These two words have traveled through centuries and multiple languages; both originate from Latin. The (Latin) prefix “re” indicates repetition.
Restoration is from (re)staurare, meaning to repair/give back/build up again. Regeneration is from generare, which means to give birth/generate.
Restorative is commonly used for describing aspects related to individuals; it is employed in social disciplines such as healthcare (e.g., restorative medicine), education (e.g., restorative school practices), and philosophy (e.g., restorative justice) to express forms of reparation of the self/person.
By contrast, regenerative is frequently employed in sciences—such as ecology, biology, and medicine—to indicate a functional self‐renewal or—more often—a morphogenic replacement of lost or damaged parts or structures in organisms or ecosystems.
Regeneration represents a form of upgrade from restoration. If restoration means “to make something well again,” regeneration, for some authors, means “to make it better” than a (supposed) origin condition.