Hostname: page-component-5d59c44645-dknvm Total loading time: 0 Render date: 2024-02-25T12:53:51.456Z Has data issue: false hasContentIssue false

Comparison of mechanical behaviors of enamel rod and interrod regions in enamel

Published online by Cambridge University Press:  03 January 2012

Siang Fung Ang
Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg 21073, Germany
Mahnaz Saadatmand
Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg 21073, Germany
Michael V. Swain
Biomaterials Science Research Unit, Faculty of Dentistry, University of Sydney, New South Wales 2006, Australia; and Department of Oral Sciences, University of Otago, Dunedin 9054, New Zealand
Arndt Klocke
Division of Orthodontics, Department of Orofacial Sciences, University of California, San Francisco, California 94143; and Department of Orthodontics, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
Gerold A. Schneider*
Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg 21073, Germany
a)Address all correspondence to this author. e-mail:
Get access


Interrod regions exist between the enamel rods and are known to have different crystallite orientations and a higher organic content compared to the enamel rods (the intrarod regions). This study aims to characterize the mechanical properties of both regions especially the time-dependent properties by using spherical indentation. Despite the very small amount of proteins, the interrod region shows statistically significantly higher inelastic energy dissipation than the intrarod region with increased deformation times. The total displacement under constant load (creep), viscosity, and stress relaxation behavior of both regions are also reported. Similar to the observation of previous studies, the elastic modulus and hardness in the intrarod region are significantly higher than in the interrod region.

Copyright © Materials Research Society 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)



