Journal of Dental Research, Vol 64, 102-105, Copyright © 1985 by International & American Associations for Dental Research Online Journals
Analysis of covariance in caries clinical trials using groupings of teeth
H. V. Worthington and B. L. Adkins
An empirical investigation was carried out on data from four caries
clinical trials of subjects who were initially 11 to 12 years old. The
three baseline variables suggested by Adkins (1977), as possibly being
related to caries increment, were each calculated on specific groupings of
teeth, and these were then considered as predictor variables for the
dependent variable, caries increment. A gain in efficiency of approximately
20% was obtained when an analysis of covariance was used with these
predictor variables, over a straightforward analysis of variance. However,
this was only slightly more efficient than using baseline DMFS as a
covariable. This investigation did not support the results of initial work
done by Adkins (1977).
