Advances in Dental Research, Vol 8, 125-133, Copyright © 1994 by International & American Associations for Dental Research
In situ models, physico-chemical aspects
J. M. ten Cate
Department of Cardiology and Endodontology, Academic Centre for Dentistry, Amsterdam, the Netherlands.
In situ (intra-oral) caries models are used for two purposes. First, they
provide information about oral physiological processes. Such information
helps to detail our knowledge of the oral ecosystem and to verify
conclusions from in vitro experiments. Second, in situ models are utilized
to test preventive agents in the phase between laboratory testing and
clinical trials. Most investigations involving enamel inserts have been
aimed at testing new dentifrices. The experimental designs of such studies
usually do not allow one to draw conclusions on physico-chemical processes,
e.g., because of single point measurements. Studies of model parameters
(lesion type, lesion severity, and de/remineralization in time) constitute
only a minority of the research reports. The most striking observation
obtained with in situ models has been the significant differences in
de/remineralization observed among individuals and, more importantly,
within one individual during different time periods and between different
sites in the same mouth (for review, see ten Cate et al., 1992). Regardless
of this, some general findings can be inferred: During in situ
demineralization, up to 62 vol% microns/day may be removed from enamel. For
dentin specimens, this value may be as high as 89 vol% microns/day. For
remineralization, during fluoride dentifrice treatment, a median deposition
rate of 0.7%/day (for lesions with integrated mineral loss values between
2000 and 4000 vol% microns) is found. The rate of deposition seems to be
correlated with the extent of the pre-formed lesion. This suggests that the
number of sites (crystallite surface) available for calcium phosphate
precipitation is an important parameter.(ABSTRACT TRUNCATED AT 250 WORDS)
