Nano-fluorohydroxyapatite (nano-FHA) is a caries preventive agent that is applied in many fields of dentistry and has the potential of being added to Essix retainers to create antibacterial properties. Objectives The purpose of this study was to investigate the effect of nano-fluorohydroxyapatite addition on the tensile strength and modulus of elasticity of an Essix plate. Methods The nano-fluorohydroxyapatite was synthesized and added to an Essix plate in various weight percentages: 0% (group 1), 0.1% (group 2) and 0.5% (group 3). We performed the measuring of flexural strength and modulus of elasticity for the experimented three groups using a universal testing machine. The data were analyzed through one-way ANOVA and Tukey’s test at the significance level of 0.05.
Accordingly, the obtained results were indicative of significant differences between the groups (P-value = 0.003); however, the difference between group 2 and control group was not statistically notable (P-value = 0.427). Furthermore, the tensile strength of group 3 significantly decreased (P-value = 0.04). In regards to the modulus of elasticity, the data were suggestive of significant differences between the groups (P-value = 0.002). Apparently, the modulus of elasticity of group 2 and group 3 decreased significantly compared to that of the control group (group 1). Conclusions We can conclude that nano-FHA can be incorporated into Essix plates in concentrations of up to 0.1 wt% in order to create some caries preventing effects with no negative effects on tensile strength; however, adding nano-FHA to Essix plate will decrease modulus of elasticity.