What is the likely pulpal status of a tooth associated with a parulis?

A parulis indicates the presence of a chronic periapical abscess, which arises only when the pulp has become necrotic and infected. The necrotic pulp tissue serves as a substrate for bacterial proliferation, leading to periapical breakdown and pus accumulation. The body creates a sinus tract to drain this pus, which opens as a parulis on the mucosa. A vital pulp cannot produce a parulis — the tooth must have pulp necrosis. Vitality tests on a tooth with a parulis will typically show a non-responsive result.