Terahertz pulsed imaging study to assess remineralization of artificial caries lesions

David Churchley, Richard J.M. Lynch, Frank Lippert, Jennifer Susan O.Bryan Eder, Jesse Alton, Carlos Gonzalez-Cabezas

Research output: Contribution to journalArticle

21 Scopus citations


We compare terahertz-pulsed imaging (TPI) with transverse microradiography (TMR) and microinden-tation to measure remineralization of artificial caries lesions. Lesions are formed in bovine enamel using a solution of 0.1 M lactic acid/0.2% Carbopol C907 and 50% saturated with hydroxyapatite adjusted to pH 5.0. The 20-day experimental protocol consists of four 1 min treatment periods with dentifrices containing 10, 675, 1385, and 2700 ppm fluoride, a 4-h/day acid challenge, and, for the remaining time, specimens are stored in a 50:50 pooled human/artificial saliva mixture. Each specimen is imaged at the focal point of the terahertz beam (data-point spacing = 50 μm). The time-domain data are used to calculate the refractive index volume percent profile throughout the lesion, and the differences in the integrated areas between the baseline and post-treatment profiles are used to calculate ΔΔZ (THz). In addition, the change from baseline in both the lesion depth and the intensity of the reflected pulse from the air/enamel interface is determined. Statistically significant Pearson correlation coefficients are observed between TPI and TMR/microindentation (P < 0.05). We demonstrate that TPI has potential as a research tool for hard tissue imaging.

Original languageEnglish (US)
Article number026001
JournalJournal of Biomedical Optics
Issue number2
StatePublished - Feb 1 2011


  • Caries
  • Microindentation
  • Microradiography
  • Remineralization
  • Terahertz imaging

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering

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    Churchley, D., Lynch, R. J. M., Lippert, F., Eder, J. S. O. B., Alton, J., & Gonzalez-Cabezas, C. (2011). Terahertz pulsed imaging study to assess remineralization of artificial caries lesions. Journal of Biomedical Optics, 16(2), [026001]. https://doi.org/10.1117/1.3540277