Final answer:
Among amalgam, direct gold, tooth structure, and composite resin, amalgam has the highest linear coefficient of expansion. This greater expansion rate can lead to thermal stress in dental fillings. Additionally, changes to volume, cross-sectional area, and height due to temperature changes in materials are based on thermal expansion principles.
Step-by-step explanation:
Of the materials (amalgam, direct gold, tooth structure, and composite resin), amalgam has the highest linear coefficient of expansion. Compared to other dental materials, amalgam generally has a higher expansion coefficient because it frequently contains metals like silver and mercury. Thermal stress, or the stress resulting from temperature variations that can cause materials to expand or contract, can be exacerbated by this high expansion. For instance, dental fillings composed of materials that expand or contract at different rates than tooth enamel may become uncomfortable or break when exposed to extremely high or low temperatures.
We use the thermal expansion formula to compare the changes in volume, cross-sectional area, and height of two blocks (Block A and Block B) of varying sizes experiencing a temperature change. The coefficient of volume expansion (β) of the material multiplied by the temperature change (ΔT) and the initial volume (V) determines the change in volume (ΔV). Given that the material used to make both blocks is the same and that they experience the same temperature change, the volume changes in each block will be exactly proportionate to their initial volumes.