Abstract:
The purpose of this research was to study the effect of viscosity and holding time on retentive force of denture adhesives. The research was carrying on 17 test groups as follows: no denture adhesive, 12 kinds of custom made adhesive gels and 4 kinds of commercially available denture adhesives. (2 pastes were Polident and BonyPlus, 2 powders were Denstet and Dentfix) In 5 volunteers, the experimental was divided into 2 parts. The first part was to measure viscosity by using Paar Physica MC I Head Z4 at shear rate of 100 rounds per second at temperature of 37degrees celsius. The results showed that the viscosity of the custom made denture adhesive correspond to the concentration. The second part was to measure retentive forces at the holding of time 0, 30, 60 and 120 mins. Each substance was tested repeatly for 3 times and the data were analyzed using One-way ANOVA (p<0.05). The retentive forces of all adhesive gels from the same gel former with different viscosity showed statistic difference except Carbopal groups. The retentive forces from all adhesive gels and Denstet were highest initially and decreased when the time went by. While the retentive forces from the adhesive pastes were low initially and increased when the time went by. For Dentfix case, the retention forces in various holding time were not different. In conclusion, the viscosity and holding time did affect the retention of denture base.