RESUMO
Background: Provisional Prosthesis in fixed partial dentures are subjected to Flexure under stress. Selection of appropriate material for fabrication of Provisional is of utmost importance as the Provisional prosthesis has to remain in function till definitive prosthesis is delivered. Material & Methods: Bar type specimens of four different commercially available brands for provisional restorations fabricated according to ADA specification No. 27 and immersed in artificial saliva. The specimens were fractured under 3-point loading test. Results: The flexural strength ranged between 60 to 110 Mpa. BisGMA Auto polymerizing composite resin from Dentsply Caulk shows the highest flexural strength. Conclusion: Within the limitations of this study, the flexural strengths were material specific rather than category one. The BisGMA composite based resin shows significantly higher flexural strength over other materials
RESUMO
Background: The color stability of commercially available denture base acrylic resins (Lucitone-199, DPI and Travelon-HI) was studied in vitro. Material & Methods: The specimens were exposed to tea, coffee and turmeric solutions at 37 ± 1 °C. Colour measurement of the specimens from each brand of denture base acrylic resin recorded by spectrophotometer. The specimens were washed under distilled water and dried before measuring the colour on 0, 10, 20 and 30 days of immersion and color differences were calculated. Results: Statistically the colour change was significant between and within the groups of different heat cure denture base acrylic resins. Conclusion: Where as Lucitone-199 heat cure showed the highest colour variation in tea and coffee followed by DPI and Travelon-HI.
RESUMO
Background: Two potential problems commonly identified with a denture base incorporating a resilient liner are afailure of the bond between the acrylic resin and resilient liner material and a loss of resiliency of the resilient liner material over time. Methods: The current study was performed to assess the bond strength and hardness of acrylic resilient liner in both auto-polymerized and heat-polymerized forms and silicone resilient liner in auto-polymerized form to a processed denture base resin over a period of water storage for 1 day, 1 week and 1 month. The denture liners investigated were acrylic resin-based heat-polymerized (Super-soft), acrylic resin-based autopolymerized (Coe-Soft) and silicone based autopolymerized (GC-reline) resilient liner. The resilient liners were processed according to manufacturer’s instructions. Tensile bond strength was measured in ASI Instron universal testing machine at a crosshead speed of 20 mm/min, and hardness was measured using a Shore-A durometer. Results: Two-way ANOVA and Tukey HSD tests were used to analyze the data (α=0.05). The results indicated that there were significant differences both in the hardness and bond strength values of resilient liner materials. Conclusion: Autopolymerized silicone resilient liner has increased bond strength and hardness values than autopolymerized acrylic liner but the bond strength and hardness values of autopolymerized silicone liner was less than heat cure acrylic resilient liner.