Effect of Anatase Titanium Dioxide Nanoparticles on the Flexural Strength of Heat Cured Poly Methyl Methacrylate Resins: An In-Vitro Study.

Poly methyl methacrylate (PMMA) resin is the most widely used material for fabrication of dentures since 1937 as it exhibits adequate physical, mechanical and esthetic properties. But one of the major problems faced using this material is that, it is highly prone to plaque accumulation due to surface porosities and its food retentive properties. This in turn increases the bacterial activity causing denture stomatitis. In efforts to impart antimicrobial property to these resins, various nanoparticles (NP) have been incorporated viz. Silver, Zirconia oxide, Titanium dioxide (TiO2), Silica dioxide (SiO2) etc. However, as additives they can affect the mechanical properties of the final product. Therefore, the aim of the present study was to evaluate and compare the effect of different concentration of TiO2 NP on the flexural strength of PMMA resins. Specimens made from heat polymerizing resin (DPI) without NP were used as a control group (Group A). The two experimental groups, (Group B and Group C) had 0.5 and 1 % concentration of TiO2 NP respectively. The specimens were stored in 37 °C distilled water for 50 ± 2 h. A three-point bending test for flexural strength measurement was conducted following ADA specification no. 12. The maximum mean flexural strength (90.65 MPa) belonged to the control group; and acrylic resin with 1 % TiO2 NP demonstrated the minimum mean flexural strength (76.38 MPa). But, the values of all the three groups exceeded the ADA Specification level of 65 MPa. Conclusion may be drawn from the present study that addition of TiO2 NP into acrylic resin can adversely affect the flexural strength of the final product and is directly proportional to the concentration of NP.