Abstract
The correlation of carbonate content with enamel microstructure (chemical and crystal structure) and mechanical properties was evaluated via linear mapping analyses by Raman microspectroscopy and nanoindentation. Mappings started at the outer enamel surface and ended in the inner enamel near the dentin-enamel junction (DEJ) in lingual and buccal cervical and cuspal regions. The carbonate peak intensity at 1070 cm−1 gradually increased from outer to inner enamel. Moreover, the phosphate peak width, as measured by the full width at half maximum of the peak at 960 cm−1, also increased, going from ~9 cm−1 in outer enamel to ~13 cm−1 in enamel adjacent to the DEJ, indicating a decrease in the degree of crystallinity of hydroxyapatite from outer to inner enamel. In contrast, Young’s modulus decreased from 119 ± 12 to 80 ± 19 GPa across outer to inner enamel with a concomitant decrease in enamel hardness from 5.9 ± 1.4 to 3.5 ± 1.3 GPa. There were also significant correlations between carbonate content and associated crystallinity with mechanical properties. As carbonate content increased, there was an associated decrease in crystallinity and both of these changes correlated with decreased modulus and hardness. Collectively, these results suggest that enamel carbonate content and the associated change in the crystal structure of hydroxyapatite, i.e., degree of crystallinity, may have a direct effect on enamel mechanical properties. The combination of Raman microspectroscopy and nanoindentation proved to be an effective approach for evaluating the microstructure of enamel and its associated properties.
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References
Nanci A (2003) In: Nanci A (ed) Ten cate’s oral histology-development, structure, and function. Mosby, St Louis
Driessens FCM, Verbeeck RMH (1990) In: Driessens FCM, Verbeeck RMH (eds) Biominerals. CRC Press, Boca Raton
Brudevold F, Reda A, Aasenden R, Bakhos Y (1975) Arch Oral Biol 20:667. doi:10.1016/0003-9969(75)90135-1
Braly A, Darnell LA, Mann AB, Teaford MF, Weihs TP (2007) Arch Oral Biol 52:856. doi:10.1016/j.archoralbio.2007.03.005
He LH, Swain MV (2008) J Mech Behav Biomed Mater 1:18. doi:10.1016/j.jmbbm.2007.05.001
Lewis G, Nyman JS (2008) J Biomed Mater Res B Appl Biomater 87:286. doi:10.1002/jbm.b.31092
Angker L, Swain MV (2006) J Mater Res 21:1893. doi:10.1557/jmr.2006.0257
He LH, Swain MV (2009) J Dent 37:596. doi:10.1016/j.jdent.2009.03.019
Park S, Wang DH, Zhang D, Romberg E, Arola D (2008) J Mater Sci Mater Med 19:2317. doi:10.1007/s10856-007-3340-y
Cuy JL, Mann AB, Livi KJ, Teaford MF, Weihs TP (2002) Arch Oral Biol 47:281. doi:10.1016/S0003-9969(02)00006-7
Lee JJW, Morris D, Constantino PJ, Lucas PW, Smith TM, Lawn BR (2010) Acta Biomater 6:4560. doi:10.1016/j.actbio.2010.07.023
An B, Wang R, Arola D, Zhang D (2012) J Mech Behav Biomed Mater 9:63. doi:10.1016/j.jmbbm.2012.01.009
Sydney-Zax M, Mayer I, Deutsch D (1991) J Dent Res 70:913. doi:10.1177/00220345910700051001
SonJu Clasen AB, Ruyter IE (1997) Adv Dent Res 11:523. doi:10.1177/08959374970110042101
