Objectives. The aim of this study was to compare the type of information ob
tained from log-linear modelling vs Cohen's kappa statistics on observer Va
riation in the assessment of marginal adaptation in composite inlays and am
algam restorations.
Methods. Marginal adaptation of Class II resin composite inlays and amalgam
restorations was clinically assessed by two observers, four years after pl
acement. Each of 52 patients received 4 different restorations, three compo
site (Herculite XR, Clearfil CR Inlay and Visiomolar) inlays and one Tytin
restoration. The results were evaluated by Cohens Kappa statistics and log-
linear modelling.
Results. The overall Cohen's kappa was 0.45, ranging from poor to good for
the four materials. Log-linear modelling confirmed that the observers agree
d beyond chance but this agreement depended on the performance of the mater
ial. Marginal adaptation of Visiomolar (ESPE) inlays was somewhat inferior
compared to the other materials. The assessment of Clearfil CR (Kuraray) in
lay was difficult using this clinical evaluation procedure. Significance. U
sing log-linear modelling it is possible to look at observer agreement and
material performance at the same time. This combined approach is important
because agreement may depend on material performance.
(C) 1998 Academy of Dental Materials. Published by Elsevier Science Ltd.