Which material is recognized as a poor thermal conductor and serves as a good thermal insulator?

The chosen answer identifies zinc phosphate cement as a material recognized for its properties as a poor thermal conductor, making it an excellent thermal insulator. In dentistry, thermal insulation is crucial for protecting the pulp and surrounding tissues from temperature fluctuations caused by restorative materials or environmental factors.

Zinc phosphate cement is formulated to reduce transmission of heat and cold, which is particularly important when it is used as a base or a liner under restorations. This property is beneficial as it helps to preserve pulp vitality and maintain comfort for the patient after the placement of dental restorations.

In contrast, other materials mentioned, such as amalgam and gold alloy, are excellent thermal conductors, which can contribute to sensitivity issues if placed directly against pulp tissue without adequate insulation. Calcium hydroxide is better known for its therapeutic properties and as a pulp protector rather than for thermal insulation qualities. Thus, zinc phosphate cement stands out specifically for its recognized ability to insulate against thermal changes effectively.