LeGeros RZ, Sakae T, Bautista C, Retino M, LeGeros JP (1996) Adv Dent Res 10:225. doi:10.1177/08959374960100021801
Sakae T (1988) Arch Oral Biol 33:707. doi:0003-9969(88)90003-9
Baena JR, Lendl B (2004) Curr Opin Chem Biol 8:534. doi:10.1016/j.cbpa.2004.08.014
Pappas D, Smith BW, Winefordner JD (2000) Talanta 51:131. doi:10.1016/s0039-9140(99)00254-4
Tsuda H, Arends J (1997) Adv Dent Res 11:539. doi:10.1177/08959374970110042301
Weatherell JA, Robinson C, Hiller CR (1968) Caries Res 2:1. doi:10.1159/000259538
Parayanthal P, Pollak FH (1984) Phys Rev Lett 52:1822. doi:10.1103/PhysRevLett.52.1822
Pucéat E, Reynard B, Lécuyer C (2004) Chem Geol 205:83. doi:10.1016/j.chemgeo.2003.12.014
Freeman JJ, Wopenka B, Silva MJ, Pasteris JD (2001) Calcif Tissue Int 68:156. doi:10.1007/s002230001206
Tesch W, Eidelman N, Roschger P, Goldenberg F, Klaushofer K, Fratzl P (2001) Calcif Tissue Int 69:147
Walker MP, Fricke BA (2006) In: Akay M (ed) Wiley encyclopedia of biomedical engineering. Wiley, Hoboken
White SN, Paine ML, Luo W, Sarikaya M, Fong H, Yu Z et al (2000) J Am Ceram Soc 83:238. doi:10.1111/j.1151-2916.2000.tb01181.x
Zaslansky P, Friesem AA, Weiner S (2006) J Struct Biol 153:188. doi:10.1016/j.jsb.2005.10.010
Suresh S (2001) Science 292:2447. doi:10.1126/science.1059716
Yurkstas AA (1965) J Prosthet Dent 15:248. doi:10.1016/0022-3913(65)90094-6
Ferrario VF, Sforza C, Zanotti G, Tartaglia GM (2004) J Dent 32:451. doi:10.1016/j.jdent.2004.02.009
Spears IR (1997) J Dent Res 76:1690. doi:10.1177/00220345970760101101
Saber-Samandari S, Gross KA (2009) Acta Biomater 5:2206. doi:10.1016/j.actbio.2009.02.009
Darnell LA, Teaford MF, Livi KJT, Weihs TP (2010) Am J Phys Anthropol 141:7. doi:10.1002/ajpa.21126
Zapanta-Legeros R (1965) Nature 206:403. doi:10.1038/206403a0
Gron P, Spinelli M, Trautz O, Brudevold F (1963) Arch Oral Biol 8:251. doi:10.1016/0003-9969(63)90016-5
Pan H, Darvell BW (2010) Cryst Growth Des 10:845. doi:10.1021/cg901199h
Sternlieb MP, Pasteris JD, Williams BR, Krol KA, Yoder CH (2010) Polyhedron 29:2364. doi:10.1016/j.poly.2010.05.001
Xu C, Karan K, Yao X, Wang Y (2009) J Raman Spectrosc 40:1780. doi:10.1002/jrs.2320
LeGeros RZ, Trautz OR, LeGeros JP, Klein E, Shirra WP (1967) Science 155:1409. doi:10.1126/science.155.3768.1409
Teraoka K, Ito A, Maekawa K, Onuma K, Tateishi T, Tsutsumi S (1998) J Dent Res 77:1560. doi:10.1177/00220345980770071201
Robinson C, Kirkham J, Brookes SJ, Bonass WA, Shore RC (1995) Int J Dev Biol 39:145
Margolis HC, Beniash E, Fowler CE (2006) J Dent Res 85:775. doi:10.1177/154405910608500902
Acknowledgements
This investigation was supported by the USPHS research grant DE021462 from the National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA. We also want to thank Dr. Ying Liu for her assistance with the statistical analyses.
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Xu, C., Reed, R., Gorski, J.P. et al. The distribution of carbonate in enamel and its correlation with structure and mechanical properties. J Mater Sci 47, 8035–8043 (2012). https://doi.org/10.1007/s10853-012-6693-7
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DOI: https://doi.org/10.1007/s10853-012-6693-7