Hertzian contact response of dentin with loading rate and orientation

Nelson Renato Franca Alves da Silva, F. Lalani, Paulo G. Coelho, Elizabeth A. Clark, Carlos Augusto de Oliveira Fernandes, Van P. Thompson

Research output: Contribution to journalArticlepeer-review


Objective: To test the hypothesis that dentin Hertzian contact response varies with loading rate and tubule orientation. Design: Sound teeth (n = 12) were cut either parallel or perpendicular to the axial direction to expose dentin (n = 6 each). The cut specimens were embedded (poly-methyl-methacrylate (PMMA) and divided into two groups: (GL) load applied parallel to dentin tubule direction and (GP) load applied perpendicular to tubule direction. A 1.5 mm diameter tungsten-carbide ball was used for Hertzian contact testing with a maximum load of 150 N load and loading rates of 0.1, 1, 100, and 1000 N/s on each specimen. Indented specimens were observed microscopically and photomicrographs acquired. Hertzian contact diameter and modulus were analysed (p < 0.05) by one-way ANOVA and Tukey test. Results: There were significant differences (p < 0.05) in Hertzian response with respect to loading rate for GL (0.1 N/s versus 1000 N/s, 0.1 N/s versus 100 N/s, 1 N/s versus 1000 N/s, and 1 N/s versus 100 N/s), and GP (0.1 N/s versus 1000 N/s, 0.1 N/s versus 100 N/s, and 1 N/s versus 1000 N/s). Contact modulus was higher for GL compared to GP at all loading rates (p < 0.05). Conclusion: The results suggest that dentin contact modulus is loading rate dependent. Tubule orientation of dentin did not influence contact modulus values (p > 0.05).

Original languageEnglish (US)
Pages (from-to)729-735
Number of pages7
JournalArchives of Oral Biology
Issue number8
StatePublished - Aug 2008


  • Dentin
  • Hertzian contact
  • Loading rate
  • Tubule orientation

ASJC Scopus subject areas

  • Otorhinolaryngology
  • General Dentistry
  • Cell Biology


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