Contributions of microstructure and chemical composition to the mechanical properties of dentin
- 267 Downloads
The influence of microstructural variations and chemical composition to the mechanical properties and apparent flaw sensitivity of dentin were evaluated. Rectangular beams (N = 80) of the deep and superficial coronal dentin were prepared from virgin 3rd molars; twenty beams of each region were nominally flaw free and the remainder possessed a single “surface flaw” via a Vickers indentation. Mechanical properties were estimated in four-point flexure and examined using Weibull statistics. Fourier Transform Infrared Microspectroscopy in Reflectance Mode (FTIR-RM) was used to quantify the relative mineral to collagen ratios. Results showed that the average flexural strength, and strain and energy to fracture of the deep dentin beams were significantly lower (P < 0.005) than for the superficial dentin. While the deep dentin exhibited the highest mineral/collagen ratio and lowest damage tolerance, there was no significant effect of the surface flaws. Weibull analyses suggest that deep dentin possesses a larger distribution of intrinsic flaw sizes that contributes to the location dependence in strength.
KeywordsDamage Dentin FTIR microspectroscopy Fracture Strength
This research was supported in part by an award from the National Institutes of Health (NIDCR DE016904) and the National Science Foundation (BES 0238237). Aftin Ross, Heon Ryou and Nikhil Amin were undergraduate students during the course of the research and Ms Ross acknowledges support from the MARC U-STAR program.
- 5.Sehy C, Drummond JL. Micro-cracking of tooth structure. Am J Dent. 2004;17(5):378–80.Google Scholar
- 15.ISO Standard 18756 (2003) Fine ceramics (advanced ceramics, advanced. technical ceramics)-determination of fracture. Toughness of monolithic ceramics at room temperature by the surface crack in flexure (SCF) method.Google Scholar
- 17.Peterson RE. Stress concentration factors. New York: Wiley; 1974.Google Scholar
- 18.Weibull W. A statistical distribution function of wide applicability. J Appl Mech. 1951;18:293–7.Google Scholar
- 21.Eidelman N, Simon CG. Characterization of combinatorial polymer blend composition gradients by FTIR Microspectroscopy. J Res Natl Inst Stand Technol. 2004;109(2):219–31.Google Scholar
- 26.Carvalho RM, Fernandes CA, Villanueva R, Wang L, Pashley DH. Tensile strength of human dentin as a function of tubule orientation and density. J Adhes Dent. 2001;3(4):309–14.Google Scholar
- 27.Inoue S, Pereira PN, Kawamoto C, Nakajima M, Koshiro K, Tagami J, Carvalho RM, Pashley DH, Sano H. Effect of depth and tubule direction on ultimate tensile strength of human coronal dentin. Dent Mater J. 2003;22(1):39–47.Google Scholar
- 39.Pashley DH. Smear layer: physiological considerations. Oper Dent. 1984;suppl 3:13–29.Google Scholar