microscope (SEM) were used to evaluate the remineralisation process. Immunohistochemistry and zymography were performed to analyse NCPs and MMPs expression. SEM evaluation showed that the mineral nucleation and growth occurs, exclusively, on the demineralised radicular dentin surface. Raman analysis of remineralised dentin showed intense peaks at 955 and 1063 cm−1, which can be attributed to carbonate apatite formation. Immunohistochemistry of demineralised samples revealed the presence of DMP1-CT, mainly in intratubular dentin, whereas DSPP in intratubular and intertubular dentin. DMP1-CT and DSPP binding sites control carbonate apatite nucleation and maturation guiding the remineralisation of radicular dentin.

Push-Out Bond Strength, Characterization, and Ion Release of Premixed and Powder-Liquid Bioceramic Sealers with or without Gutta-Percha

“…The continuous setting of calcium silicate-based sealers in the process of hydration and ion exchange with the medium could be related to the improvement of the bond strength and the stability of the sealing provided by the root canal filling in the long term [ 10 , 12 , 17 , 33 ].…”

Sodium Hypochlorite and Chlorhexidine Downregulate MMP Expression on Radicular Dentin

“…Type I collagen is the major constituent (∼90%) of the ECM, conferring dentin with most of its functional properties. On the other hand, noncollagenous proteins (NCPs) (∼10%) play fundamental roles during dentinogenesis and pathophysiological processes [1][2][3]. NCPs are synthesized and secreted by odontoblasts which remain embedded in ECM [1,4].…”

“…NCPs are synthesized and secreted by odontoblasts which remain embedded in ECM [1,4]. Thus, the dentin matrix is a reservoir of NCPs including enzymes that act as signaling molecules in biomineralization of the dentin and bone [2,5,6].…”

“…Mineralization of hard tissues is a complex biological process that requires active extracellular enzymatic control, which is mainly performed by different proteinase members of the matrix metalloproteinase (MMP) family [2,5,7]. MMPs cleave specific substrates involved in cell signaling, tissue development/remodeling, and tissue breakdown in pathological processes [2][3][4]7]. Among MMPs, MMP-2, MMP-8, MMP-9, and MMP-20 in their active or latent forms have been isolated from the mature human mineralized and demineralized dentin matrix [2,4,[8][9][10].…”

“…MMPs cleave specific substrates involved in cell signaling, tissue development/remodeling, and tissue breakdown in pathological processes [2][3][4]7]. Among MMPs, MMP-2, MMP-8, MMP-9, and MMP-20 in their active or latent forms have been isolated from the mature human mineralized and demineralized dentin matrix [2,4,[8][9][10]. Endogenous MMP activity within dentin is mostly related to its ability to degrade all ECM components influencing dental tissue formation and mineralization and showed a regulatory effect on the differentiation of mesenchymal stem cells [3,[11][12][13][14].…”