1.Healy, K.E.: Dentin and enamel, in Handbook of Biomaterials Properties, edited by Black, J. and Hastings, G. (Chapman & Hall, London, 1995), p. 25.Google Scholar
2.Frazier, P.D.: Adult human enamel: An electron microscopic study of crystallite size and morphology. J. Ultrastruct. Res. 22, 1 (1968).CrossRefGoogle ScholarPubMed
3.Daculsi, G. and Kerebel, B.: High-resolution electron microscope study of human enamel crystallites: Size, shape, and growth. J. Ultrastruct. Res. 65, 163 (1978).CrossRefGoogle ScholarPubMed
4.Gray, H., Bannister, L.H., Berry, M.M., and Williams, P.L.: Gray’s Anatomy: The Anatomical Basis of Medicine & Surgery, 38th ed. (Churchill Livingstone, New York, 1995), p. 1710.Google Scholar
5.Nanci, A.: Ten Cate’s Oral Histology: Development, Structure, and Function (Mosby, St Louis, 2003).Google Scholar
6.Bajaj, D. and Arola, D.D.: On the R-curve behavior of human tooth enamel. Biomaterials 30, 4037 (2009).CrossRefGoogle ScholarPubMed
7.Glimcher, M.J., Daniel, E.J., Travis, D.F., and Kamhi, S.: Electron optical and x-ray diffraction studies of the organization of the inorganic crystals in embryonic bovine enamel. J. Ultrastruct. Res. 50, 1 (1965).CrossRefGoogle ScholarPubMed
8.Maas, M.C. and Dumont, E.R.: Built to last: The structure, function and evolution of primate dental enamel. Evol. Anthropol. 8, 133 (1999).3.0.CO;2-F>CrossRefGoogle Scholar
9.Carlisle, C.R., Coulais, C., and Guthold, M.: The mechanical stress-strain properties of single electrospun collagen type I nanofibers. Acta Biomater. 6, 2997 (2010).CrossRefGoogle ScholarPubMed
10.Habelitz, S., Marshall, S.J., Marshall, G.W. Jr., and Balooch, M.: Mechanical properties of human dental enamel on the nanometre scale. Arch. Oral Biol. 46, 173 (2001).CrossRefGoogle ScholarPubMed
11.Ge, J., Cui, F.Z., Wang, X.M., and Feng, H.L.: Property variations in the prism and the organic sheath within enamel by nanoindentation. Biomaterials 26, 3333 (2005).CrossRefGoogle ScholarPubMed
12.Oyen, M. and Cook, R.F.: A practical guide for analysis of nanoindentation data. J. Mech. Behav. Biomed. Mater. 2(4), 396 (2009).CrossRefGoogle ScholarPubMed
13.Mencik, J., He, L.H., and Swain, M.V.: Determination of viscoelastic-plastic material parameters of biomaterials by instrumented indentation. J. Mech. Behav. Biomed. Mater. 2, 318 (2009).CrossRefGoogle ScholarPubMed
14.Oyen, M.L.: Spherical indentation creep following ramp loading. J. Mater. Res. 20(8), 2094 (2005).CrossRefGoogle Scholar
15.Oyen, M.L. and Cook, R.F.: Load–displacement behavior during sharp indentation of viscous–elastic–plastic materials. J. Mater. Res. 18(1), 139 (2003).CrossRefGoogle Scholar
16.Olesiak, S.E., Oyen, M.L., and Ferguson, V.L.: Viscous-elastic-plastic behavior of bone using Berkovich nanoindentation. Mech. Time-Depend. Mater. 14, 111 (2010).CrossRefGoogle Scholar
17.Hertz, H.R.: Miscellaneous Papers (Macmillan, London, 1896).Google Scholar
18.Field, J.S. and Swain, M.V.: A simple predictive model for spherical indentation. J. Mater. Res. 8, 297 (1993).CrossRefGoogle Scholar
19.Oliver, W.C. and Pharr, G.M.: An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7, 1564 (1992).CrossRefGoogle Scholar
20.He, L.H. and Swain, M.V.: Energy absorption characterization of human enamel using nanoindentation. J. Biomat. Mater. Res. 81, 484 (2007).CrossRefGoogle ScholarPubMed
21.Lee, E.H. and Radok, J.R.M.: The contact problem for viscoelastic bodies. J. Appl. Mech. 27, 438 (1960).CrossRefGoogle Scholar
22.Johnson, K.L.: Contact Mechanics (Cambridge University Press, Cambridge, 1985).CrossRefGoogle Scholar
23.Oyen, M.L.: Analytical techniques for indentation of viscoelastic materials. Philos. Mag. 86, 5625 (2006).CrossRefGoogle Scholar
24.Sakai, M. and Shimizu, S.: Indentation rheometry for glass-forming materials. J. Non-Cryst. Solids 282, 236 (2001).CrossRefGoogle Scholar
25.He, L.H. and Swain, M.V.: Nanoindentation creep behavior of human enamel. J. Mech. Behav. Biomed. Mater. 91, 352 (2009).Google ScholarPubMed
26.Williams, G. and Watts, D.C.: Non-symmetrical dielectric relaxation behavior arising from a simple empirical decay function. Trans. Faraday Soc. 66, 80 (1970).CrossRefGoogle Scholar
27.Dorrington, K.L.: The theory of viscoelasticity in biomaterials. Symp. Soc. Exp. Biol. 34, 289 (1980).Google ScholarPubMed
28.Ang, S.F., Bortel, E.L., Swain, M.V., Klocke, A., and Schneider, G.A.: Size-dependent elastic/inelastic behavior of enamel over millimeter and nanometer length scales. Biomaterials 31, 1955 (2010).CrossRefGoogle ScholarPubMed
29.Habelitz, S., Marshall, G.W., Balooch, M., and Marshall, S.J.: Nanoindentation and storage of teeth. J. Biomech. 35(7), 995 (2002).CrossRefGoogle ScholarPubMed
30.Viswanath, B., Raghavan, R., Ramamurty, U., and Ravishankar, N.: Mechanical properties and anisotropy in hydroxyapatite single crystals. Scr. Mater. 57, 361 (2007).CrossRefGoogle Scholar
31.Dougan, L., Koti, A.S., Genchev, G., Lu, H., and Fernandez, J.M.: A single-molecule perspective on the role of solvent hydrogen bonds in protein folding and chemical reactions. ChemPhysChem. 9, 2836 (2008).CrossRefGoogle ScholarPubMed
32.Zhang, J., Michalenko, M.M., Kuhl, E., and Ovaert, T.C.: Characterization of indentation response and stiffness reduction of bone using a continuum damage model. J. Mech. Behav. Biomed. Mater. 3, 189 (2010).CrossRefGoogle ScholarPubMed
33.He, L.H. and Swain, M.V.: Influence of environment on the mechanical behaviour of mature human enamel. Biomaterials 28, 4512 (2007).CrossRefGoogle ScholarPubMed
34.Schneider, G.A., He, L.H., and Swain, M.V.: Viscous flow model of creep in enamel. J. Appl. Phys. 103, 014701 (2008).CrossRefGoogle Scholar