Final answer:
The restorative material indicated for use when decay has extended into or close to the pulp is glass ionomer cement.
Step-by-step explanation:
The restorative material indicated for use when decay has extended into or close to the pulp is glass ionomer cement. Glass ionomer cement is a type of dental material that contains fluoride and is used to restore teeth that have decayed near the pulp. It is commonly used in situations where the decay is deep and close to the nerve of the tooth.