Effect of titanium dioxide and zirconium dioxide nanoparticle incorporation on the thermal conductivity of heat-activated polymethylmethacrylate denture base resins: An in vitro experimental study.

Aim: The aim is to determine thermal conduction by heat-activated polymethylmethacrylate (PMMA) infiltrated with 1 weight% Titanium Dioxide (TiO2) and 1 weight% Zirconium Dioxide (ZrO2) nanoparticles and to compare with that of conventional PMMA.

Study setting and design: In vitro experimental study.

Materials and methods: Eighteen disc shaped specimens with a thickness of 5 mm and diameter of 50 mm, were fabricated and grouped according to the material used: Group B1 (resin infiltrated with 1 weight% TiO2), Group B2 (resin infiltrated with 1 weight% ZrO2), and Control Group B3 (heat-activated conventional PMMA resin). Disc-shaped specimens were analyzed for thermal conductivity using "modified guarded hot plate apparatus" in the thermal lab of the Indian Space Research Organisation.

Statistical analysis used: One-way ANOVA followed by Tukey's post hoc test was used to compare the arithmetic means of all three groups.

Results: A statistically significant difference was noted among all three groups. Group B2 had the maximum thermal conductivity, followed by Group B1. Thermal conductivity was the least for Group B3. A post hoc comparison revealed that the difference was significant between Group B2 and Group B3.

Conclusion: Nano ZrO2 addition in PMMA increased its thermal conductivity. There is evidence that it improves its mechanical properties as well. Hence, Nano ZrO2 addition in PMMA is highly recommended. Nano TiO2 addition in PMMA did not provide any significant advantage in terms of thermal conductivity, but its addition in PMMA is justified because of its mechanical and antimicrobial properties.