Final answer:
Polysulfide rubber (mercaptan) impressions should be poured within 30 minutes to minimize distortion.
Step-by-step explanation:
Polysulfide rubber (mercaptan) impressions should be poured within 30 minutes to minimize distortion. Polysulfide rubber is a type of elastomer used in dentistry to make dental impressions. It has a slow setting time, meaning it takes some time for the impression material to fully cure and harden. If the impression is poured too late, it may have deformations and inaccuracies.