Hardness and indentation modulus of human enamel and dentin

Abstract

Information on mechanical properties of human enamel and dentin and effect of load on their deformation and damage tolerance is very important in the development of successful dental materials. In this study, the hardness, indentation modulus and deformation characteristics of tooth have been investigated across the lingual–buccal enamel and dentin cross‐section by instrumented indentation up to 1500‐nm indentation depth. We realized and examined the distribution of hardness and modulus at different areas of enamel and dentin with the aim to understand deformation behaviour at these different locations. Scanning electron microscopy was used for the microstructure characterization of the enamel and dentin and their deformation behaviour. Raman spectroscopy analyses were carried out for determination of the enamel and dentin composition as well. The average values of hardness and modulus for enamel in the occlusal area are 5.35 ± 0.19 and 98.1 ± 1.5 GPa, in the inner area 3.68 ± 0.5 and 81.8 ± 5 GPa and in the area close to the dentin–enamel junction 2.83 ± 0.27 and 71.4 ± 4.1 GPa, respectively. The average values of hardness and modulus of dentin in the area close to the dentin–enamel junction are 0.71 ± 0.05 and 21.27 ± 0.76 GPa and in the inner area 0.65 ± 0.06 and 19.79 ± 0.93 GPa, respectively. The effect of the indentation location on deformation and mechanical properties was clarified.

Peptide Amphiphile‐Mediated Assembly and Fusion of Anisotropic Amorphous Particles for Enamel Remineralization

“…The sound enamel exhibited excellent material performance, with an H of 4.14 ± 0.64 GPa (mean ± SD) and an E of 90.97 ± 12.12 GPa, which was consistent with previously reported results (Figure 4b). [ 52 ] However, the H and E values of the acid‐etched enamel were considerably reduced to 0.15 ± 0.01 GPa and 17.26 ± 2.06 GPa, respectively, because acid etching destroyed the structure and caused the surface to become incompacted (Figure 3a,b). Since enamel could act as a template to induce the heterogeneous nucleation of calcium phosphate in the m‐SBF and form a new mineral layer but with a disordered structure, mineral deposition improved the H (0.74 ± 0.14 GPa) and E (40.91 ± 2.43 GPa) values, but they remained significantly lower than those of natural enamel.…”

Effect of the Abutment Rigidity on the Wear Resistance of a Lithium Disilicate Glass Ceramic: An In Vitro Study

“…For LDS-on-Tooth-Replica, a model of a tooth was designed digitally on the basis of mean dimensions of a second maxillary premolar [ 54 ]. The preparation for a full crown with a thickness reduction of 2 mm occlusally and 1.5 mm axially and a total occlusal convergence angle of 8° was designed and milled from a hybrid glass ceramic material (Ambarino High Class, Creamed GmbH & Co., Marburg, Germany) with mechanical properties comparable to human dentin (hardness compared to natural dentin was 710 MPa and 650 MPa, respectively, while modulus of elasticity was 10 GPa and 16.5 Gpa [ 55 , 56 ]). Cubic PMMA blocks with dimensions of 20 × 12 × 12 mm were milled to create a replica of the socket, leaving a space between the tooth root and the socket wall.…”