Journal of Dental Research, Vol 72, 1609-1613, Copyright © 1993 by International & American Associations for Dental Research Online Journals
Raman spectra of human dental calculus
H. Tsuda and J. Arends
Materia Technica, State University of Groningen, The Netherlands.
Raman spectra of human dental calculus have been observed for the first
time by use of micro-Raman spectroscopy. The spectral features of calculus
were influenced easily by heating caused by laser irradiation. Therefore,
the measurements were carried out at relatively low power (5 mW, 1-micron
spot size). The spectra could be characterized as phosphate vibrational
bands due to the v1, v2, v3, and v4 modes. The overall spectral features
did not resemble those of pure minerals such as brushite, octacalcium
phosphate, and hydroxyapatite. There were spectral differences among mixed
calculus particles obtained from 18 adults, probably due to variations in
local mineral composition and differences among patients. However, the
averaged spectral features did not vary significantly with formation period
from 1 to 6 months. Freshly removed and stored (5-11 months) calculus also
gave comparable Raman spectra. Measurements on a fractured sample indicated
that Raman spectra at saliva and dentin interfaces are nearly identical,
and major mineral constituents may not vary significantly along the growth
axis of calculus.
