Journal of Dental Research, Vol 64, 1322-1325, Copyright © 1985 by International & American Associations for Dental Research Online Journals
A new technique for screening chemical toxicity to the pulp from dental restorative materials and procedures
W. R. Hume
An in vitro test system is described which allows for quick and relatively
inexpensive examination of the potential for chemical toxicity to the pulp
of materials and procedures used in the restoration of single teeth. The
test system consisted of two sequential steps. First, a restorative
procedure was carried out on a freshly-extracted human tooth crown, to the
pulpal surface of which had been attached a chamber filled with sterile
tissue-culture medium. The preparation was kept at 37 degrees C. The
culture medium was removed at day one and replaced with fresh medium, which
was removed at day 3. In the second step, we used a standard tissue-culture
toxicity assessment technique to examine both culture medium samples for
the presence of chemical toxins. In use, this system gave results which
correlated well with the known clinical potential for pulpal toxicity of
various dental materials and techniques. For example, zinc oxide-eugenol
used as temporary filling or base had no apparent potential for toxicity.
Sealing a cotton pellet containing phenol into a cavity was of high
apparent potential toxicity. Acrylic resin as intracoronal or extracoronal
fillings showed potential for toxicity; this potential was decreased by
lining with calcium hydroxide cement. Composite resin placed onto etched
dentin had apparent toxic potential, but had less such potential when
placed onto unetched dentin. The technique had some advantages over
previously described in vitro toxicity test for restorative materials,
because it included a step requiring diffusion of potential toxins into and
through human dentin, and because it allowed for examination of variations
in technique which mimic clinical behavior, and of materials used in
sequence or in combination.
