title: Regulated fracture in tooth enamel: a nanotechnological strategy from nature.
abstract: Tooth enamel is a very brittle material; however it has the ability to sustain cracks without suffering catastrophic failure throughout the lifetime of mechanical function. We propose that the nanostructure of enamel can play a significant role in defining its unique mechanical properties. Accordingly we analyzed the nanostructure and chemical composition of a group of teeth, and correlated it with the crack resistance of the same teeth. Here we show how the dimensions of apatite nanocrystals in enamel can affect its resistance to crack propagation. We conclude that the aspect ratio of apatite nanocrystals in enamel determines its resistance to crack propagation. According to this finding, we proposed a new model based on the Hall-Petch theory that accurately predicts crack propagation in enamel. Our new biomechanical model of enamel is the first model that can successfully explain the observed variations in the behavior of crack propagation of tooth enamel among different humans.
authors.affiliation: Faculty of Dentistry, McGill University, Montreal, QC, Canada H3A 0C7.
authors.forename: Elnaz
authors.initials: E
authors.lastname: Ghadimi
authors.affiliation: Faculty of Dentistry, McGill University, Montreal, QC, Canada H3A 0C7.
authors.forename: Hazem
authors.initials: H
authors.lastname: Eimar
authors.affiliation: Department of Mining and Materials Engineering, McGill University, Montreal, QC, Canada H3A 2A7.
authors.forename: Jun
authors.initials: J
authors.lastname: Song
authors.affiliation: Department of Mining and Materials Engineering, McGill University, Montreal, QC, Canada H3A 2A7.
authors.forename: Benedetto
authors.initials: B
authors.lastname: Marelli
authors.affiliation: Faculty of Dentistry, McGill University, Montreal, QC, Canada H3A 0C7.
authors.forename: Ovidiu
authors.initials: O
authors.lastname: Ciobanu
authors.affiliation: Faculty of Dentistry, McGill University, Montreal, QC, Canada H3A 0C7.
authors.forename: Mohamed-Nur
authors.initials: MN
authors.lastname: Abdallah
authors.affiliation: Department of Mining and Materials Engineering, McGill University, Montreal, QC, Canada H3A 2A7.
authors.forename: Christoph
authors.initials: C
authors.lastname: Stähli
authors.affiliation: Department of Mining and Materials Engineering, McGill University, Montreal, QC, Canada H3A 2A7.
authors.forename: Showan N
authors.initials: SN
authors.lastname: Nazhat
authors.affiliation: Faculty of Dentistry, McGill University, Montreal, QC, Canada H3A 0C7.
authors.forename: Hojatollah
authors.initials: H
authors.lastname: Vali
authors.affiliation: Faculty of Dentistry, McGill University, Montreal, QC, Canada H3A 0C7. Electronic address: faleh.tamimimarino@mcgill.ca.
authors.forename: Faleh
authors.initials: F
authors.lastname: Tamimi
mesh_terms: D001031:Apatites / Q000737:chemistry; D001696:Biomechanical Phenomena; D003460:Crystallization; D003743:Dental Enamel / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D012044:Regression Analysis; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D014070:Tooth; D014082:Tooth Fractures / Q000503:physiopathology*; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites
keywords: Apatite; Crack propagation; Crystal size; Enamel; Microhardness