<prompt> In which of the following materials, moisture loss has to be taken care of?Alginate impressionPolyvinyl siloxaneBothNone  <response>: Alginate impressions can distort quickly if they are allowed to gain or lose moisture, so the impression is wrapped in wet paper towels to serve as a humidor.Preoperative PVS impressions do not need to be wrapped. The preoperative impression is placed aside for later use in forming the temporary restoration.Sturdevant operative dentistry 7th Edition, Page No:120 