Thermal Conductivity and Diffusivity of Human Enamel and Dentin Measured by the Laser Flash Method

Abstract

Precise information regarding the thermal properties of human tooth structure such as its thermal conductivity and diffusivity can increase the accuracy of heat transfer modeling, which has recently gained popularity. Moreover, such information is highly important for designing and production of dental materials. Since thermal conductivity and diffusivity of human enamel and dentin can be temperature dependent, the laser flash method was used in the present study to measure the diffusivity of human enamel, sound dentin, and carious dentin. Also, data obtained by differential scanning calorimetry (DSC) were used to measure the specific heat and then thermal conductivity was calculated. The results revealed that by an increase in temperature, the conductivity of enamel, sound, and carious dentin increased. The conductivity of enamel at 30 °C, 40 °C, and 50 °C was 0.81 W·m⁻¹·K⁻¹, 1.20 W·m⁻¹·K⁻¹, and 1.53 W·m⁻¹·K⁻¹, respectively. These values were 0.44 W·m⁻¹·K⁻¹, 0.91 W·m⁻¹·K⁻¹, and 1.15 W·m⁻¹·K⁻¹ for sound dentin and 0.78 W·m⁻¹·K⁻¹, 1.01 W·m⁻¹·K⁻¹, and 1.33 W·m⁻¹·K⁻¹ for carious dentin, respectively.