Outcome of Different Processing Methods on Mechanical and Physicochemical Properties of Human Dentin as a Potential Natural Scaffold

Abstract

Dentin has been considered a promising scaffold for bone regeneration. This study investigated the effects of two different demineralization and deproteinization methods on the mechanical and physicochemical properties of dentin as a potential scaffold for tissue engineering approaches. Eighty dentin discs were divided into five groups according to the treatment process: control (C), no treatment; DEM1, complete demineralization with HCl; DEM2, partial demineralization with different concentrations of EDTA; DEP1, complete deproteinization using NaOCl solution; and DEP2, partial deproteinization by boiling water. The treated dentin discs were characterized using ATR-FTIR and SEM. The compressive strength, elastic modulus, and microhardness values of all C and treated samples were measured. They were analyzed using one-way ANOVA, Kruskal-Wallis, and Weibull analysis. FTIR showed significantly reduced mineral/matrix ratio in demineralized groups (DEM1 and 2) (p < 0.001), while increase of mineral/matrix ratio in DEP1 was not significant (p = 0.31). SEM observations revealed open dentinal tubules in DEM1 group and lower amounts in the other groups. The C showed the highest compressive strength (78.18 ± 16.19 MPa), and the DEM1 showed the lowest (0.84 ± 0.32 MPa). The treated groups showed lower Weibull moduli (m), when compared with the C group. The DEP2 (642 ± 318.9) and DEM1 (2.9 ± 1.37) groups showed the highest and lowest modulus of elasticity, respectively. DEM1 showed the least hardness values (10.27 ± 3.09) compared to the other groups (p < 0.001). Based on the results, the DEM1 showed confirmed demineralization and lowest mechanical properties. The highest mechanical properties belonged to DEM2 and DEP2 groups which both were partially treated. Depending on the purpose of the regeneration, the dentin processing method can be selected. Whenever the high mechanical properties are more important in scaffold selection, DEM2 and DEP2 are the best choices. This study investigated the effects of two different demineralization and deproteinization methods including DEM1, demineralization with HCl; DEM2, demineralization with EDTA; DEP1, deproteinization using NaOCl solution; and DEP2, deproteinization by boiling water on the mechanical and physicochemical properties of dentin as a potential scaffold. Based on the results, the DEM1 showed confirmed demineralization and lowest mechanical properties. The highest mechanical properties belonged to DEM2 and DEP2 groups which both were partially treated. Depending on the purpose of the regeneration, the dentin processing method can be selected. Whenever the high mechanical properties are more important in scaffold selection, DEM2 and DEP2 are the best choices. Future studies should be conducted to assess the osteoinductive/osteoconductive potential of these scaffolds and also cell growth and proliferation on the prepared scaffolds using mentioned protocols.