Objectives: The objective of this study was to evaluate and compare the effect of incorporating 5% zirconium powder to conventional acrylic resin and injection molded thermoplastic resin denture bases regarding the fracture resistance.
Materials and Methods: The study was performed on acrylic models of a completely edentulous mandibular arch with two implants installed bilaterally at the canine areas. Fifteen duplicates of the model were done on which fabrication of three types of dentures was carried out. Group 1 conventional acrylic resin heat cured PMMA, group 2 conventional acrylic resin heat cured PMMA + 5% zirconium powder and group 3 thermopress flexible polymeric +5 zirconium powder. Fracture test was done using the universal testing machine. The load required to fracture the denture bases was recorded in Newton. The data was collected and tabulated for statistical analysis.
Results: There was a statistically significant difference between the 3 types of denture bases regarding the fracture resistance in which the highest mean value of 4941.20 was recorded with the conventional acrylic denture base reinforced with 5% zirconium powder followed by bre.flex flexible therompress polyamide reinforced with ZrO2 then the conventional acrylic resin which presented the lowest mean value of 1336.00.
Conclusion: The fracture resistance of the conventional acrylic resin denture base after reinforcement was the highest amongst the tested materials which renders it as a good alternative to conventional acrylic denture base for construction of mandibular implant supported over denture.
Acrylic resins denture base; over denture; denture fracture; mechanical properties; fracture resistance