Evaluation of the effect of adding zirconium or titanium oxide powder to heat cured acrylic resin on the fracture resistance of denture base of the mandibular implant supported overdenture. An invitro study

Objectives: The objective of this study was to compare the fracture resistance of denture base of an implant supported mandibular overdenture when incorporating either 5% zirconium or titanium oxide powder to conventional heat cured acrylic resin. Materials and Methods: A completely edentulous epoxy mandibular model was used in this study with two root form implants installed bilaterally at the canine areas. The model was duplicated 15 times into dental stone according to the sample size calculation. The 15 models were divided into three groups, five model in each. In the first group an implant retained overdenture was constructed with conventional heat cured acrylic resin denture base. In group two the overdenture was constructed after adding 5 % zirconium powder to the conventional denture base material, while the denture base of the third group contained 5% titanium oxide powder added to the conventional denture base material. The universal testing machine was used to evaluate the fracture resistance of the three types of overdenture. The recorded data was collected, tabulated and statistically analyzed. Results: The results of this study revealed that there was a statistically significant difference between the 3 types of denture bases regarding the fracture resistance where the highest mean value was recorded for the conventional acrylic denture base reinforced with 5% zirconium powder followed by that containing the titanium oxide powder while the conventional denture base showed the least values of fracture resistance Conclusion: Reinforcement of the conventional heat cured acrylic resin denture base material increased the fracture resistance of the denture base when used in mandibular overdenture cases retained with two implants.