Abstract
The advantages thermoplastic denture adhesive are that it does not dissolve in the oral cavity and is reusable by washing for a few days. However, it has some disadvantages such as squeezing out of the tube and peeling off frorn the resin denture base.
To improve this adhesive's of ease use, several types of additives were evaluated.
As a result, polypropylene glycol (PPG) was selected.
The effect of PPG was evaluated by laboratory tests (squeeze test, peel off test) devised by our laboratories.
The mechanisrn of PPG effects was established by deterrnining physical properties such as the tensile strength and critical surface tension of used denture adhesive.
As the amount of PPG in denture adhesive increased, squeezability and removability were improved. The highest effect was observed at 5% of PPG.
The results of clinical tests and these laboratory tests showed a good correlation.
It is suggested that the laboratory tests can be used to predict irnprovernent for ease of use for the future development of denture adhesive.
Improvement of squeezability is due to less adhesion to the inner surface of the tube. Improvement of rernovability is due to both less adhesion to the resin denture base andinCreaSe Of elaStiCity.
These results were supported by laboratory tests which demonstrated the decrease of critical surface tension and the increase of thetensile strength of denture adhesive.
