摘要：

Tissue conditioners are soft polymer gels which are widely used in
Prosthodontics. The powder used is normally poly(ethy1 methacrylate) PEMA or its
copolymers and the liquid is a mixture of ethanol and plasticizer. The gelation
process is purely based on a physical process and is due to polymer chain
entanglement. Phthalates are the most commonly used plasticizer in tissue
conditioners, and their leachability has been a concern over the years. The main
problem with phthalate plasticizers is biocompatibility, as they have been proven to
possess estrogenic activity and cytotoxicity. Therefore a new formulation using
acetyl tributyl citrate (ATBC) has been formulated for this study in an attempt to
replace the phthalate plasticizer. The aim of this study was to compare the effect of
food simulating solutions on the change in hardness of two experimental tissue
conditioners containing different plasticizers. The Shore A hardness values of two
experimental tissue conditioners, PEMA with 95% BPBG and 5% ethanol, and
PEMA with 95% ATBC and 5% ethanol, were compared when immersed in
different types of food simulating solutions such as distilled water, artificial saliva,
25% ethanollwater mix, 3% citric acid and also coconut oil at 37OC, for 84 days. The
results of this study have shown that; both materials exhibited an increase in
hardness value over time, but the tissue conditioner with ATBC plasticizer had a
significantly higher hardness value after immersion in all solutions, except in
coconut oil. The highest percentage of change in hardness was noted in coconut oil
for both materials. Further research needs to be done to improve this formulation, in
order to obtain a clinically acceptable tissue conditioner.

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