Journal of Dental Research, Vol 66, 1393-1398, Copyright © 1987 by International & American Associations for Dental Research Online Journals
Phenytoin and 5-(p-hydroxyphenyl)-5-phenylhydantoin do not alter the effects of bacterial and amplified plaque extracts on cultures of fibroblasts from normal and overgrown gingivae
Q. T. Smith and J. E. Hinrichs
Local irritation of gingival tissue by plaque is among the factors which
affect development of gingival overgrowth in patients undergoing chronic
phenytoin (PHT) therapy. Variability in the cytotoxicity of plaque
components or of plaque substances plus PHT and/or its metabolites toward
gingival fibroblasts may relate to whether gingival overgrowth forms in a
particular patient. Fibroblasts from healthy and overgrown gingivae were
incubated with (a) PHT and its major human metabolite,
5-(p-hydroxyphenyl)-5-phenylhydantoin (HPPH), (b) microbial and "amplified"
plaque extracts, and (c) microbial and "amplified" plaque extracts plus PHT
and HPPH. Cell numbers and cell-associated protein were determined for each
incubation preparation. A wide range in cytotoxic response to a particular
microbial or plaque extract occurred among cell strains. Plaque extracts
from different subjects had variable cytotoxicity toward a cell strain. The
differences among fibroblast strains in response to an extract and the
variability in cytotoxicity of different plaque extracts toward a cell
strain were not related to their source from normal or overgrown gingivae.
Cell numbers and cell-associated protein were similar for incubation
mixtures containing extracts with and without PHT and HPPH. These data do
not show differences among cytotoxicity levels of plaque extracts, the
response of particular gingival fibroblast strains to plaque components, or
interaction between drugs and certain plaque samples which explain
development of gingival overgrowth in some subjects receiving chronic PHT
therapy.
