A natural biomimetic porous medium mimicking hypomineralized enamel

Elsa Vennat (1) , Maud Denis (1, 2) , Bertrand David (1) , Jean-Pierre Attal (2)

1 MSSMat - Laboratoire de mécanique des sols, structures et matériaux
2 URB2i - EA 4462 - Unité de Recherche Biomatériaux Innovants et Interfaces

Objectives In order to evaluate the clinical impact of low viscosity resin infiltration in hypomineralized enamel, it is necessary to obtain a biomimetic porous substrate capable of mimicking enamel. The specifications for the biomimetic porous medium are defined using the literature data on hypomineralized enamel. Based on these specifications, we propose to use deproteinized dentin, the latter being deproteinized by heat treatment. Methods and Results Thermogravimetry analysis (TGA), field emission scanning electron microscopy (FESEM) observations, mercury intrusion porosimetry (MIP) tests and nanoindentation are performed on the deproteinized dentin tissue. Heat treatment is shown to be an effective and reproducible method for removing organic fluids and protein residues in dentin. Deproteinizing dentin also enables forming nanovoids by eliminating its organic matrix. The interconnected open nanoporosities (porosities of less than 100 nm) created at 600 °C are distributed between 14 nm and 32 nm and the total porosity is 39% (including 36% due to nanoporosities). At 800 °C, they are distributed between 60 nm and 100 nm and total porosity is 37% (including 33% arising from the nanoporosities). The hydroxyapatite crystal structure is transformed less at 600 °C, so this temperature should be preferred. Significance Besides providing new understanding of the dentin tissue itself, this study led to characterizing a porous medium made of natural apatite, and proposing and validating its use as a porous medium mimicking hypomineralized enamel. The next logical step of this study is the characterization of resin infiltration in this medium and its mechanical reinforcement.

Mots clés: hypomineralized enamel; biomimetics; minimally invasive dentistry; mineral porous medium; hydroxyapatite; deproteinized dentin; porosimetry; thermogravimetry; nanoindentation; SEM; tissue engineering; porous scaffold

Domaines: Mécanique des matériaux [physics.class-ph]; Biomécanique [physics.med-ph]; Matériaux; Biomatériaux

Elsa Vennat, Maud Denis, Bertrand David, Jean-Pierre Attal. A natural biomimetic porous medium mimicking hypomineralized enamel. Dental Materials, 2015, 31 (3), pp.225-234. ⟨10.1016/j.dental.2014.12.008⟩. ⟨hal-01100634⟩