Exothermic describes the setting reaction that occurs in what cement when used as a base?

The correct answer is zinc phosphate, which is known for its exothermic setting reaction. When zinc phosphate cement is mixed and set, it generates heat as a result of the chemical reaction between its components, specifically the zinc oxide and phosphoric acid. This exothermic reaction can have significant clinical implications; for example, if the cement is applied too thickly, the heat generated may cause sensitivity or damage to the pulp tissue beneath the restoration.

In contrast, glass ionomer cement does not produce a significant amount of heat during its setting process, as its reaction involves an acid-base reaction that is typically endothermic in nature. Resin cement also undergoes a polymerization reaction that does not generate notable heat. Calcium hydroxide setting does not involve an exothermic reaction either, as it primarily functions through hydration with minimal temperature change.

Understanding the setting reactions of various cements is critical for determining clinical applications, ensuring appropriate selection in relation to the tooth structure and potential sensitivities associated with the exothermic nature of certain materials.