Journal of Dental Research, Vol 72, 858-864, Copyright © 1993 by International & American Associations for Dental Research Online Journals
Simultaneous caries induction and calculus formation in rats
J. M. Tanzer, L. P. Grant, T. McMahon, D. Clinton and E. D. Eanes
School of Dental Medicine, University of Connecticut, Farmington 06030.
Weanling specific pathogen-free Osborne-Mendel rats were fed a
high-calcium, high-phosphorus diet with various levels of sucrose and
inoculated with Streptococcus sobrinus strain 6715-13WT and Actinomyces
viscosus strain OMZ-105 in order to determine whether calculus and caries
could develop simultaneously. Rats consumed diets designated RC-16-5,
RC-16-25, or RC-16-50 which partially replaced the corn starch component
with progressively higher levels of sucrose, thus, to 5, 25, or 50%
sucrose. In general, bacterial recoveries of A. viscosus declined with
higher sucrose content of the diet, but a pattern of recovery for S.
sobrinus was less clear with respect to dietary sucrose. S. sobrinus,
however, was recovered at higher percentages from the tooth surface flora
at the later two of three sampling dates. Most calculus--identified by the
brittle quality, staining characteristics, and apatitic x-ray diffraction
patterns of tooth surface deposits--was formed on the maxillary molars, and
most carious lesions occurred on mandibular molars. While there was minimal
association of the calculus score with the amount of sucrose in the diet,
calculus scores increased greatly from 23 to 43 days after infectious
challenge. Caries scores, of both fissure and smooth surfaces, by contrast,
increased in a dose-response fashion with increasing dietary sucrose and
with time. It is thus possible to induce calculus formation and caries
simultaneously in specific pathogen-free Osborne-Mendel rats consuming a
high-calcium and -phosphorus diet conducive to calculus formation and
containing sucrose.(ABSTRACT TRUNCATED AT 250 WORDS)
