Statement of Problem: Proper bond of the soft liner to acrylic denture base is one of the most important factors in the longevity of soft liner. Since the antifungal efficacy of clotrimazole in soft liners has been approved, it is necessary to determine its effect on the physical properties of soft liners.
Purpose: Determination of the tensile bond strength of the silicone soft liner (GC-Extrasoft) containing clotrimazole to the acrylic denture base, when the specimens are stored in distilled water and washed daily with wet cotton, was the goal of this in vitro study.
Materials and Method: Forty two pairs of acrylic base (3cm length and surface area of 10 mm2) were prepared. The specimens were divided into 2 equal groups of control and case, each consisting of 21 specimens. Silicone soft liner was added between them with a thickness of 3 mm after treating the acrylic surface with isopropyl alcohol and application of adhesive layer. Clotrimazole 1% by weight was incorporated into soft liner in the case group. The control group consisted of S1, S30, S60 and the case group of Sc1, Sc30, Sc60 that were stored in distilled water and washed with wet cotton for 1, 30 and 60 days, respectively. Tensile bond strength was measured by universal testing machine at a cross head speed of 10 mm/min. Seven specimens of the groups were evaluated each time. Finally, the results were analyzed, using Two-Way ANOVA.
Results: The means and standard deviations of tensile bond strengths in the control group after 1, 30 and 60 days were 0.52 ±0.19, 0.58±0.28, 0.60±0.25 and were 0.60±0.32, 0.50±0.18 and 0.55±0.42 in case group, respectively. There was no statistically significant difference in tensile bond strength between control and case groups ( p >0.05).
Conclusion: No significant effect on tensile bond strength of the soft liner into the acrylic denture base was seen by adding clotrimazole to the silicone soft liner (Gc-Extra soft) after 1, 30 and 60 days of storage in distilled water and cleaning with wet cotton.