Wettability of denture base materials: a comparative invitro study

Background & objectives: In edentulous patient, the replacement of teeth and lost tissues with a complete denture to obtain an acceptable functional and esthetic result remains an important challenge for the practitioner. Retention is that quality inherent in the prosthesis to resist the forces of dislodgement along the path of placement, which is in turn dependent on the “wettability” of denture base materials. There are various types of denture base materials that are used to fabricate the complete denture prostheses. Since wettability influences comfort and retention of complete dentures, a study to comparatively evaluate the wettability property of denture base materials available in our country would be helpful in assessing their role in the success of prosthesis. Method: Mainly five autopolymerising and five heat cure denture base materials are included in this study. The samples (200 in total) were made and the half of them was sand abraded and the remaining half was untreated. The wettability of the samples was checked with Telescopic Goniometer, using artificial saliva as the wetting medium. The wettability of the solid by a liquid is determined by measuring the contact angle () between the drop of the liquid and the plane surface of the solid. A low contact angle indicates good wetting and the high contact angle value indicates poor wetting. The advancing and receding contact angles were recorded and the equilibrium contact angle is measured using the equation. The difference between the advancing and the receding contact angles (Contact angle Hysteresis) were also found which is directly related to the complete denture retention. Results: The statistical analysis was carried out using ANOVA (Analysis of variance - Fishers F test) and Mann- Whitney ‘U’ test (Z) using SPSS version 10. Here mean and standard deviation of contact angle hysteresis and equilibrium contact angle of each group were also taken in to consideration. The present study showed that the surface treatment increases the wettability of the denture base materials. Among the selected five heat-cure and five autopolymerized brands, the DPI heat-cure as well as DPI autopolymerized sand-abraded samples have shown the highest range (11.3 and 10.1 respectively) of contact angle hysteresis compared to their conventional groups and believed to provide more denture retention compared to other brands selected for the study. Conclusion: The increased surface area and the high hydrophilic nature exhibited by the sand-abraded samples is believed to be the main factor which increase its contact angle hysteresis and the increased retention of the complete denture. Among the studied samples from both autopolymerized and heat-cure materials, the DPI sand-abraded samples showed the highest range of contact angle hysteresis.