The fracture behaviour of dental enamel

Enamel is the hardest tissue in the human body covering the crowns of teeth. Whereas the underlying dental material dentin is very well characterised in terms of mechanical and fracture properties, available data for enamel are quite limited and are apart from the most recent investigation mainly based on indentation studies. Within the current study, stable crack-growth experiments in bovine enamel have been performed, to measure fracture resistance curves for enamel. Single edge notched bending specimens (SENB) prepared out of bovine incisors were tested in 3-point bending and subsequently analysed using optical and environmental scanning electron microscopy. Cracks propagated primarily within the protein-rich rod sheaths and crack propagation occurred under an inclined angle to initial notch direction not only due to enamel rod and hydroxyapatite crystallite orientation but potentially also due to protein shearing. Determined mode I fracture resistance curves ranged from 0,8 – 1,5 MPa*m1/2 at the beginning of crack propagation up to 4,4 MPa*m1/2 at 500 m crack extension; corresponding mode II values ranged from 0,3 to 1,5 MPa*m1/2.

Subjects

enamel, mechanical properties, fracture behaviour, resistance curves, toughening

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http://doku.b.tu-harburg.de/doku/lic_ohne_pod.php

Name

Bechtle_et_al_The_Fracture_Behaviour_of_Dental_Enamel_Biomaterials_2010.pdf

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2.07 MB

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The fracture behaviour of dental enamel